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I have an Almansa classical guitar that needs a bit of refinishing work and I'm wondering what the best way to go about determine what the existing finish is. I did a small acetone test and it seems as though the finish withstood it without any issues (didn't come off or become tacky). I'm pretty sure Almansa would not be using any type of polyurethane finish but I'm looking for a way to determine a compatible finish to air brush on. Should I apply a coat of shellac just to be certain or would it be safe to just spray on a bit of lacquer (EM6000)?

Thanks!
Charlton

Have you tried contacting the maker and asking them?

Yeah, I did. No response.

Dang...

I have always heard (and my limited tests seem to verify) that if DNA softens it it is probably shellac, if lacquer thinner softens it it is probably nitrocellulos lacquer. My (limited) experience is that lacquer thinner does not soften catalyzed poly-somethings. I know that when I was shooting waterborn finishes (KTM-9) DNA would make the surface tacky between coats.

EM6000 is not a solvent lacquer - I would not expect it to melt into nitro if that is what is on the guitar.

Other people have far more experience than I do but I have learned that I cannot repair any of the modern finishes and I no longer try. My French polish technique is not good enough that I would want to try to repair a quality guitar with FP - I just can't get the spiriting off stage to my satisfaction. Nitro is no problem.

Two more thoughts. Why are you sure that it is not some modern poly finish? I recently worked on an Alhambra classical guitar and I am quite sure that it was poly. I would expect any modern commercial builder to be using it.

Last point, are you really sure that it refinishing is the right thing to be doing? Most of the time us amateurs make matters worse and if it is a valuable guitar we often reduce the value.

I'm actually not 100% sure that it's not poly but I just didn't think that poly was typically used by manufacturers. This is actually a low value classical guitar so the value isn't really the concern but I do want to try to deal with the finish if I can.

Thanks!
Charlton