Conference vmszoo::rc

    What is the engine made of, what kind of thinner did you use, and
    what kind of container did you use for soaking?
    
    Willie

    Marc,
    
    I had the same thing happen to the aluminum parts of a spray gun.
    I'd gotten into the habit of disassembling the spray nozzel and
    placing the parts into the gun's cup along with enough thinner to
    cover the parts.
    
    Like your experience, some time elapsed before I had occasion to
    revisit the gun and, when I looked into the cup, I found a terrific
    mess; all the aluminum parts had corroded badly and steel parts
    had rusted.  It was a write-off...I had to order all new parts and
    rebuild the gun.  Needless to say, I no longer soak thing in _any_
    solvent for extended lengths of time unattended.
    
    Depending on the severity of the corrosion, you may well have washed
    out the engine (no pun intended).  It'll probably take a wire brush
    and hours of careful cleaning to get things to where you can assess 
    the extent of the damage.  Sorry 'bout that, amigo.  

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

That doesn't sound good....  what kind of thinner was it?? I've *never* had
a problem soaking my spray gun in enamel reducer or lacquer thinner. However,
I wouldn't recommend soaking a spray gun head, or anything else possessing 
nonmetallic substances in lacquer thinner for extended periods of time.  That
stuff is *potent*, and can do a number on seals, gaskets, etc.

Was the thinner Thin-x or a similar "hardware store" thinner??  That has all 
kinds of "other" ingredients and detergents... *don't* use it....

/Brian

    Brian,
    
    In the case of the spray gun, I was using plain ol' Aero-gloss thinner
    and was soaking only the nozzle parts, i.e the nozzle itself,
    needle(s), etc.  Nonetheless, the corrosion, pitting, etc of these
    parts was incredible...I'd never have believed it if I hadn't seen
    it myself; they turned a nasty gray color and looked like the surface
    of the moon from all the pitting.  If anything even approaching
    this happened to Marc's engine, I'm afraid all he's got now is some
    expensive scrap.    

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

    Yup it was thin-x type (I got from the local H/W store).
    
    The body is aluminium. some other parts steel..
    
    the contained was plastic..
    
    Now anyone got a clue what that gummy stuff is ???
    
    md

    
    PLASTIC
    
    Zz

    ok, so how can I get off ?? (heating it comes to mind)..
    
    will Gasoline disolve it ?
    
    ideas welcome ..
    
    m

    Acetone, perhaps??  It'll attack/dissolve many/most plastics.    

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

    Lacquer thinner would get my vote, use a *glass or metal*
    container ( just to re-state the obvious).... Acetone would 
    probably work just as well..... 
    
    Allright, my final vote is acetone or lacquer thinner depending
    on; a) whatever's cheaper or b) whatever you already have
    on hand... Both should dissolve plastic equally as well. I would
    change solvent every few hours and use a toothbrush to clean
    and to try remove loosened up crud between baths'....
    
    DougT

    right.. I will get on it .. I have neither acetone or lacquer thinner
    on hand.. I do have a tooth brush..
    
    I guess I now get to learn out to strip one of these babies down..
    I use to be able to dismantle COX .049s blindfolded. A .40 is somewhat
    more intimidating..
    
    tx for the help so far.. I will keep you posted..Do keep them cards
    & letters coming..
    
    
    md
    

    Umm, I suspect that electrolysis may have caused a large part of
    your problem, any 2 different metals in an electrolyte will make
    a battery, current will flow, electroplating will happen (material
    will be removed from one metal (pitting) and deposited on another
    (discoloration)).  A metal container will worsen the effect, use
    glass.....
    
    Willie

...while we're here...how do you remove that yellowish-brown
stain that collects on the upper cylinder head? It seems to come
from raw fuel (from the exhaust?) burning on the hot head.  That
stuff is nasty to get off; I haven't found a way to do it yet.
 

    I don't think I've got a pitting problem. The engine is all covered
    with this gummy crud..
    
    md

I can't give a definitive solvent suggestion, but I would recommend getting your
hands on an ultrasonic cleaner. I used one to clean the crud off of an old .049
that had just been tossed into the toolbox with all of the fuel, etc. still
in/on it ... 30 years ago. It was impossible to disassemble any part of it until
I treated it in some fuel in a glass beaker which in turn sat in about an inch
of water in an ultrasonic cleaner. I don't know if that would work to remove the
(plastic?) crud you've described. 

One safety point to observe is to always work in a well ventilated area whenever
you put organic solvents in an ultrasonic cleaner. The vibrations have the
ability to break down those solvents into some pretty toxic substances, such as
phosgene, etc. 

Dave

>   ...while we're here...how do you remove that yellowish-brown
>   stain that collects on the upper cylinder head? 

    Ever since I converted to Red Max 12% with all-synthetic oil my engines
    have continued looking like new. The stuff that bakes onto your engine,
    forming a hard, ugly shellac-like coating is castor oil.  I
    think some oven cleaner might work but be very careful that it
    doesn't attack the aluminum.  I remember Charlie Watt tried some
    oven cleaner with good results (Charlie was a die-hard castor-oil
    man until seeing the good results we were having with synthetic
    oil).  My OS 25 FP has been running with this fuel for three years
    and starts and runs today like it did when it was brand new.
    
    Bill

    I've had varying degrees of success using automotive carburetor
    boil-out, Easy-Off oven cleaner and some stuff, I believe intended
    for cleaning the sole-plates of electric irons, called [I think}
    Metal-Kleen, available in the cleaners section of most super-markets.
    
    Naturally, all these are caustic substances and all necessary safety
    precautions should be taken when using them and prolonged exposure
    of metal [or human] parts should be avoided.
    
    Like Bill, I ceased having the baked-on gunk problem that makes
    yer' engine look like a "pot-roast special" when I went to
    synthetic-lube fuels.  Of late, however, I've run a gallon or two
    of 10% Omega fuel which uses a castor/synthetic blend and, sure
    enough, the baked-on varnish is returning so I need to clean the
    cylinder heads of my engines and return to the synthetic lubes.
    I find little hazard to this provided you have enough experience
    and/or exercize adequate caution to avoid over-tweaking the needle,
    resulting in a _really_ lean run. 
    
    FWIW, I've had extremely poor luck trying to use a toothbrush with
    acetone and/or lacquer thinner.  Why?  Think about it; the acetone/
    thinner attacks the plastic in the toothbrush and, before ya' know
    it, whatever yer' workin' on is covered with disconnected little
    bristles and the brush-end of the toothbrush looks like it's developed
    a case of _mange_!  I found some small, fine-wire brushes, just
    a little larger than a toothbrush that work great for these kinda'
    chores.  Check yer' local Standard-Brands or other volume/discount
    paint/arts-crafts stores for these handy brushes.

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

    re acetone & toothbrush:  good point..I will look for fine wire
    brush.
    
    
    re ultrasonic cleaner: How do this beasties get the job done: Just
    rock & roll the part in the cleasner solution til evering is loose??
    
    
    RX,
    
    MD
    

    Pretty much, though ultrasonics actually cause cavitation in the
    liquid, and it's the tiny little shock waves caused by the bubbles
    collapsing that actually cleans the part.  Works really well.
    
    Willie

    In response to de-gunking an engine, I hear that soaking the 
    assembled engine in kerosene for a few day works well.  I haven't
    tried it but because this comes from a friend who has been in the
    hobby for over thirty years, I tend to believe it works.  
    
    Norm

    The stuff I used to degunk my engines that had baked on castor was
    Sunbeam Aluminum cleaner designed for degunking electric frying
    pans.  I got this idea from RCM.  It worked very well, but I completely
    disassembled the engine and only subjected the exterior aluminum
    parts to the cleaner.  I followed the directions on the can and
    did two applications on the thick parts on the head.  It WORKS.
    
    CHarlie
    

                        <Just some water>
    
    On one of my .40 engines had some gumming, try dismantling the engine
    and place the components into a pot of water and bring to a boil for 15 -
    20 minutes. I added a cap full or so of vinager, worked like a charm
    although it will not do much for the baked on castor ..
    
      Tom

    I have been using Karosene for three years now with no problem.
    In fact I store my engines in Karosene if I'm not going to use them
    for awhile. I've never experienced rust or stains since I started
    this. I also spray my engines externally with carb cleaner after
    normal use. Keeps the head clean and any fuel from burning into
    and staining the exterior of the engine.
    
    If you haven't done anything yet you might want to soak it in Karosene
    for a week or so and hit it with a stiff small brush. I onetime
    tried to clean a head with my wife's aluminum cleaner. Looked beautiful
    but put pits on the underside. Ruined it.
    
    Bob

    John Tavares raised the question of removing baked-on castor oil
    in reply .12 and has had a number of replies.
    
    Over here in the UK we have a range of new products for model engine 
    care one of which seems to work well for removing this muck.
    
    I have not used it myself as I have not been flying long enough
    to get any oil baked on my engines ( I also clean down after each
    flight with a proprietary model cleaner ) but I quote from the June
    '88 issue of Radio Control Model World.
    
    ENGINE BAY by Peter Miller .......
    
    "M.D. Products Clean UP
    
    M.D. Products have been kind enough to send me a set of examples
    of their products. Formula 1 which coats the inside of an engine
    with P.T.F.E. and which I started to test some time ago but, for
    various reasons, could not complete the test, now I can carry out
    tests on several engines and report my findings.
    
    Formula 2 which is an after run oil, as this would be a long term
    test for corrosion protection I plan to carry out a special test.
    
    Formula 3 is an engine cleaning gel which is claimed to remove even
    burnt on oil. As I have heard that one before I was eager to try
    it out.
    
    The blackest most burnt item I could find was the silencer from
    my Laser 61 so I coated part of this with the gel and left it for
    the required four hours and then brushed it off with water and guess
    what ... ir really works, the parts that had been treated came up
    like new while the rest stayed as black as ever, even after going
    over them with a wire brush.
    
    The gel is not caustic or acid but care must be taken when using
    it. It does not damage aluminium. Now there is no excuse for an
    engine that looks like a lump of coal in the front of your model.
    
    M.D. Products are available from all good model shops ( _he is
    obviously refering to the UK here_ ) or you can contact M.D. Products
    at 244a, Colindeep Lane, London, NW9 6DE."
    
    ..... end of quote
    
    I checked with directory enquiries for a phone number so that I
    could ask for the name of a US distributor but there is no listing!
    
    If anyone over the other side of the pond there would like to try
    it let me know and I will try to track down a distributor or get
    some sent over.
         
    
          |
    -------------
         ( )         <-------- how's this for a logo?
    -------------                  it's supposed to be a Flair Legionnaire!
        /   \
                                                                           
    Brian Warwick
    

    Ref: 663.23
    
    don't try to VAXmail me at ODIHAM - this is an ALL-IN-1 only cluster,
    or so the system manager tells me and he won't let me have a VMS
    account
    
    my RCS is BST so mail me ( DECmail or ALL-IN-1 or VAXmail via the
    message router to ALL-IN-1 ) as Brian Warwick @BST
    
    if you want to call me my DTN is 768 5239
    
    Byeeeeeeeee
    
     

    Brian, 
    
    I, for one, would be interested in learning whether this
    stuff can be obtained from a US distributor.    

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

        Back when it was possible to work on a car yourself, I used a
        product called GUNK to clean carbs and other parts. I'll bet this
        would do fine to clean up your engine, providing you only soak the
        metal parts. It was available in big cans, with a 2 layer liquid.
        The stuff on the bottom was the cleaner/solvent, and the top layer
        kept the rest from evaporating. I think small cans and sprays are
        also available.
        
        Disclaimer: I've never tried this on an RC engine; my model rocket
        engines don't need cleaning. 

Regarding gummed engines, I have a question for you engine wizards...

I have a OS .40 that has sat out 2 seasons. When I looked at it last night, I 
noticed it was a little on the gamy side (OK, allot on the gamy side). I 
took no special precautions when I packed it away, so I believe there should be 
a little old fuel, dust, grime and  other unmentionables. My question is, what 
should I do before putting the engine back into service??

Thanks
	Bob

    Well, I have reported earlier that my OS SF 46 ABC gets fussy when it
    is all gummed up on the exterior, and the day is hot, causing stresses
    due to inadequate/uneven cooling.
    
    The much touted Sunbeam Aluminum cleaner is no longer being made, and I
    was contemplating on buying what is advertised in Model Aviation for
    $6.95, when I questioned Harvey Thomasian, the local engine expert and
    chemist.
    
    He said that all the cleaners contained a caustic substance (lye), and
    in differing concentrations, and gave me courage to try the regular
    oven cleaner.
    
    I decided to use Mr. Muscle oven cleaner spray on the bottom of my
    muffler, where, any mishaps would remain concealed from view. I let the
    spray sit for 5 minutes, and attacked with a toothbrush. That was a
    little too long, I found, as the lye darkened a small part of the
    muffler that didn't have a brown deposit on it.
    
    Sooo, encouraged, I sprayed the top of the muffler, and rinsed off with
    hot water at the kitchen faucet in about 15 seconds. Amazingly clean!
    That brown tarnish disappeared!
    
    Then, bolted muffler to engine, took out carb, plugged intake, and
    sprayed cooling fins. Worked with brush for a minute, and got _most_ of
    it out. I gave it a second shot for the final job. 
    
    During this second attempt, I got some overspray onto already clean
    metal, and that left a few, _barely_ visible marks, but the engine
    looks like new, and no one notices the marks unless I point it out to
    them.
    
    Seems like if you take care to prevent overspray (with a plastic
    bag/tape, etc..), this works great!
    
    Try it, you'll like it.
    
    ajai