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My first post and my first guitar. I'm having an odd problem.Presently I'm spraying nitrocellulose from a can. My undercoats are dewaxed shellack from a can and a lacquer sand and seal. I've now put on about 4 coats of the nitro. after the first couple of coats I sanded and wiped down the guitar with naphtha.Today I layed down a pretty good coat and upon drying the cross bracing is showing, along with a milky quality to the finish. I believe the the milky quality may be because of the lacquer being too thick, but what is going on with the shadow of the bracing showing through? I was going to add an image but am unsure how to reduce the file. I will add that the top is redwood. Any help on why or how the shadow of the bracing could show through 1/10" of guitar top would be greatly appreciated.       

It sounds like the humidity is too high where you are spraying and you are
experiencing blushing. Mix in a little butyl cellusolve to your next few coats
and spray them a little thinner and lighter than before and it should go
away. Butyl cellusolve is often sold as a lacquer retarder, and it slows the
drying process to allow moisture to escape as the VOC's evaporate.

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Eschew obfuscation, espouse elucidation.

Oh sorry, I just reread your post and saw that you are spraying from a can. If
you're using nitro, the blushing should still bleed through to the surface and
come off with rubbing, buffing or steel wool, but it may take a little while if
the humidity is too high. In the case of canned lacquer where you can't
control the mixture or content, you just have to adjust your spraying pattern
and schedule for the humidity. In dry weather you may be able to spray
coats at 20 minute intervals, while in higher humidity you may have to wait
as long as 2 hours and spray lighter. If the humidity is too high (above
70-75%) it may be best not to spray at all until the weather cooperates.

_________________
Eschew obfuscation, espouse elucidation.

The blushing is probably not seen at the braces because of the extra thickness added by the brace. This would account for the "imprinting". I believe that one of the suppliers sells butyl cellusolve in spray cans as blush ereser.

AlA Peebels38970.7281712963

Back in the Dark Ages when I was lacquering, I found that simply re-coating the blushed surface erased the blush. If you continue to spray with a can, you might want to wait for drier weather. I never used blush eraser, but I would be hesitant to spray a slow evaporating solvent like cellusolve directly on the lacquer film. It seems like it would be many moons before it totally gassed off. Retarders are meant to be added to the liquid lacquer in small quantities to slow down the evaporation of the solvents. If you mess with retarders, which are very toxic, without proper protection, you are likely to become "retarded" yourself.

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Stay with the happy people.
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thanks everyone, i easily sanded it out and recoated with no problems.

By the way, welcome to the forum, David!

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Scott Thompson
Port Townsend,WA

"In a perfect world we'd all sing in tune
But this is reality so give me some room"
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