Conference vmszoo::rc

>    CURRENTLY THERE ARE MANY TYPES OF GLUES ON THE MARKET. IN EACH OF
>    THE CATOGORIES (CA, EPOXY, WHITE ALAPHATIC) DOES ANYONE HAVE ANY
>    PREFERENCE??
    
>    BOB G.

* Bob,

Actually, I prefer them "all," for specific applications, of course.  To your
list, I'd also add cellulose glue, what used to be referred to as plain old 
airplane glue like Ambroid, Testors Formulas A & B, etc.  While this type cement
is becoming rarer all the time, it still has its applications.

During construction of a model, I'll likely use a little of all the glue types
thus far mentioned.  I like the aliphatics [PICA, Titebond, etc.] for butt-join-
ing balsa and ply parts, applying sheeting, etc. Firewalls and other high-stress
areas call for epoxies [I normally prefer the 30-minute variety]. I use the CA's
mostly in interior areas where I can take advantage of this glues ability to 
flow readily and wick into tight/confined areas.  Finally, I prefer cellulose 
glues for butt-joining exterior, low-stress area sheeting for it's superb sand-
ability.

I know that the CA mfgr.'s are quick to suggest that an entire airframe can be 
built using various CA types and they're probably correct but I'm still old-
fashioned enough not to trust it in certain areas and I hate trying to feather-
sand surface areas where CA joints appear.  I prefer to use a variety of adhe-
sives, taking advantage of each's good points while avoiding the bad ones.

Adios,	Al

    It's really great to have the variety of adhesive resources at our
    disposal.  I strongly concur with Al that each type has it's specific
    applications and that everyone should learn where each type is best
    used.  I also use silicon adhesive for sealing fuel tubing exits
    and around the engine compartment.  The permanent flexability and
    excellent resistance to fuel makes silicon very useful.  You need
    a clean surface and it takes a while to dry, but it will not crack
    due to vibration and it acts as a shock mount.  If you bring brass
    tubing through the firewall, the silicon will prevent it from
    fracturing due to vibration.  I had this unpleasent experience using
    epoxy to seal the tubing exit in the firewall.  
    	Contact adhesives are also very useful for sheeting foam wings.
    Double sided tape can also be used for this.  
    	RC56 is another great adhesive where permanent flexability is
    desired.  I use it to bond canopes to the fuse.  The stuff doesn't
    tend to run and it dries clear and flexable.
    
    Charlie
    

    
    The adhesives I use and their application;
    
    
    	CA, Thick                       All wood to wood joints
    	5 min. epoxy                    With fiberglass cloth for
    					filleted joints
    	30 Min. Epoxy                   Sheeting wings
    	Titebond (white glue)           Butt jointing wing sheeting
    	RC56                            Canopy installations
    	Silicon                         Sealer, Glueing servo trays
    					into fiberglass fuse's
    	Double stick tape               Securing switched,charging jacks
    
    
    
    						Tom

    re: .3
    
    Double sided tape for sheeting foam wings...sounds too good to be
    true. What about strength??
    
    Cheers,
    
    Keith.

    I just read an article - i have a xerox at home of it - in some
    material handling mag about double sided tape made by 3M. Its foam
    based. One use described as in some road marker (a box with some
    lettering) that used to have the joint riveteed. The rivets where
    replaced with this tape. simpler to make and all that stuff.
    
    The kicker is that a car ran into the marker. The steel was ruptured
    at the corner. The joint held !!! Sounds liek winner to me.
    Now my question was how will the adhesive behave when used with
    two differrent materials. And also how rigid is bond. Epoxy gives
    a very stiff wing comparesd to other stuff like contact cement or
    titebond..
    
    md
    

    I glued a piece of birch plywood to the wrong place on a balsa sheet
    and decided to remove it.  The glue was a brand x, super thin CYA; the
    remover PACER debonder.  When I re-glue the piece in nearly the same
    place, what is the prognosis of the new bond?  I expect to sand off the
    surface glue, but the stuff would have soaked in during the initial
    application and perhaps again during the debonding. 

    Re: .-1, Al,
    
    There should be no incompatibility problems whatever.  All the various
    CA products from the many mfgr.'s seem to be completely compatible
    with each other.  Would that this precedent carried over into other
    model products, e.g servo connectors, engine bolt-hole patterns/crank-
    shaft lengths, etc., etc., ad infinitum.
    
    Adios,	Al

    re   debonded CYA rebonding
    
    The concern is not so much the compatibility of one manufacturer's
    CYA with that of another as it is the affect, if any, of the debonder
    upon the subsequent glue joint.  Here are some of the possibilities:
    
    	Does the debonder chemically change the material in the joint
    	and thereby create compounds that will affect the future joint?
    
    	Does the residue of CYA in the pores of the wood block the next
    	infusion of CYA and give a weaker joint thereby?
    
    	Is there a residue of the debonder that will contaminate the
    	future joint?
    
    I guess what I really want is:
    
    	First,      what experience is out there in this situation?
    
    	Distant second,      if a bummer, then why?
    
    Because for the most critical, but misplaced joint, I have not yet
    debonded it; I can instead machine the area to a correct configuration.
    The easier path is to debond and reglue.

    AL,
    
    Depending upon the surface area of the CA'd joint, you may, indeed,
    have to consider reshaping/refabricating the part as the debonder
    is not likely to penetrate too far into the joint, particularly
    where hardwood(s) are involved.
    
    Debonder is a solvent which temporarily softens the hardened CA but,
    once it's evaporated [and it happens pretty fast], no residual remains
    to undermine a subsequent joint.  Matter of fact, once the joint
    is softened, you gotta' work quickly to separate the involved pieces
    before the CA hardens once again.  You may use debonder with no
    fear whatsoever of there being any undesireablr side effect(s). 
    
    Adios,	Al

On the subject of glues, the January 1988 issue of Consumer
Reports has an article on glues.  While none of the glues tested
were specifically model glues, they did test various brands of
epoxy and CYAs and tabulated their characteristics.  I put out a
request for the issue amongst my department and got several
offers of copies, so I'm sure it won't be hard to get one for
yourself. 

I don't know what "de-bonder" is, but I recall reading that CA mistakes can
be corrected with acetone.  Pure acetone evaporates very quickly, and with
no residue.  Before joining DEC, I was a marine biochemist, and we used
acetone as a final rinse for very-clean glassware.  The acetone rinses away
water, then evaporates in seconds.

If "de-bonder" is acetone, I doubt it would create problems with subsequent
joints.

Just remember not to breathe the stuff, and avoid getting it on your skin.  In
addition to drying your skin to the point of brittleness, exposure to acetone
(fumes or liquid) is implicated in various liver disorders.

Dave

    The debonder that I have says that it is Nitromethane on the bottle.
    It is sort of yellow in color.  It evaporates rapidly and I doubt
    that it would contaminate the joint.  Acetone also is a good solvent
    for CYA.
    
    Charlie
    

>< Note 409.12 by AKOV02::DHUGHES "the OTHER Dave Hughes..." >
...
>I don't know what "de-bonder" is, but I recall reading that CA mistakes can

Well Dave you should.  Everybody should for safety sake.  If you don't have
de-bonder - get some and keep it on your work bench close to the CA.
I wouldn't put the stuff in my eye - I would go to the Doctor for that - but
I would bring my de-bonder along with me.  I have had my fingers glued to so
many pieces that it was physically difficult to open the lid on the de-bonder
and set myself free.  I don't want to start a big discussion here but De-bonder
is cheap and lasts nearly forever.  I'm on my second bottle after 11 airplanes.
Actually I would still be on my first bottle but Al Casey suggested I seal
the seam of my MonoKote with CA.  After I used up half a bottle cleaning up
the mess I made.  If you ever get a little CA on MonoKote - just apply
a little De-bonder and rub with a Kleenex.  It may take 4-5 tries but the
MonoKote will look good as new when you are done.

              _!_      
Bye        ----O----   
Kay R. Fisher / \     

================================================================================

    While acetone _is_ an excellent CA debonder, it's not very practical
    in many/most applications as it attacks nearly any kind of plastic
    and/or paint.  Short of cleaning up CA spills on glass, formica,
    etc., I'd advise considerable caution before using it on yer' pride
    and joy.  ALWAYS test in a place that doesn't show or matter BEFORE
    applying acetone to a models finished surface.
    
    Debonder, while still a solvent [someone suggested nitromethane],
    is a little kinder to finished surfaces and plastics but beware,
    it can also attack many finishes/paints.  Again, test it before
    committing yer'self...you'll save yer'self a lotta' grief by doing
    so.  While testing in some innocuous area, apply the debonder
    liberally several times, rubbing vigorously...the stuff's sneaky
    and frequently seems to be doing it's thing while leaving the surface
    unaffected; having lulled you into a false sense of security, it'll
    suddenly attack the surface leaving you gritting yer' teeth and
    turning the workshop air blue.  This tells you that you _may_ get
    away with using it if you don't overdo it.
    
    Epoxy finishes like K&B seem invulnerable to both debonder and acetone
    but, aside from these, I suggest caution using debonder on almost
    any finished surface...ALWAYS TEST FIRST!
                                      
    Adios,	Al

    It is very true that acetone will dissolve most plastics and it
    is even used to weld plastics.  It is also true that CA will also
    attack most plastics before it has set.  I have had this problem
    with slow zap a couple of times.  It goes through foam like butter
    as well.
    
    Charlie
    

        CA debonders are toxic to the skin, so don't use them to unstick
        yourself. I routinely apply CA with my fingers; it is a trick that
        needs to be learned. Large puddles won't cure, so you can spread
        them around. Most important is knowing when to get your finger OFF
        whatever it is on. That hot kick tells you to let go QUICK! This
        isn't for evderybody, and don't blame me if you end up stuck to
        your model, but it does work for me. 
        
        A couple other useful glues:
        
        HotMelt: For tacking things in place. Also good for water/air
        tight seals.
        
        Amberoid or Duco: I use this on HLGs and other places where
        weight is critical. It is also easy to disolve, so if you need
        to make a minor stab adjustment, you can take the stab off,
        and re-stick it on. A little dope thinner does it.
        
        24 hour epoxy: Where strength is important. I have little use for
        any other type of epoxy. The 5-minute crap never gets hard, but
        does get brittle with age. It can be peeled right off. Most of it
        isn't hot fuel proof either! 
        
        Safe-T-Poxy: A laminating resin used in place of the polyester
        stuff. It takes longer to dry, but I find it easier to work with.
        No skin toxicity problems or nasty fumes either. 

        Masking Tape :-)

>< Note 409.17 by CHGV04::KAPLOW "sixteen bit paleontologist" >
>                          -< careful with debonders >-
>
>        CA debonders are toxic to the skin, so don't use them to unstick
>        yourself. I routinely apply CA with my fingers; it is a trick that

I checked my bottle again last night and it states right on the bottle that
you can use debonder for removing CA from skin.  Therefore I don't believe
that debonder is toxic.  If so maybe only some debonders?  Anyway the debonder
that says this is made by Pacer Inc. and is called Z7 Debonder.  Now I could 
believe that CA itself is toxic to skin.  Anybody else have any input?
I use debonder on my fingers all the time - maybe that explains some of my
strange behavior?

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================

    those fiendish plastic fingernails that are fashionable
    with the fairer set now, are applied w/ a type of CA. As 
    a result the nail remover that they sell for them does a 
    pretty fair job as a debonder for hobby use. I don't think it
    works as fast as the pacer debonder, but I don't think the
    CA they use for fingernails is as strong as Hot Stuff, Zap,
    and Goldberg CA's, hence the debonder doesn't probably isn't
    as strong. But considering the intended usage, it should/might
    be safe ( and the fact that most drug stores sell it means that
    it's readily available).

    DT

    Z7 debonder is not harmful, I think that you will find that it is
    even water based.  I too sometimes spread CYA with my fingers, but
    I try to put a plastic bag or some wax paper over my finger first.
    Every once in a while I get into an "emergency" situation and have
    to go fingers-direct to the glue.  The secret is to move QUICK or
    your dead.  In the (unfortunately, not so) few times I actually
    glue myself to my model, or the table top, or the doorknob, or myself,
    Z7 has saved me a lot of pain and discomfort.  I have never experienced
    any post-traumatic experiences of the negative kind, other than
    the pain associated with the derision I receive from my wife, for
    the stupidity of glueing myself to inanimate objects.

    Save those little Dubro bags, you know, the one's that hardware
    come's in. They are great as a barrier between flesh and CA. And
    they don't stick to CA.
    
    						Tom

    The debonder I use is nitromethane.  This is toxic stuff.
    
    Charlie
    

    I know acetone will (slowly) debond CYA, and since nail polish remover
    is (mostly?) acetone, and that's not particularly bad for you...
    
    Willie

    Acetone is probably not too bad, but be careful with it - it is
    EXTREMELY flamable.
    
    Charlie
    

Nitro can also be used as a debonder for CA's. It's not as good as the 
commercial stuff but it does work.

One other Safety point with all solvents is that it does remove the natural oil 
from your hands which I am told is dangerous to your health. I cant remember 
why, it's some time ago I was told that by a doctor friend.

John.

    Commercial debonders are Nitro.(At least the stuff I have).  If
    you take the oil out of your skin, it is easy for stuff to get in.
    I always use lots of hand lotion to replace oils after using solvents.
    Some solvents go through skin like it isn't there.
    
    Charlie
    

The night before last my son, who's building a PT-40, assembled the dihedral 
joint of the wing with the plywood wing joiners and 15 minute epoxy. After a
few hours, the excess epoxy in the mixing cup still seemed rubbery and sticky 
rather than hard and glassy. I checked the contents of the two bottles, which 
were still nearly full, and noticed that the contents were not at the same 
level, leading me to believe that the mix had not been 1-to-1. Even after two 
days, some of the material on the joint seems tacky and not glass hard. What 
should we do? Will the stuff finally set up strong given enough time or should
we try to take the joints apart, clean them up and re-epoxy them? The 
instructions said to use epoxy but I'm wondering if gap-filling CA wouldn't have
done just as well. Any opinions?

Dave

    I'd take the joint apart. You should be able to accomplish this
    by taking the wing outside and using a heat gun warm the joint.
    Epoxy warmed usually becomes rubbery. At this point you can pry
    the joint apart. I'd then make new braces and install the new braces
    on the wing joint. I'd stay with epoxy at this point. 
    
    
    						Tom

    
    	Something that may be less painful...  Why not glass the center
    section of the wing, on both sides?  After doing this, the state
    of your internal bracing shouldn't matter as long as all the
    spar/webbing/sheeting joints are in good shape.

    	Comments?

    It pays to do it right the first time.  Whats the point of
    building a plane like the PT40, which is specifically designed to
    take a *LOT* of abuse, incorrectly, just to have it fold a wing at
    the bottom of a loop.  Take it apart, remix some new epoxy (get
    the proprtions right this time) and put it back together.  After
    the epoxy sets, and you are sure that it will harden, then if you
    want some added strength, glass the center.  I can tell you from
    personal experience that there is no worse a feeling than watching
    a plane you just built come apart because you took a "short cut"
    in the construction process.  Be sure to use the heat gun outside
    (or in a really well ventilated area) when you separate the wing
    halves. 

        Which part did you use too much of? Are you sure it was this time,
        and not some earlier batch that wasn't equal. How much of a
        difference was there? Something like 10-20% probably won't make
        much of a difference with hobby grade adhesives. Extra hardener
        tends to set faster, but never gets as hard as it should, while
        not enough hardener sets slower, but gets harder. 
        
        I've also noted that 'fast' (5-15 minute) epoxies never really set
        very hard, and sometimes don't set in the pot either. Check and
        see if what's on the plane set differently than the glob left in
        the pot; what you have may be OK. I'd use a much slower epoxy for
        any job that really needs epoxy strength (12-24 hours). You
        shouldn't be in any rush when building. Save the other stuff for
        field repairs. 
        
        Finally, rubbery epoxy can usually be peeled off with finger
        nails, a knife blade, or other scraper. re-sand the area to be
        glued, just to make sure you get a better bond next time. 

    I tend to agree with .-1. It has been my experience that the 5min and
    15min Epoxies never seem to cure up really hard. I always seem to be
    able to press a finger nail into them, and they usually seem somewhat
    flexible. There is nothing wrong with this, and as long as the stuff is
    not sticky to the touch it is probably OK. Before I went ripping
    anything a part I would mix up a small batch on some scrap pieces and
    see how it dries, then compare that to what you got the first time. If
    the new batch seems significantly better, then I'd take it apart and
    redo it. 
    
    Wayne
                       

    To fix the stab on your Baron................
    
    I hate to give you Whoppie Chop guys this crafty idea seeing how
    it came out of a Pikes Peak SOARING Society Club meeting last night.
    But if you wont be affended niether will I.
    
    Last night a fellow club member (Rex Farris) present an idea of
    a new construction adhesive.  It is called "THE HOUSEHOLD WELDER"
    and should be available at your local Hardware store or convience
    store (Target,K-Mart,Fred Meyer type) it is also similiar to "SHOE
    GOO".  It seems to be ambroid based.  Anyway Rex applied some of
    this to BALSA, Plexiglass, and the Impossible to glue (ABS plastic)
    boy does this stuff stick.  It is not as hard as epoxy but better
    than silicon.  He didnt even clean or ruff-up the ABS and it really
    stuck.  This would be real usefull in mounting stuff on the insides
    of Glass glider fuselodges.
    
    Anyway give it a try.
    

  I have a quick question:  My Carl Goldberg Cub recommends using Super Jet
because of the plywood construction.  Is Zap-a-Gap equivalent to Super Jet?
They both claim to be thicker, good for broad areas and great for laminations.
I realize the the Jet glues are Goldberg products, so of course they are 
going to push them, I just don't want to spend more money than I have to.


   Thanks,  Jim  the-original-Cavanagh-who-doesn't-use-a-U-in-his-name

    Jim,
    
    Rest assured that _any_ of the gap-filling/super CYA's will do the
    job as well as Super-Jet.  As you say, the Jet line of CYA's are
    a Goldberg product and that's why they're specified...the same as
    if Sig kits specified the use of Sig-ment glue or their new CYA's,
    Sig Koverall and Sig dope.  Any brand'll work, they're just promoting
    their own product.    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

 
  Thanks Al,  that's what I figured.  I also know it is better to be safe 
and ask a question than to watch you plane disintegrate in flight due to 
bad glue!


  Jim   

Maybe this has been asked in the glue note before but here goes.

Was looking at an issue of Model Aviation and they were talking about
putting Mica film on...

"Many modelers have objected to the fact that the recommended adhesive
(Balsarite) becomes fluid at about the same temperature as that required
to shrink the film.  Here's my solution:

After coating the frame with Balsarite as recommended by the manufacture, 
add a small bead of Pica Gluit (aliphatic glue which can be sanded) to the 
periphery of the area to be covered, and allow it to dry thoroughly - 30
minutes or more, and up to a month or so if you wish!  This product makes
a great temperature-sensitive adhesive."

Sooooooooo

My question is:
	Is Pica Gluit just a generic aliphatic glue like "Tite Bond"?
    If not can someone describe it in more detail?  

Bye          --+--
Kay R. Fisher  |
---------------O---------------
================================================================================

That's a good one because I've found that its hard to get
balsarite edges to seal.  But it sounds like you're using too
much heat -- when you use balsarite with micafilm you should have
a monokote iron set at about 1 - 1.25; that's all it needs.  The
micafilm shrinkage is minimal, and you can really tighten it up
by putting the iron up a little higher, from 1.5 to 2.
Overheated micafilm takes on a shiny, almost glazed appearance.
You'll get this if you go much over 2.

As to the aliphatic resin, I think they're all the same.  There
was an article recently about using the aliphatic as a heat
sensitive adhesive, much as you use balsarite.  Gonna try that
for sealing the edges, its cheaper than CYA!

    "For What It's Worth" in the April '89 issue of RCM has a note on
    applying baking soda with an artist's brush [for use with CA glue].
    HUH?  Baking soda?
    
    Why?  I never heard of baking soda and cyanoacrylate together. 
    
    Before writing this I tried some experiments, and it seems to benefit
    the setting of the glue.  I tried using just the thin cyanoacrylate
    (CG's Jet) to glue two light bulbs together, and it didn't set; when I
    sprinkled some sodium bicarbonate on the wet joint, the glass bulbs
    were bonded.  (No, I didn't have an application; I just happened to
    have two burnt out bulbs sitting in the top of the trash.)  Trials 
    with wood were less conclusive, but my own experience is limited.
    
    Will some savvy people tell me what is going on here?

    I've used baking soda as both a "kicker" and as a bulk filler with
    CA for a long time.  Satellite City ("Hot Stuff") used to include
    a little folder that mentioned using a small amount of baking soda
    as a gusset maker for difficult-access joints.  The baking
    soda/hotstuff gusset is rock-hard once set.
    
    Watch out if you use it- the baking soda makes the glue "kick" within
    about a second.  Using a whole drop of CA will cause a nice puff
    of smoke to come out of the joint.  It's quite possible to burn
    yourself on the joint.
    
    As always, use good ventilation with CA.
    
    	-Bill  

    CA and baking Soda???  You mean you have never heard of Modelers
    Concrete!!!!!!   This trick works best with the Thin CA, the thicker
    wont penetrate the soda.
    
    It is also handy to get some type of dispenser for the soda so you
    can just put a puff on or lay out a bead for a gussett.
    

    Baking soda kicks CYA because it is a base.  It also acts as a filler
    at the same time.  If you create an acid environment, the stuff
    will not cure.
    

    And if you are sick of paying lots of money for comercial kicker,
    just mix baking soda and water in a spray bottle.  People say it
    works great.
    

    More News!
    
    The February issur of Popular Science contains an article on
    CyA glues that explains away a lot of the mystery.
    
    Let me recap some of the points.  CyA is an organic monomer that
    polymerizes when pressed into a thin film.  This reaction takes
    advantage of the microscopic layer of water that is present on almost
    every surface. This layer is slightly basic and acts as a catalyst.
    
    Now, if you look at the contents of a bottle of Zip-Kicker for example,
    it is made up of freon and aromatic amines - amines are weak bases. 
    The kicker ups the pH of the surface so that when you apply CyA - Wham!
    
    A couple of thoughts.  When you open a bottle of CyA it begins the slow
    process of curing, so that in about six months the stuff is no good.  I
    now buy the smallest bottles which in the long run are more economical
    since I use them before they go bad.  Keep the unused stuff in the
    freezer and it will last up to two years.
    
    After reading the article, I'm more prone to use a kicker and have
    better results than before.  Remember that even though the kicker sems
    to evaporate very quickly (really its mostly the vehicle evaporating)
    the surface remains treated for at least a minute - so don't feel that
    you have to hurry!
    
    If anyone wants a copy of the article send me mail at PEE47::COX, and
    depending on the number of responses I'll mail them out or key it into
    the note.
    
                --|--             Happy (con)Trails!
                 (O)             
          _______/ \_______       Scott Cox
    

Fellow Noters!  I have received quite a few requests for the following article
on cyanoacrylate glues.  What follows is excerpted from an article entitled
"secrets of the Superglues", by A.J. Hand which appeared in the February 1989
issue of Popular Science.


SECRETS OF THE SUPERGLUES  -  by A.J. Hand

"Serendipity played a starring role in the discovery of superglue.  During
World War II, its inventor, Dr. Harry Coover (now president of Loctite Corp.'s
new business development group) was a young chemist working at the Kodak
Research Laboratories in Rochester, New Yoprk, looking for an optically clear
plastic for gun sights.  'I was working with some acrylate monomers that showed
promise,' he relates.  'But everything they touched stuck to everything else. 
It was a severe pain.'"

"1951 found Coover supervising a group of chemists at the research laboratories
of Tennessee Eastmen Co.  Their mission: to find a tougher more heat resistant
acrylate polymer for jet canopies.  One of the group, Dr. Fred Joyner, spread a
thin film of ethyl cyanoacrylate between a couple of prisms of a refractometer
to check its refractive index.  He made the measurements but couldn't pry the
prisms apart.  'It was then I suddenly realized thet we had a unique adhesive.' 
Years of work remained before cyanoacrylate became a viable product.  Eastmen
910, an industrial adhesive was introduced in 1958."

"Cyanoacrylates are reactive monomers that polymerize (chemically link) when
pressed into a thin film - and onlyu then.  Under normal conditions all
surfaces have at least a monomolecular layer of water on them.  It's actually
the water, or any weak base, that is the catalyst causing the polymerization."

"The original cyanoacrylates were water-thin and good for gluing nonporous
surfaces only: metal, glass,rubber, and some plastics.  Later, thickeners were
added by some companies to adapt the adhesive for wood, leather, ceramics, and
such."

"All cyanoacrylates bond flesh well, as nearly every user knows.  This
generally causes no problem, for acetone (lacquer thinner or nail polish
remover) will dissolve the glue.  But beware of tots bearing superglue.  A
medical journal recently described the case of a man who had to have a plug of
cyanoacrylate surgically removed from his ear.  It seems his three year-old son
squirted in a glob of glue while daddy slept!"  (Did his son live to four? S.C.)

TROUBLE WITH CYANOACRYLATE

"The problems most people have with cyanoacrylates are tame by comparison: 
merely poor or failed bonds.  Shy does this happen?"

"There can be many reasons.  Sometimes the trouble starts in the plant.
Inferior drugstore cyanoacrylates often ore of poor quality to begin with. 
Most are imported from Japan or Taiwan, where producers don't spend enough time
in refining."

If cyanoacrylate isn't properly prepared, it will have a short shelf life.  So
the makers of the low quality stuff add excessive stabilizers to keep it from
curing in the tube.  The result is poor performance.  The stabilizers are
acidic materials.  If the concentration is too high, it will overcome the the
catalytic effect of the minute amount of moisture on the substrate and nothing
will happen."

"good CAs - used properly...are used every day by hundreds of different
industries.  Museums soak brittle bones and fossils with the glue; it helps
bind them together and give them strength.  Burt Rutan used CA extensively in
the construction of the Voyager, the lightweight airplane that flew around the
world."

"CA can have a tensile strength of 4,000 to 5,000 psi, or roughly four times
that of white oak.  For all practical purposes that's overkill."

USE IT RIGHT, TOO

"Getting good results is more than a matter of buying a quality glue, however.
You also need the righr formula for the job you're doing, and you have to use
it correctly.  Rule one is this: Don't expect the water-thin CAs to do every
job.  The gap filling is directly related to the viscosity.  You use the
water-thin products on parts that are smooth, tight fitting, and relatively
non-porous.  These glues set fast; so when gluing a joint you must assemble the
parts dry, then apply the adhesive around the edges of the seam.  It wicks deep
into the joint by capillary action and cures in seconds."

"Because these CAs are so thin, they will not wick into loose joints, and they
won't bridge gaps.  They're not much good on porous materials either.  They get
soaked up before they can wick throughout the bond area."

"That's where the higher-viscosity formulas come in.  Makers offer medium
viscosities (like syrup) and thick glues (like a mixed epoxy).  These are
thick enough to bridge small gaps and to resist being sucked into the joint. 
You apply them to the surfaces first, then assemble the joint.  Consequently
they have slower cure rates.  The thickest usually take a minute to cure."

"But if you are using them on sloppy joints with wide gaps to fill, cure time
may extend to minutes or even hours.  This is one case where the spray on
accelerators are indespensible.  Just mist a light coat on one of the mating
surfaces.  It will dry almost instantly, but remain active for several minutes. 
Apply your glue to the other part then assemble the joint.  The accelerator
will kick the glue over in seconds."

STICKY BUT TRICKY

"Cyanoacrylates are odd beasts.  So sometimes, despite your efforts, you  may
still have problems with them.  Common causes are:

1.  Poor fit.  Even though thick formulas ccan fill small gaps, the better the
fit the better the bond.  Always check mating surfaces before bonding.  Smooth
them up and remove any burrs aor rough spots.  Kickers help, but it's best to
aim for a good fit in the first place.

2.  Too much glue.  Never use more than necessary.  Optimum results are
obtained with the minimum quantity of adhesive required to fill the joint.  In
general one free-falling drop spreads over one square inch.  It takes some
experience to know how much glue is enough so its a good idea to experiment on
scraps of your material.

3.  Premature curing.  Do not spread your glue before you assemble the parts. 
This encourages it to start curing.  Instead, lay down a serpentine bead, then
assemble the parts, letting pressure spread the bead out inot a thin film.

4.  Premature stressing.  Although CAs cure in a matter of seconds, this
initial cure is only about 20 percent of full strength, which is reached in 8
to 24 hours.  Give the bond ample time to cure before subjecting it to much
stress.  (here's where I find building dry in a jig then zapping the joints
really takes advantage of the properties of CA. S.C)

5.  Surface contamination.  CAs are more tolerant of this than most glues, but
they still work best on clean surfaces.  Waxes, oils, and excess moisture can
act as barriers between glue and substrate, and this can lower bond strength.

6.  Acidic surfaces.  Since alkalinity triggers the cure, its not surprising
that acidity inhibits it.  To solve this problem, you can use a kicker on one
of the mating surfaces.  Kickers are organic amines that supply a heavy dose of
alkalinity.

7.  Low shelf life.  Store unopened bottles in the freezer.  Frozen, the
adhesive will last at least two years.  Once the bottle is opened, however,
shelf life drops to about six months.  Moisture in the air gets in, starts the
curing process and the glue gets progressively thicker until its too gummy to
use.  Experts do not recommend refrigerating or freezing bottles that have been
opened.

8.  Cold.  Users who store it in the fridge or freezer may take it out and use
it cold.  They apply it as usual, and the joint simply falls apart.  What
happened?  The polymerization is not terribly sensitive to cold but when the
glue is colder it is thicher, and it may not get squeeded into a thin enough
film to expose it adequately to the surface moisture it needs to catalyze."


Well there you have it, fellow noters!  A fascinating topic and one that will
generate many more tips and techniques from those of us with a heavy CA habit.

                --|--             Happy (con)Trails!
                 (O)             
          _______/ \_______       Scott Cox

    

    The article said that "Experts do not recommend refrigerating or
    freezing bottles that have been opened."
    
    Why is that?  Besides the problems of trying to apply it cold,
    wouldn't freezing extend the shelf life even though air has
    begun to attack it?
    
    Glenn

    Jim,
    	The throttle cable may have come loose because the epoxy didn't
    bond properly to the plastic.  Try roughening it up with sandpaper.
    I always do that wherever I plan to glue the cable tubing in place.
    I use CYA or epoxy with good results that way.  If you already glued
    it in, make sure that it is really stuck this time.  Often there
    is a film of something on the outer surface that prevents a good
    bond.
    
    Charlie
    

    Glenn,
    
    I can't speak to the "experts" who were quoted in the article but
    I, personally, have been refrigerating my CYA's for years with no
    ill results.  I've never frozen it, however.  Years ago, while working
    at GE Computer, we used Eastman-910, one of the very first CYA's
    and, according to the mfgr's instructions regarding use, handling
    and storage, we kept all unused as well as all opened adhesive in
    the refrigerator to prolong its shelf and useable life.  After losing
    unknown dollars worth of hobby CYA's, I remembered how we handled/
    stored the Eastmean-910 and began keeping all my CYA's, epoxies,
    etc. in a small, office-size refrigerator I bought for the workshop
    and my glue expenses returned to the nominal level they _should_
    be.

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    re: .46
    
    Freezing the CYA is the recommended method of extending shelf life,
    though that depends on what kind of shelf life you are looking for.
     Refrigeration does help and is the prefered method if you are using
    the adheasive at a steady pace.  If you find that you go long periods
    without using it you should place it in the freezer.  The freezing
    temp of CYA is considerably less than your freezer will attain so
    the CYA doesn't solidify.  Upon removing from the freezer allow
    about 30 min to an hour for the adheasive to 'warm' up.  I have
    kept an opened bottle of CYA in fine shape for a year by freezing,
    so it does work.
    
    
    jim
    

    What about an unused bottle?  Should I just leave it on the shelf
    or stick it in the Freezer?
    
    Ken

    even unused bottles will benifit a good chill.  At least so I've
    been told.  Even the manufacturer suggests that the bottles be kept
    cool to cold at the hobby shop untill sold.  I know of severl that
    do this.
    
    jim
    

        Re:< Note 409.49 by TUNER::FLIS "Let's put this technology to work..." >

                CA gone  bad  is easy to recognize, it has a funny thick,
        crystalline  consistency, will  set  slowly  and  create  a  hard
        curface instead of penetrating.  I was unlucky to get a couple of
        bottles of bad CA once from a store.
        
                      _ 
                     / |
        |  _====____/==|
        |-/____________|
        |    |        o \
             O           \ 
                          O
         Hang in there! o_|_
                          |
             Anker      \_|_/

    Re: .-1,
    
    Egg-zackly!  I have a small Sanyo (I think) 2-cu.' office refrigerator
    in my shop for the sole purpose of storing CYA and epoxy products.
    (Of course, it'll also accomodate a can or three of Colorado Cool-Aid.)
    ;b^}    

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

    Al,
    	Just be careful when grabbing one of those Cool-Aids that you don't
    get 5 minute epoxy.  I'm afraid my building would go down hill in a 
    hurry if I stocked my shop with the stuff.  Boy could I go for a cool
    one about now - 5:15 on a friday afternoon - Have a good Weekend
    
    Charlie
    

    I have a joint that I intend to epoxy so I will have plenty of time to
    maneuver it before the adhesive sets.  Once the pieces are positioned,
    I need to freeze them in place while the epoxy sets, and they do not
    lend themselves well to clamping. 
    
    Question: Can I use instant CYA as a clamp?
    
    In particular, can I 
        
      spread the epoxy (leaving a couple of bare spots for the CYA later), 
        
      then position the parts (squishing the excess epoxy in the process),
        
      apply the CYA on the intended spots 
           (almost certainly having the CYA wick onto some uncured epoxy)?

    Or will the CYA react in an unpleasant way with the epoxy?

I tried that once a couple of years ago and got a smoke reaction
-- the joint got very hot.  Never tried it since.  At the time I
was living in Silicon Valley, at sea level, and CYA often kicked
off hot -- also, that was while I was still using thin stuff for
my general building.

If you do try it let us know. 

	re: .55

        I believe epoxy resins contain amines. These are the same
        chemicals referenced elsewhere as the active ingredient in CYA
        kicker! No wonder it got hot on you! 

        I do it the other way. I tack the part in place with the CYA. Let
        that dry for a bit, maybe for a long time. When I'm ready, I
        fillet everything with epoxy. I don't know how well the epoxy
        sticks to the CYA, so I don't slobber extra CYA around. This
        leaves as much wood available for the epoxy as possible. I've
        never had any problems with the joints coming apart, the materials
        (balsa or plywood) fail first. This assumes a good epoxy (NOT the
        5-minute junk!) 

    Al, as I said at Puckerbrush, the crash was not your fault, but simply
    part of my learning process.  As Al said, the wing was totaled and I
    entered an order with Tower this morning ($21.50).  I should have it 
    in the next 3-4 days and about 2 nights to assemble and another 2 nites
    to cover and I'll be back in business. 
    
    As Al mentioned, I was very upset to see so many glue joints not bonded
    as I would have expected.  I will make sure this time, the bonds are as
    they should be.  Al mentioned that in the past, he has barely moistened
    the joints with a water-dipped Q-Tip prior to application of CA.
    Anyone have any other hints that would be useful?
    
    When I got back to my daughter's house, I removed the carb, head and
    back plate from the engine and cleaned out a lot of crap, but all
    in all the engine appears to be O.K. All servos and rcvr are fine.
    We didn't get back to Colo Spgs until 12/30, so I haven't had a chance
    to fire up the engine yet.
    
    With about 10-12 hours on the PT 40 and this being the first really
    damaging crash, I don't feel too bad.  At least I'm learning.
    
    Happy New Year to all, Chuck
    

Unless you're hypersensitive to weight, I wouldn't go sparingly on
the glue. Certainly a PT40 is not a flyweight type plane, it should
be built rugged. I recommend to NOT use hot CA for gluing ribs to spars,
use the gap filling CA. The hot stuff is so thin it sometimes soaks 
completely into the wood, leaving very little at the joint. Thicker
glue will leave a small fillet of glue that adds a lot of strength.

The only place to possibly be careful about too much weight is the
tail feathers - they're far from the CG and the weight is multiplied
by the distance, so you might have to add nose weight to compensate
for a tail heavy fuselage. Some kits are susceptable to being tail
heavy, I don't remember if the PT40 is one of them. Also be sure to
balance the wing left-to-right, again by adding lead weight to the
light wingtip (glue it in well with epoxy). This should ideally be
done after covering, but if you aren't sloppy with the covering it
should be ok if you balance it before covering. Actually, to be best
you should balance the entire airplane, including radio, engine, prop,
muffler, and empty fuel tank. Balance it forward-and-back for the
correct c.g., and left-to-right to the centerline of the fuselage.

Dave

        Re:           <<< Note 239.1807 by GENRAL::BALDRIDGE "Fall has fell" >>>

        Chuck,
        
                I gathered  from  Al's  message  that the ribs were glued
        onto the spars  with  thin  CA.    As far as I remember the PT-40
        spars are hardwood.   My experience is that you need thick CA for
        a balsa/hardwood joint.  The  balsa/hardwood  joint does not make
        actual physical contact in many places  and  thin  CA is so runny
        that you don't fill the gaps.  I use thick Ca and use a few puffs
        of kicker if the gap is really wide or it doesn't set immediatly.
        
                Being  an  instructor  brings  you  into  the dilemma  of
        relieving  the  scarcity  of instructors, but having to take  the
        responsibility and grief this may bring you personally.  There is
        one  particular  individual who keeps reminding me that a crashed
        his plane.    But  if  you  can  take  it,  and I can, its really
        rewarding.  It  does  really hurt when a student's plane comes to
        grief, no matter how it happens.
        
        Anker

Chuck, too bad about that PT -- but look at the bright side: you
get to fix that wing servo mounting!

Far be it from me to give advice, but on the other hand, I do
know something about fixing up after a crash.  Up here, I find
thin CYA nearly useless because of the combination of dry air and
its intolerance of less-than-perfect fitting joints.  Get the gap
filler stuff, its a lot easier on the nerves if nothing else. And
be sure to kick each joint.  Al's method of wetting the joints
before gluing is something I'm going to try.

Also, I make it a practice of going back over every joint in the
wing and pulling on it for test prior to covering.  I usually
find 2 or 3 that need re-doing.  Be careful of cracking a rib
while you're doing this: you should apply enough force to each
joint to run this risk. 

    Re: 1809,10,11 Thanks Dave, Anker & John.  After writing .1807, I got
    to thinking about those incomplete joints and realized the adhesive
    had soaked into the balsa ribs, leaving nothing to hold on to.
    John is exactly right about our low humidity environment here in
    the Springs.  All CA's work much better in a higher humidity, which
    is why Al's moistened joint idea would work. 
    
    Dave, the PT40 is VERY suseptable to being tail heavy.  In my case
    I had to add over 5 oz. of lead to the nose under the engine mount to
    get it to balance right.  I was able to add a couple of wood screws
    to the light wing tip, before covering, and side-to-side balance did
    not change after covering.
    
    Chuck
    

    Re: last several,
    
    Perhaps I should explain the theory/logic behind wetting a glue joint
    prior to hitting it with CYA.  Up front, I'm no chemist but, as I
    understand it, CYA requires the minute bit of surface moisture that
    exists on most things (certainly on fingers :B^) ) to catalyze/kick the
    adhesive.  That's why (though this situation is probably unknown in
    areas outside the southwest) CYA sometimes won't kick in especially dry
    situations on on wood that's extremely hard (contains little/no
    moisture) or is particularly dry.
    
    Pre-wetting the joint accomplishes [at least] two things: 1.) It
    artificially provides the moisture required to kick the CYA, and 2.) It
    tendes to swell the wood enough to make a tighter joint and the
    expanded cells in the wood can accept the glue more readily.
    
    I believe this method to be superior to using kicker as it's my belief
    that kicker tends to cause a flash cure on the surface and actually
    defeats penetration of the joint.  Also, (and I've verified this with
    Frank Tiano of ZAP) I believe a "kicked" joint tends to be more brittle
    than one that is allowed to cure naturally.  My old kit box(es) full of 
    scrap balsa (doesn't everyone have at least one of these?) contain some 
    pieces that approach 20-years old and, being stored in the shop attic,
    they've had plenty of opportunity to become plenty dry...that's what
    prompted me to start suing the wetting method described.  I just
    reasoned the situation out based on the little knowledge I had of the
    glue type but I don't imagine the idea is necessarily original. 

      |
      | |      00	 Adios,      Al
    |_|_|      ( >o
      |    Z__(O_\_	(The Desert Rat)

I tried a home-brew kicker that didn't work, based on some ideas
I had heard. I just mixed some baking soda in water and put it
in my empty bottle of kicker (the bottle was empty, I didn't
want to make a trip to the hobby shop).

It doesn't work. Makes a mess. The surface of the glue seems to
harden slightly, but it doesn't kick the rest of the glue like
"real" kicker does.

I haven't tried using raw baking soda as Dan suggests.

Dave

Found this on the UUCP net.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

From: tswift@well.UUCP (Theodore John Swift)
Subject: Re: Construction techniques?
Date: 13 Jan 90 00:31:49 GMT
 
 
 
>I am now building a CG Super Chipmunk and have just
>completed sheathing the bottom half of the wing.  I used
>slow setting cynoacrylate here and lots of masking tape.
>What I don't look forward to is sanding where I had to butt
>glue pieces of sheathing on the wing surface.  The
>cynoacrylate causes the balsa to come off at different
>rates.  Which brings up my question...(sanding wing sheets)
 
A guy representing the PIC line of cyanoacrylate "products" gave a demo
at our club (Pioneer R/C, Santa Clara, CA) meeting a few months ago.  He
showed the advantages of different adhesive viscosities, accelerator spray,
etc, etc.  One of the cute tricks he reveiled (there were several) may
solve your problem:
  Apply some CA debonder to your block of sandpaper, then carefully sand
as usual.  The debonder gives the sandpaper enough of an advantage over the
CA that it cuts the CA about the same speed as the balsa.  Unfortunately,
I can't give you a more detailed description; maybe someone else here has
a better memory.  Vic?
-- 
Ted Swift                        "Why is there a watermelon there?"
{hplabs,lll-crg/lcc, pacbell}               "I'll explain later"
               !well!tswift             - from "Buckaroo Banzaii"

    I have a question about CA glue that I didn't find anything about while
    reading note 409.  My question regards the effect of the fumes from
    this glue over an extended period of exposure.
    
    Last night I assembled the two wing halves of my Eagle 2 using
    primarily ZAP CA, then some ZAP-A-GAP to make fillets after the regular
    CA had hardened.  I was aware of the fumes, but not uncomfortable, and
    worked about 4 hours without a break.  My basement has no ventilation
    so I was breathing the fumes all the while.  I went right to bed after
    finishing up, and didn't notice anything more than a mild eye
    irritation, but this morning when I got up I felt drugged.  Its 1:30
    PM, and I still feel woozy and uncomfortable.
    
    Question;  Did I get an overdose of CA fumes?  What are the long term
    effects, if any?  What are the precautions I should take to avoid this
    in the future?
    
    Any help on this will be appreciated.
    
    Thanks,
    Joe

>    I have a question about CA glue that I didn't find anything about while
>    reading note 409.  My question regards the effect of the fumes from

Don't even know what is in 409.* but 11.201 is a list of "Safety" related
issues and it points to note 862.* amongst others.  Start out reading
862 and it's replies.

>    Question;  Did I get an overdose of CA fumes?  

Most likely - it effects different folks in different ways.

>What are the long term effects, if any?  

Permanent and irreversible sterility :-)

>What are the precautions I should take to avoid this in the future?

Consider (1) wearing a mask, (2) adding a vent fan to your workshop,
(3) switching to the more expensive but seemingly less toxic UFO brand
of CA's.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    
    The only published problems with CA that I've seen are when people
    have allergic reactions to them.  You might be mildly allergic to CA,
    in which case Kay's suggestions should help.  As with anything that
    puts out fumes as (ob)noxious as CA fumes, I personally try to get
    as much ventilation to the area as possible, even though I've "only"
    had eye irritation from CA fumes.
    
    Bill

  FWIW - Balsa USA sell UFO for $7.95/50 gram bottle.  A great deal as most
places want $10 (mail order) to $15 (hobby shop) for that size.


              Jim  (who thinks the regular CYA started my asthma attacks
                    and has had no problems with UFO)

John Preston's Safety column in Model Aviation has addressed the
effect of CA fumes several times.  As the previous replies have
stated, there is no evidence of any toxic effect of CA, either
over the long run or for short term (Kay was kidding about
sterility).  The effects of sticking body parts together are
apparently the worst hazard of the stuff.

I don't know what caused your wooziness today -- were you
drinking while you worked (that's my joke, but boy, do I have a
story about that one! Its incriminating though.)?

The UFO that was referred to stands for User Friendly Odorless, a
new type of CA that has no fumes (but emits odorless cyanide gas
-- another of my jokes).  Anyway, it has been given rave reviews
by people who are sensitive to CA's fumes, and you should try it
if its a big problem for you.  UFO has an additional advantage in
that it doesn't react with certain materials like foam, which
does react with ordinary CA.  Its slightly more expensive though.

    One thing I read a while back, was the effect of heat on cya.
    Electronic components are sometimes glued to the board with cya prior
    to soldering. Apparently workers were affected by fumes. The report said
    the cya breaks down with the heat giving off traces of cyanide gas.
    
    Before I knew this, I did just that, getting pretty close while I was
    soldering as the operation was delicate. Felt real strange a long time
    afterwards - never again.
                 
    Mark

    This is probably more than you care to know about Cyano's, but
    anyhow - this from the Chemical Dictionary by G.G. Hawley.
    
    cyanoacrylate adhesive, based on the alkyl 2-cyanoacrylates.
    It describes a class of materials prepared by pyrolyzing
    (pyrolysis=a heat reaction) the poly acrylates that form 
    when formaldehyde is condensed (mixed with cyanoacetates).
    The adhesives formed have excellent polymerizing and bonding
    properties, in fact a polymerizing inhibitor is usually added
    to prevent premature polymerization.
    
    A typical formula would be methyl-2-cyanoacrylate or:
    CH/2:C(CN)COOCH/3
    Notice the (CN).  This is the Cyanide radical, what really 
    gives it it's desirable (and undesirable) properties.
    The CN breaks apart giving off Cyanide gas.  Published
    toxicology tolerance TLV (Threshold Limit Value) ranges 
    from 0 to 2ppm (parts per million) depending on what you
    read. (i.e., OSHA, ACGIH, etc.).
    
    The bottom line is; you shouldn't inhale ANY.  Some people
    become "Sensitized" to certain chemicals.  It has been shown
    that a sensitized individual can initiate a reaction with as
    little as 2 molecules (thats MOLECULES, not ppm) of exposure.
    Others can get by with a lot more exposure.  I personally am
    not significantly affected by the fumes..but then..)
    
    Anyhow, I think that this all pretty much agrees with all that
    has been said so far.  BE CAREFUL,,,DON'T INHALE FUMES.
    
    john
    

    Reading the last few replies concerning cyanide gas given off when
    cyano glues are heated raises a question maybe we should all consider.
    If we were to have a house fire, and there are 3 or 4 bottles of
    cya around, wouldn't this present a hazard to the firefighters?
    Should there be a warning to wear masks?  Or is the amount of cyanide
    gas too little to create a hazard?
    

    Is it a hazzard to the fire fighters??  Yes, I imagine it would be.
    
    Is it the only breathing hazzard to a fire fight??  No.  All of the
    plastics and synthetics give off all sorts of fumes when burned.
    
    Should there be a warning to wear masks??  I believe that any
    firefighter entering a burning house is required to be wearing 
    self contained breathing apparatus (SCBA).  Generally, they will wear
    this equipment until after the fire is out and the house is being 
    vented...
    
    But a call to the local fire department would certainly confirm 
    these answers...
    
    cheer,s
    jeff
    

.According to an NFPA fire protection manual it is a class 2 health risk in a 
fire standard issue breathing apparatus provides protection. The small amounts
we keep on hand would be a minor hazard compared to the acrylic carpet or PVC 
pipes which rate a 3 and 4 respectivly. 

-j

    BTW, I meant to add that Greg Namey sent me a sample tube of PFM and we
    used it to attach the bubble canopy on Bob Frey's Top-Flite P-47
    warbird racer.  Thus far, I'd have to say it stands up to its
    advertising except that we didn't find that it was as readily
    removeable as claimed.
    
    The best I know, Zap-a-dap-a-goo is Pacer's answer to PFM and is
    a similar-to-identical product.  The F-Troop guys over in California
    have been raving about Z-A-D-A-G in the last couple of "F-Words"
    (their newsletter)...from what they've described, I'd haf'ta say it
    sounds exactly the same as PFM.
						 __
				|      |        / |\	   	       
      	         \|/		|______|__(o/--/  | \	   	       
      | |        00	       <|  ~~~  ____ 04 ---- | --------------------
    |_|_|        (O>o		|\)____/___|\_____|_/	   Adios amigos, Al
      |     \__(O_\_	        |	  |___/	 o	   (The Desert Rat)

    I recently read somewhere (MA Saftey col.?) that the Zap-a-dap-a-goo
    is highly flammable where the PFM stuff won't burn even with a flame
    touching it.

    Personally, I'm going to buy some PFM.

                       _____
                      |     \
                      |      \                          Silent POWER!
      _        ___________    _________   |            Happy Landings!
     | \      |           |  |         |  |
     |--------|-  SANYO  + ]-|  ASTRO  |--|              - Dan Miner
     |_/      |___________|  |_________|  |
                      |       /           |     " The Earth needs more OZONE,
                      |      /                       not Castor Oil!! "    
                      |_____/

    The blurb in the MA safety column says that Automotive Goop is
    flammable but PFM isn't. PFM contains toulene, so I don't know why
    it wouldn't be flammable, at least until the toulene was evaporated.
    
    I like PFM, flammable or not, and since when has using flammable
    materials in modeling been such a big deal ?
    
    I bought a tube of Automotive Goop a few weeks ago because the price
    was $4 and the description  on the tube looked the same as PFM.
    I haven't opened it yet, but tonight I will try it and PFM for
    flammability, fresh out of the tube and after ~ 1 hour cure time.
    
    Also will check for odor, adhesive properties, removability and
    anything else I can think of.
    
    Terry

    I've used Goop and it stinks while drying. I wouldn't recommend it
    indoors without ventilation. Must be the toulene. Sure smells
    flammable. I haven't used it alot in modelling but it hold pretty well
    in the greasy, vibrating car environment as well as holding things in
    place in video games. I've used it to hold magnets and yokes on game
    monitors after I've adjusted them (read - broken them loose ;^). Cures 
    to a rubbery consistancy.

    I'm not a chemist but I play one in R/C notes, and here is what
    I found in my PFM vs. goop comparison:
    
    PFM does not contain toulene but Goop does. Unlike Jim, I can't
    smell either one unless I put my nose right down on them.
    The longer they cure, the more they smell alike. After 14 hours
    it's impossible to distinguish between them.
    
    Flammability:
    Using a kitchen match as a flame source, PFM doesn't burn, period.
    Fresh out of the tube, Goop instantly ignites with a bright yellow
    flame and greasy black smoke. As it cures and develops a skin, it
    becomes harder to light. After 14 hours it would burn only if the
    uncured inner core was exposed. It takes ~24 hours to fully cure.
    
    Appearance, feel, spreadibility: virtually identical between them.
    
    Bond strength: 1/8" pine dowels with a 1" overlap joint; after 14
    hours could not separate without breaking dowels. Couldn't pry apart
    with Xacto blade without splitting wood. Same results on both brands.
    
    Once the toulene has evaporated from the Goop, they seem to be
    identical substances.
    
    Note: PFM can be thinned with toulene, it would then be flammable.
    
    Conclusion: $9.95 for 3.7 oz. of PFM.  $4.00 for 3.7 oz. of Goop.
    
    Terry

This Goop stuff sounds a lot like the stuff runners put on the
bottoms of their shoes to prevent or fix wear spots.  I think its
called Shoe-Goo.  Kind of an amber color, as I recall.  The price
is about the same too.

I recently got suckered by a product called, I think Lexan.  What
happened was that I was having problems with screws vibrating
loose, so Phlyin' Phil recommended that I coat the screw with
silicon before installing it.  I went to the store and in the
silicon section found this stuff -- Amazing Space Age
Discovery!!

Well, when I got it home and opened the container, it turned out
to be nothing more than disguised model airplane cement, with
some kind of rubber added to give it consistency.  I cannot count
the times over the years when I've bought some "amazing product"
and only found it to be good ol' model airplane cement.  I have
to admit however, that it works like a charm in keeping the
screws in place, guess I shouldn't be so hard on it.  I even used
it to plug a leak in my roof...which is what its made for.  Aw, 
what the heck, its great stuff! I'll sell you the rest of my tube
for a song!

    Found it! Ain't keywords wonderful?
    
    I've got to secure some servos to a demonstration plane for CMRCM. I
    was wondering how the "Goop" worked out. I'm looking at either Goop or
    a Sylicone chalk to attach the servos. This is for a non-flying demo
    plane to shoe a radio installation. Double sided tape didn't work well
    enough on the plexiglass.

    
      Jim,
    
         PFM is another alternative. It holds servos securely and is
    removable afterward. If you bring the demonstrator tonight, I could
    bring some PFM, and we could mount the servos at the meeting
    
    

    I got some clear silicone last night and glued them in. The radio
    owners will be pleased to note that this stuff peels off nicely once you
    break the servo loose. I wanted to get some of it done but fell asleep
    on the couch instead. I've got it with mme and will bring the labels
    and such also and we can "decorate" it at the meeting.
    
    I was looking for something PFMish but didn't know where I could find
    it on short notice. I knew that my auto parts store carried Goop so
    that's why I asked. As it turns out they were out of Goop so I got the
    clear silicone.

    I picked up my first bottle of CA Kicker this week and gave it some use
    last night. This stuff is worse than the CA as far as fumes. It works
    real well but you almost need a spray booth/fume hood to use it. I
    think I'll probably save it for those field repair emergencies where
    the CA doesn't want to kick and try top stay with the faster CAs that
    set quicker (I got it because this new CA from Tom's is 10 second
    setting). Nasty stuff. Maybe I'll reopen my rendering service and grind
    up some hooves and hide for my next project?

    That's why I do major glueing outdoors, and keep windows open during
    glueing/kicking sessions to minimise accumulation of who-knows-what
    vapours. I should use a fan to force a draught when there is no wind.
    
    Of course, if you are holed up in a window-less basement, yer' outta
    luck..
    
    ajai

    Jim,
    
    What brand of kicker is this ? I use Zap kicker by the gallon, almost.
    When you build with CA in humidity levels of 5-10%, even instant
    CA just lays there and looks at you. 
    I haven't noticed any adverse physiological reactions yet, at least
    not any that can be separated from advancing age, ;^) . The smell
    isn't attractive for sure, but isn't noticeable ~2 ft. away.
    
    Luckily I've never had any problems with CA/epoxy sensitivity over
    the years but do use rubber gloves when doing large batch epoxy
    jobs.
    
    Terry

    I've never had any problems with CA until early this year. I guess
    over time, I've developed a pretty severe alergic reaction to it.
    If I get a couple of wiffs, my sinus's fill up for a couple of day's
    and my nose runs like a faucet. My last encounter was even worse. I
    got a good dose that time and along with my mead filling up, so did
    my lungs. It was difficult to breath and I ALMOST brought myself to
    the hospital.
    
    It's taken a couple of years to become this sensitive, but I really 
    have to watch it now. I have about a quarter of a bottle of CA left
    and then will be switching over to the odorless UFO stuff to give
    that a try. Everyone should be VERY carefull with this stuff.
    
    
    Steve

    Re: the last two notes
    
    My basement is very damp for most of the year, only being dry in the
    winter, but extremely damp in the summer.  I have found that ZAP kicks
    at different speeds in a given evening, and its a mystery to me that
    even in the summer, it sometimes won't kick.  For example, last night
    while gluing some wing parts, I noticed that on some joints the fast 
    CA would kick immediately, and on other joints it would sit there in 
    liquid state for minutes.  WHat gives?  I have to resort to Kicker all 
    the time when this happens.  Can anyone explain why CA acts differently on
    different joints?
    
    BTW, there's one substance on which CA ALWAYS kicks instantly....you
    guessed it, human flesh. :-)  Must be the moisture in the skin that does
    it.  Sure wish balsa wood acted like this.
    
    -Joe, frustrated by a high-priced product that gives inconsistent
    results

    >>>Must be the moisture in the skin that does it.
    
    EXACTLY right. Which is also why CA won't kick as fast in really dry
    conditions or really dry wood. Humidity plays a big part in how fast
    CA will kick. In places like Arizona, I think I read that people will
    actually put water on the wood to be joined (moisten the area) before
    applying CA.

    Yeah, I've noticed it too. I haven't started my dehumidifier yet so my
    basement humidity is probably better than 50% these days. One thing
    that I used to do that worked pretty well was to dip the piece to be
    joined in baking soda (just the end where the glue was going) and it
    would kick faster. I'll probably go back to that in the future. That
    way I just have to watch out for the CA fumes.
    
    The kicker in question was Zip Kicker (or is it Zap?) I did hear from
    another modeller that the Bullet brand CA just gel'd with their kicker.
    The bad habit I used to use was to touch the joint with my finger to
    start the reaction. Once started, it continues. If you're slow, you're
    attached.

    re past couple...
    
    I am begining to wonder if lack of ventilation during winter building
    sessions (can't open window - if there is one - as heating bills will
    go up) is the culprit. Steve?
    
    Regarding the different kicking speeds - my observation has been that
    wood that has been [over]sprayed with kicker, either deliberately or
    indirectly while glueing some other joint, will set the CA faster, even
    if you had sprayed the wood being joined some days ago.
    
    ajai

    Wood density can affect kicking speed too. It's most noticeable
    with instant CA. If the wood is dense, the CA can't wick out into
    it (less capillary action) and puddles up on the surface. 
    This inhibits the kicking speed, since the greater the surface area
    of CA exposed to the air the faster the kick.
    
    Wetting the wood to promote kicking in low humidity can be
    counterproductive. If it kicks too fast, there is no penetration
    into the wood, resulting in a weak bond.
    
    Spraying with water from a perfume atomizer will work too, and you
    can let the CA set for a moment to penetrate before hitting it with
    the water.
    
    Terry

I like the smell of Zap Kicker.  I understand they have come out with
a new version that is not harmful to the ozone layer and I'm sure I
have the old stuff because I buy the large refill bottles - but
no kidding - I find the stuff quite pleasant - go figure.  I do have
a hard time with thin Zap itself or when sending Zapped pieces however.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

    Well, last night I got back into speed building mode and finisher up
    the other panel on my wing. I found a good use for the kicker that made
    life a lot easier. I sprayed the CF laminate with kicker and
    thenpressed it onto the CA coated spars. It kicked and stuck very
    nicely. The night before I found that the laminate was sticking to my
    fingers before it stuck to the spruce spars and I had a lot of grief
    with it. The smell is pleasant but the efeect of breathing it is a
    little disconcerting (or I'm coming down with a stomach flu this week)
    
    Join the halves and sheet/cap strip and cover and I'll be back in the
    air on sunday

    
    
    		I think I know what it is about Zap Kicker that's
    	soooo pleasing; it's that ole' smell of bubble gum that
    	most of us were so fond of as kids. At least that's what 
    	it reminds me of. Hope they don't change it because that
    	makes building so much more fun !
    
    		As far as kicking speeds go, I've found that when
    	your using C/A with or without kicker, ventilation of some
    	kind seems to make it set faster, especially if your not 
    	using kicker. I use a small boxer fan set in the corner of the
    	bench to keep a breeze going. Makes the glue fillets hard
    	as a rock in no time.
    
    
    	Carl

        I've heard that the new ozone friendly kickers don't work as well
        as the old stuff. I still have lots of old stuff myself, so I
        can't say for sure.

    
    I have a bunch of questions reagrding CA and Kicker.
    
    1) Even though UFO is friendly to yopur nose is it just as dangerous
       to inhale. If so then that's bad since your nose can't tell when
       your in trouble.
    
    2) I have bottle of thin UFO and suddenly in the past couple weeks
       it turned THICK !!!. Could mixing my caps with thick and thin
       case this?
    
    3) I had a bottle of Sattalite City ZIP kicker and it worked extremely fast.
       Sometimes even got smoke !!!. I ran out, then bought PACER ZIP kicker
       and it's extremly slow, smelly and spits out brown stains sometimes.
    
    		Is this normal?
    
    		Is it a bad bottle?
    
    		Are all new kickers like this now due to environmental safe
                products?
    
    4) Do you people actually spray the wood first then glue?
       I find that impossible to work. I always glue wait for it to
       wick and then spray.
    
    5) Some kickers say they are environmentally safe.
    
    		Safe to you?
    
    		Safe to OZONE?
    
    		Safe to what?
    
    		Are they all (have to be) safe?
    
    If some kickers are safer to the environment at a cost to the
    performance of the product. The environment is well worth it
    and I'll be glad to live with it.
    
    Sorry if any of these questions have been asked in previous replies.
    pointers are naturally welcome.

re  questions reagrding CA and Kicker.
    
>>  1) Even though UFO is friendly to yopur nose is it just as dangerous
       to inhale. If so then that's bad since your nose can't tell when
       your in trouble.
    
    No danger.  I'm ultra sensitive to ordinary CA, but I use UFO regularly.
    
>>  2) I have bottle of thin UFO and suddenly in the past couple weeks
       it turned THICK !!!. Could mixing my caps with thick and thin
       case this?
    
    Several things can cause it, namely any contamination of the nozzle
    and/or airborne moisture or kicker fumes getting inside the bottle. 
    It's OK.  It is now the same as thick UFO and can be used accordingly.
    
>>  3) I had a bottle of Sattalite City ZIP kicker and it worked extremely fast.
       Sometimes even got smoke !!!. I ran out, then bought PACER ZIP kicker
       and it's extremly slow, smelly and spits out brown stains sometimes.
    
>>  		Is this normal?
    
    Unfortunately, yes.  At least in my experience as well re smell and stains.
    
>>  		Is it a bad bottle?
    
    No, but the stains do get worse with age.
    
>>  		Are all new kickers like this now due to environmental safe
                products?
    
    Unknown to me.  I have a ten year supply of Pacer that replaced the
    earlier ten year supply that aged.  It sure does stink.
    
>>  4) Do you people actually spray the wood first then glue?
  
    Rarely in my case.  Actually, I don't usually use a kicker.
    
>>  5) Some kickers say they are environmentally safe.
    
>>  		Safe to you?
    
    Safe to me.   But  maybe that's what gave me Alzenheimer's at an early age.
    
>>  		Safe to OZONE?  Safe to what? .....
    
    Unknown.   Write to them and ask.
    
    Alton, on vacation but not flying       arrrrgh.

    
    Thanks for reply. If Satelite City is environmentally equal to pacer?
    Then I think you would like Satelite City Kicker much better than
    pacer. Smells but does not stink, No stains, and kicks faster.
    

What are some recommended glues for joining wood (say plywood or maple) to
metals such as brass? How do they hold up over time (years)?
						-- Tom

I'd recommend epoxy and roughing up the metal surface for good adhesion

    I agree with .107 use a 24 hour epoxy, if it is for any structural use.
    the longer set time the more absorbion into the surfaces you are
    joining. Make sure your surfaces are clean.
     

Thanks for the advice!
						-- Tom

    What's the difference between white glue and yellow (carpenter's) glue?
    
    						Dave()

yellow glue is formulated for wood joints and white glue was originally 
for paper. The yellow glues are more water resistant. I use Titebond 
for all my yellow/white gluing projects.

    I prefer yellow only because I've used it on my carpentry projects in
    the past.  Would it also be the best (white vs yellow) for foam?
    
    						Dave()
    

I use it with foam on building gremlins and glider leading edges all 
the time. In either case, the foam will let go before the glue.

    I was going to be smart and say that the difference was the color. :-)
    
    	I use the yellow Titebond glue on foam often.  
    
    Charlie
    

    BUT... the aliphatic glues are water soluble. I found out when
    operating my Kadet on floats; the moisture caused the parts bonded with
    Titebond to loosen up.
    
    Dave
    

I've also found that they get brittle with time.  I only use yellow
glue where one of the two materials is not balsa, such as ply or
spruce.  I do this because I have had poor luck with CA joints on
non-balsa materials.

    I've had no problems with Titebond on foam for leading and trailing
    edges.  The foam fails before the glue joint.  I refuse to use Odorless
    CYA due to the cost and epoxy is messy and costly also.  I'd stick with
    Epoxy for float planes where you need it to be more water resistant.
    
    Charlie
    

    
    I've been using Titebond also on my leading and trailing edges on the
    Gremlins..... Epoxy I find is not necessary. I only use it for the
    spars and fuse hold down blocks. Haven't had a failure yet.....
    
    George                                                        

I've even been using Titebond on the wing spars and bolt blocks as well. 
I haven't seen any failures yet (the foam is always attached to the wood 
at the crash site)

    A friend of mine just reported from a crash of annother guy's plane.
    The wings folded in flight and when my friend investigated the case he
    found that the guy glued the two halves of the wings together with wood
    glue, no reinforcement or whatever. The interesting thing was that the
    glue inside was still fluid. Conclusion: if you glue foam with wood
    glue be shure that the moisture can dissapear. It will always (I think)
    work if you glue wood to foam, but doubtfull if you glue foam to foam.
    
    
    	Bernd
    

    Good Point!  I've had the same thing happen under masking tape.  When I
    glue on leading edge and trailing edge, I use masking tape to hold the
    wood to the foam.  I've had the glue still fluid under the tape.  It
    will eventually dry but it could take days.  Epoxy sets without
    exposure to air so it is better for large area joints.  However, Epoxy
    won't set properly if the temperature is less than 70 degrees.  The
    cure will be faster if the temperature is elevated above room temp. 
    This can be handy.  I use a heat lamp to speed things up sometimes.
    
    Charlie
    

  Speaking of glues....


  What is the best way of measuring epoxy?  Are the weights of the resin and
hardener close enough to each other to use a balance, or should it be measured
by volume (fl. oz.)?  Currently I just eye ball the amount I'm pouring into
the cup.  It's worked well so far, but I'd prefer a somewhat more scientific
approach.


                Jim

The weights are different in most cases. Some epoxy sets will give you 
the ratio by volume AND weight on the package. I've seen 1:1 bny volume 
and 1.44:1 by weight.

  I'll have to check the package tonight and see if it's listed.  Maybe I
need to pick up a cheap set of measuring spoons (or steal some from the 
kitchen...:^)

    For small amounts I use some plastic injection things (like the Doctors
    have) with a volume of 10 to 20 ccm (don't ask !) 
    The epoxi I use needs a ratio 2:1, therfore the 20 ccm for reisn (sp?)
    and the 10 ccm for hardener. In this way I can mix 1.5 ccm to 30 ccm.
    for larger amounts I use 2 plastic cups with marks on it that I
    prepared before.
    
    
    Bernd
    

Measuring spoons can be had in most of the "everything for a buck" 
departments (like at the Fair)

The only problem is getting ALL of the measured amount OUT of the 
spoon

    
       I have been using exopy to join the wings on my Gremlins, and plain
    ol' Elmers glue for the leading/trailing edges, wingtips, etc. It has
    worked fine, and I have never had a white glue related failure.      
    
      Why Elmers glue instead of tightbond? I can steal it from my kids! :)

    re: Jim C.
    
       Most of the epoxy (or all for that matter) I have used I've have
      mixed 1:1. On all my bottles of hardner and resin there are graduated
      marks on the side of the bottle. I usually look at these to see if
      I'm mixing 1:1 or not. I know it's after the fact but it's at least
      a guide to see if I'm mixing properly.
    
       I generally just put a dab of harder here and the equivilent resin
      there and eyeball it. Then mix..... Voila... 
    
    George

    I use the eyeball method for small jobs and graduated mixing cups for
    larger ones.  Measuring spoons have a problem because a significant
    amount sticks to the spoon.  In a mixing cup, I pour in x oz of part
    one and then add part two until it is at 2x.
    
    Charlie
    

    I now eye ball small jobs and use measuring cups for large jobs. The
    spoons never worked out as I always ended up getting sick.
    
    Couldn't get out of the habbit of licking the spoons when I was done.
    
    Is it Friday yet???????????????
    
    Steve

    Steve,   What's that stuck to your tongue?
    
    No, It's only Wednesday.  Sorry.
    
    
    Charlie
    

And so we don't have to duplicate your research...

Which brands/speeds/components taste better?

  Okay, graduated mixing cups seem to be the best way to go, but will 
*under*graduate cups work also??  I mean...I don't really see why I should
pay the extra bucks for a cup that has graduated from school!       :^)


Re: Steve and spoons....

  Thank goodness you don't have to mix CYA!!! :^*



            Jim - 


  In the immortal words of John Wine:

     'Circle the Indians, the wagons are attacking!'



             or something like that!


  Okay....how do you confuse an HTA???


  

  Lean 3 shovels against the wall and tell him to take his 'pick'!  :^)


  
  Boy I'm glad I'm taking this afternoon off.........

    I've heard of sniffing glue but not ingesting it. :-)  The stuff we
    used to build plastic models with had the best smell and produced a
    nice buzz. :-)
    
    
    C.
    

One of the things I do for skinning wings is to get the clear plastic 
tumblers at the store and slip one inside the other. Pour water into 
the inside one and mark the level in marker on the outer one. Swap the 
inner one for an empty and fill to the line you just made. Pour the 
first glass into the second glass and mark the "double" level. Now 
drill holes in the two lines on the outer cup that will fit the tip of 
your marker and anytime you need a measuring cup for this amount you 
just slip a fresh clean cup into it and put the marker into the hole(s) 
and rotate the cup to draw the line. Works great and you can have 
multiple levels marked on the cup.

    Not a bad idea once you decode the note :-).
    
    
    E.

    Ya sure Jim, I can follow that. Let's see, ya drill a hole in a glass,
    fill it with water till it leaks out the hole, then put a mark on the
    table and drill a hole in another glass. Sounds good to me.
    
    That's as bad as figuring out the mechanics of a "simple" two pole
    switch. It goes like this..........
    
    When a switch is ON ON, it's OFF OFF. Likewise, when its OFF
    OFF, it's ON ON. However if it's ON OFF, it's OFF ON.
    
    I gotta try a different brand of epoxy.........
    

A demo makes it easy.

Steve,

You have to draw a line around the puddle on the table and then match it 
to... oh, nevermind 8^)

    I find that water does not glue as well as epoxy. I usually take a
    semi-opaque measuring cup that is graduated by a mold in the factory. I
    then add equal parts of epoxy and stir.
    
    The cups cost about 1c each and are considerably cheaper than the
    pencil, drill and drill bit that is needed to produce copies of these
    little beggars.
    
    Also just lining up and matching the level in two cups would be easier
    than marking one tapered cup twice to get equal layers of epoxy. The
    epxoy will certainly dull the end of the pencil which will need to be
    sharpened. If excess epoxy gets into the the sharpener it could jam and
    blow a fuse. If the fuse does not blow the wiring could overheat and
    lead to an electrical fire that would destroy your house.
    
    Far better to purchase pre-gradated cups. After all they should be
    smarter if they have already graduated!. :-) 
    
    Eric on a Wednesday... 
                                                

    I use the pre-graduated cups in 1/4 oz increments.  My smallest batch
    would be 1/4 oz each.  I fill to 1/4 oz with part 1 and then fill up to
    1/2 oz with part 2.  Only uses 1 cup and you get equal amounts.  Only
    problem is that the graduations get hard to read with epoxy on them.  I
    usually hit them with a marker first so that they show up better.  As
    Eric says, the cups are cheap if you buy a hundred pack.
    
    Charlie
    

I couldn't find them cheap so I made my own on demand. It's easier for me 
to trash them after use than to take the time to clean them for reuse due 
to my throughput issues. My per cup cost is about a penny a cup. I'd love 
to get premarked cups in this price range. Where?

    
    Enough already.  8-)

    My last bacth came from Hobby USA I think.  It was the same company
    that makes the 9 oz epoxy.  I can't remember the 3 character name.  It
    was like a hundred for $3 I think.  Reusing them costs more in solvent
    to clean them than the cups cost.
    
    Charlie
     

Tom (Tom's Hobby Korner) makes the epoxy under the NHP name (Northeast 
Hobby Products). I've never seen the cups in his shop though...


(sure, give me the name of a place that closed 8^)

    I usually get my mixing cups from the cafe. Some foolish people
    that don't know any better use them to put ketchup in for their
    fries. 8^)

    Jim,
    	Hobby USA is alive and well in Bellingham.  This is more convenient
    than Ashland for me.  NHP is the distributor that my last cups came
    from.  It was a pack of 100 I think.  I'll check at home.
    
    Charlie
    

Yeah, I know the Ashland store moved and reopened. I just never found that 
store convenient since I rarely head down that way. My buddy in Mansfield 
does so maybe I'll ask him to pick some up for me.

    Nice thing about that store is it's right off of 495.  (and on the way
    to the Loopers field)  Ashland was always a pain to get to for me.
    
    Charlie
    

    
    
     I CAN'T believe after the Roy Rogers escapade after the Wram show 2 years
    ago, that ANYONE is even talking about purchasing cups for mixing
    epoxy! :)

Sorry, I missed that session I guess.

I nee to mix 2oz batches of epoxy so the ketchup containers would be too 
small. When I'm in wing press mode, I need a dozen a night and don't want 
to clean them out. They actually have to be bigger because I mix collodial 
silica in also.

    Jim's in Mass Production.  20 Oz of Envirotex lasts me a year or two so
    the small cups are fine.  I have mixed larger batches in regular
    plastic drink cups after measuring with the small ones.  I flush the
    small ones with alcohol to get all of the epoxy out.  I'll be doing a
    couple of Gremlin wing bottoms this weekend.
    
    Charlie
    

The next gallon set of epoxy I order will probably be West. I can get pumps 
for it for $8. The pumps aren't fool proof but for 2oz batches, they're 
close enough.

I can do a 20oz set in a weekend 8^)

    I just mix whole bottle fulls at a time. Saves think time and heats up
    the workshop in the winter!!!!!!!!!!!!
    
    EVL-1
    

So THAT'S what's in those one use hand warmers!

What is a good way to bond aluminum to aluminum? The joint doesn't have to take
extremely high stress, but some stress. I am looking for ways to
perpendicularly butt join thin (e.g., 0.032") sheet aluminum, in smallish
pieces, of the order of an inch long joint. 

I imagine that epoxies work OK, but epoxy is a pain to mix and is very
wasteful. I experimented with ZAP-A-GAP CA (the only superglue I had), and the
joint wasn't quite as strong as I'd like, though it was pretty good and might
do. I will probably purchase and try a thin CA to compare. Any other ideas?
						-- Tom

That's a tough one.  Aluminum oxidizes so quickly that the time it
takes to apply epoxy is *almost* too long to make a good joint.  The
processes I've seen recommend an acid bath immediately before applying
the glue.  I've never done it, but I'd recommend some of the low temp
brazing methods using a Bernz-o-matic torch.

    Can you fold it over at the joint to get more surface area?  If so,
    then rough it up and use epoxy.  Make sure that the surface is clean. 
    CYA will also work well if you get the surfaces very flat.
    
    Charlie
    

How about using thin CA with a baking soda fillet along the joint to give 
it more strength. 

RE: last few replies

Thanks for the suggestions. I bought some thin CA and tried it two ways,
neither of which was very strong:

1) Apply a drop straight to the joint, and let it sit about three hours (it was
   wet for at least 30 minutes). I used the point of a pin to pull the CA along
   the joint; it didn't spread out very far on its own. The surfaces had been
   sanded immediately before glueing.

2) Apply a drop as above, and then sprinkle a light dusting of baking soda.
   Hardened immediately, let sit three hours anyway.

At the end of three hours, I tried to bend the two test pieces over (which
were butt glued perpendicularly to a base of the same aluminum, K&S sheet).
The piece with straight CA popped off with very little effort. The CA + a
little baking soda popped off with slightly more effort, but still quite a weak
joint. The fillet was pretty ugly too, which would be difficult to clean up on
the real project.

I think welding would be too awkward for my project, because (if I end up
doing this for real) there would be lots of parts in close proximity, and I
would be scared of damaging adjacent joints. As an earler experiment, I tried
using sheet brass and soldering the pieces together. With a propane torch
adjacent joints loosen up and parts fall off; with a soldering iron it wasn't
possible to get the sheet hot enough to get a good joint, because the area of
the sheet acted as a great heat sink.

I'll probably try epoxy next, but I'm leaning toward using a different material
altogether. One that comes to mind is sheet styrene, because it cements very
easily and well with liquid plastic cement (it's also much easier to cut). But
I'm afraid it's not rigid enough in .032 thicknesses. I'm shy of using wood
because of long-term warping, and because of splintering cross-cuts that are
very unsightly and a pain to fill and clean up. (Most sheet wood parts that I
have which are this thin and aren't well supported on all edges end up warping
after five or ten years, even plywood).
						-- Tom

That's not too far off. When I did the landing gear on the Robin, I
used aluminum tubes and fitted tight brass pieces to the ends held in
place with pins to make the components.

    Re: -.1
    
    1000 units at $70 works out to 7 cents per unit, not 70 cents!
    
    -Joe

    Check your local hardware store, probably in the plumbing section.
    Stuff like liquid solder, or liquid steel. There should be a few
    different types of "stuff".
    
    Steve

Here is what you should do.
Go see how experts build there.

I suggest attending Top Gun in Florida.
Call and confirm dates and get a flight and take your wife.

God it's cold outside.  Sure glad I already have my January flight in.

Bye          --+--
Kay R. Fisher  |
---------------O---------------
################################################################################

I apologize for posting this but I thought people would find it humorous.

Jim

WEIRDNUZ.393 (News of the Weird, August 18, 1995)
by Chuck Shepherd

* At a March conference, a University of Pennsylvania
radiologist told colleagues he had successfully sterilized all 17
rabbits in his experiment by squirting a substance similar to Super
Glue into their fallopian tubes and said he would seek FDA
approval to test his procedure on women.  And in May, Pacer
Technologies announced it was seeking FDA and Department of
Agriculture approval for using a variant of its Super Glue to
prevent salmonella contamination by sealing the rectums of
chickens and turkeys.  The product would be known as Rectite.
[New Haven Register-AP, 3-29-95] [Inland Valley Daily Bulletin
(Ontario, Calif.), 5-16-95] 

    Just a data point in the discussion about CA, epoxy and lung problems....
    
    I have convinced myself that after years of breathing CA fumes, my 
    lungs can't take it any more.  I have had to switch to UFO...
    
    Last spring when I got on a building kick, I noticed that I was 
    constantly out of breath.  In the morning, before work,  I would glue
    a few pieces then glue some more in the evening..  Well, at work, 
    even 1 set of stairs got me breathing hard.  About this time, Joe and I
    sheeted some cores and we spent a hour or so inhaling epoxy fumes as
    well.
    
    I went to the doctor and they did an EKG and everything else, but
    they could find nothing wrong.  For a number of reasons, model building
    got put on the back burner..
    
    As some of you know, recently I started working much harder on my
    Nieuport-11.  Things were going fine and I was mainly using epoxy with
    no apparent side effects.  Then one piece just begged to be glued with
    CA.  To form this piece, it was a drop of CA at a time, then hold it
    until it was set.
    
    Well, the next day, I was out of breath again!
    
    I layed off of the model building for a couple more weeks.  Then,
    Monday morning I got up early and used some CA...  Once again, it gave
    my chest this tight feeling..
    
    ---
    
    I now have some fans in the room and I am giving away all of my zap!!
    
    Moral of the story (if you have read this far) is that just because it
    hasn't bothered you before, doesn't mean that you will always be safe 
    from its effects.  Take precautions now so that you will be able to use
    these glues later!
    
    Cheers,
    jeff
    

Jeff, those are some of the best reasons for balsa-slow ever reported .....

;>

-Joe

In following some soaring links this morning, I ran into an article on the
health risks of epoxy on the web. 

http://www.cursci.co.uk/rc-soar/epoxy.htm