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Conference noted::woodworking_and_tools

Title:Woodworking and Tools
Notice:INDEX see 5.nn, BUY/SELL/SWAP see 7.nn
Moderator:BAMVAX::GOODWIN
Created:Sat Mar 01 1986
Last Modified:Wed Jun 04 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2113
Total number of notes:20008

2110.0. "Questions about Tung Oil Finish" by MROA::PVINCENT () Wed Apr 09 1997 12:57

    I have a couple of questions about a tung oil finish.
    
    The directions say to sand with 400 grit between coats.  Is this really 
    required?  The wood is maple and I used a cabinet scraper so it was 
    very smooth before I started the finishing process.
    
    The directions also state to wait 72 hours before "rubbing out" the
    finish, then wait 7 days before you apply wax.  I'm confused about what 
    they mean by "rubbing out"?  Don't you use wax for this step??
    
    Any help is most appreciated.
    
    Pete
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2110.1DELNI::OTAWed Apr 09 1997 13:0220
    Pete
    
    What kind of tung oil finish did you use.  If it was straight tung oil
    then rubbing out will be necessary. 
    
    I generally look at the first coat to see if any grain raised when I
    apply tung oil  If the grain raised I use 00000 steel wool to sand it
    down.  Other than that I actually use the same steel wool (clean piece)
    to apply further coats.
    
    After a couple of coats and I feel the finish is complete, I generally
    don't add wax.  I have though done that on a couple of pieces, using
    Bri-wax.  I am not sure what the manufacturer meant by rubbing out.  I
    generally buff the tung finish with steel wool to be sure that there
    are no tacky spots left, I have never waited 72 hours to apply wax
    either usually 2 days max.  So I am not sure why your finish requires
    so much time.
    
    
    Brian
2110.2Straight Tung Oil it is...MROA::PVINCENTWed Apr 09 1997 19:3112
    Brian,
    
      Thanks for the info.  I forgot the brand I used, but it is "straight"
    tung oil.  So when you say "rubbing out will be necessary", what does 
    that mean?  Is there some technique I'm supposed to do after the final
    coat?  Or does using steel wool to apply additional coats take care of
    that?  
    
      I never used anything other than polyurethane before, so I'm a little
    nervous about how this tung oil stuff is going to work. 
    
    Pete
2110.3finishing touches....PCBUOA::TARDIFFDave TardiffWed Apr 09 1997 20:3328
	I think traditional references to 'rubbing out' refer
to the final smoothing/polishing done on....traditional finishes.
You start with smooth wood surfaces, and apply layers of 'stuff',
of whatever type you prefer.  Each layer will probably collect a little
dust, hair, have varying thicknesses...which is why you smooth each
one a bit with steel wool before applying the next one.  The supposed
goal is a perfectly flat finish surface, to the touch and the eye (for
reflections).

	Of course, steel wool is always pretty coarse, on an absolute
scale.  To get the final perfect surfaces, you use pumice or rottenstone
(or in sequence) mixed with oil, applied with a block, to 'rub out' and
polish the surface.  Each successive step removes any projections and
replaces big (relatively) scratches with smaller ones.  Get the scratches
small enough and you get a smooth, reflective surface.

	For instance - I often use wet-dry sandpaper, glued to a flat
surface (marble tile) to sharpen tool edges.  Starting with 80 grit,
I get an obvious scratch/gouge pattern on the steel - when that is uniform,
I know it's flat to that level (80 grit scratches).  Each successive grade
(100, 120, etc.) results in a finer scratch pattern, and each step should
remove any trace of larger scratches remaining.  If I take this all the
way down to 2000 grit (11 steps with the grits I've got) I can get a true
mirror finish on tool steel - no naked-eye visible scratches at all.

	Another example - what's the visible difference between a
spray-can-painted auto repair and a professional hotrod showroom finish?
Multiple thin coats and rubbing out....
2110.4Random jottings...WOTVAX::HILLNIt's OK, it'll be dark by nightfallThu Apr 10 1997 11:2217
    From what has been described, in some parts of the English speaking
    world, rubbing out will be referred to as rubbing down.
    
    For the first one or coats it will remove grain fibres that have been
    lifted and project above the mean surface.  On later coats use finer
    and finer abrasives to get a better and better finish.
    
    Car sprayers also use many coats of paint which progressively have less
    paint and more thinners to give a finish with great 'depth' and high
    gloss.  They rub out/down between each coat.  When last I heard, Rolls
    Royce used 27 coats of the final colour, with the last coat have over
    90% thinners in it.
    
    Some years ago, I got a great gloss, depth of finish and durability
    with 7 coats of polyurethane varnish on a dining table.
    
    Nick
2110.5DELNI::OTAFri Apr 11 1997 17:0015
    My error in my description I left of the last steps.  First coats 1-4
    are put on with steel wool.  A XXXXX brand is like 220 grit or better.
    I then after coat 5 drys use a felt pad and rub in pumice with parafin
    oil.  After that is done and painstakingly remove all the pumice.  I
    then rub in rottenstone and then wipe that off.
    
    I once tried using pure tung oil and found it took too long to set up
    and had sticky or tacky spots.  I moved to polymzed tung oil (varnish
    resins are added) and found much much better results.
    
    Hand rubbing the finish with pumice then rottenstone is a very long and
    laborious not to mention boring process, but once you remove the
    rottenstone you get a deep luster thats baby bottom smooth.
    
    Brian
2110.6Cleaing off the pumice/rottenstone?MROA::PVINCENTFri Apr 11 1997 18:136
    Thanks to all for the help....and one last question.  I bought
    pumice/rottenstone to use for the "final" steps.  What is the best was
    to "painstakingly remove all the pumice"?
    
    Pete
    
2110.7DELNI::OTAMon Apr 14 1997 15:3012
    Pete
    
    First thing is to have lots and lots of paper towels.  I use clean
    rubbing oil and clean towels, wipe the entire bench down.  Then again
    clean oil and more paper towels and then more clean oil and more paper
    towells, you get the picture.  It takes a bit of time to remove the
    grit, but you can feel it easily enough to know if there is any left.
    
    The last thing I like to do is add a layer of lemon oil.  It imparts to
    me a nice luster and it smells nice too.
    
    Brian
2110.8Tung vs Danish OilGROOVE::DADDIECOThat's Just The Way It Is .....Fri Apr 25 1997 12:506
    Anyone out there have experience with both Tung Oil and Danish Oil? 
    Being very new to woodworking I'm trying to understand the differences
    between the two products. I would appreciate reading any comments and
    comparisons you all care to offer!
    
    Thanx .... d.
2110.9NEWVAX::LAURENTHal Laurent @ COPFri Apr 25 1997 13:2919
re: .8

>    Anyone out there have experience with both Tung Oil and Danish Oil? 
>    Being very new to woodworking I'm trying to understand the differences
>    between the two products. I would appreciate reading any comments and
>    comparisons you all care to offer!
    
"Danish Oil" doesn't really have a canonical meaning.  Products labelled
"Danish Oil" are really an oil/varnish blend.  I don't remember if the oil
component is tung oil or linseed oil or either.

Many finishes labelled "tung oil finish" are also usually really oil/varnish 
blends.  It's possible to buy straight tung oil, but it's considerably more 
expensive than the blends.

I highly recommend getting a copy of Bob Flexner's "Understanding Wood
Finishing".   It does a pretty good job of explaining these things.

-Hal Laurent
2110.10exDELNI::OTAMon Apr 28 1997 11:5414
    I have tried both. I found pure tung oil takes a long time to dry and
    can pool up and get tacky in the grain differences in wood.  I switched
    to polymzed oils like Watco.  These add varnish resins that make the
    oil dry quicker.  
    
    In my living room I have a sofa table with Watco and a coffee table
    with Tung oil.  You can't tell the difference in finish.
    
    I highly recommend tung oil as a finish because you see the wood and
    can feel the texture over any other type of finish.  One trouble is it,
    is not as durable as say polyurethene and needs to be reapplied every
    now and then, but the finish to me is worth the extra work.
    
    Brian