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 Post subject: Nitro repair - acetone?
PostPosted: Sun Jan 29, 2012 8:12 am 
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I have a dread here that the finish cracked on around the fretboard extension. When hammering frets in this area, the area wasn't supported well enough and the shock caused some cracking and a small piece to flake off. (I was using a block of wood at the time to back these up and had a problem twice. Finally learned my lesson and moved to a better method.)

Anyway, I hung this one up by my chair in the living room and have been playing it myself, but have determined to repair and sell it if I can pull the repair off OK.

So, I won't be able to just burn in new lacquer without removing or first softening the finish down to the wood, as I see it. I know Frank Ford used Cellosolve in some of these repairs. Will acetone soften the finish crack enough to burn back into itself, then allow me to touch up with new lacquer?

I do question whether the bond of the surrounding finish is compromised, since the damage was due to shock. In that case, Frank's Cellosolve method seems to be the ticket, for sure, to soften the finish all the way down and adhere it again. Still wondering if acetone will do the trick, since I already have that one hand. Sure, I can strip the area and redo it, but I figure it's an opportunity to work on my finish repair skills without pulling the neck. Worse thing that happens is I have to pull the neck and strip the area.

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PostPosted: Sun Jan 29, 2012 8:48 am 
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Hi Wes,

Whenever I have to drop fill nitro or do touchup to a small ding or finish crack I first put a drop of acetone on the spot to be repaired. In the case of a crack I will apply it with a very small artist paint brush just along the crack. It will evaporate in a few seconds and then I carry on with the drop fill. This does help the new finish blend with the old, and provided that there is proper dry time you can get an invisible (or near invisible) repair.

Josh

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PostPosted: Sun Jan 29, 2012 3:56 pm 
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You can substitute butyl-acetate for cellosolve. If the finish is fairly fresh a coat of the slowest thinner you have will often be enough to re-flow minor defects.

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PostPosted: Sun Jan 29, 2012 10:27 pm 
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Lacquer retarder is what I use. In my experience, acetone requires many applications to fully soften the lacquer because it evaporates so quickly.

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PostPosted: Sun Jan 29, 2012 10:38 pm 
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I've had fairly good success using the method Josh discribed, only I used lacquer thinner instead of acetone.

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PostPosted: Mon Jan 30, 2012 6:57 am 
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OK, thanks. I was hoping to use what I had on hand. So it sounds like some have had success with acetone, even if it does take several applications.

To be clear, this is one of my builds and the lacquer is less than a year old. There was no other damage done, and the cracking was minor, it was just one tiny piece next to the fretboard that liberated. My only fear was that the bond have have been compromised on the remaining finish, too, but it appears to be stable. It really is minor, just one little finish crack and a tiny piece gone, but I couldn't sell it like that, of course. It's on the south side of the fretboard and not glaringly in the line of sight of the player, but I want to make it right.

I guess I could just open the crack on up and drop fill, rather than trying to penetrate the depth of the finish with acetone, but I wanted to try to repair it. Of course, I do have lacquer thinner, too, and may try it.

Thanks, guys!

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PostPosted: Mon Jan 30, 2012 7:39 pm 
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Brazilian Rosewood
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Todd Stock wrote:
Cellosolve = butyl Cellosolve = butyl Cellosolve acetate...

Cellosolve is more a brand name, a trade mark of Union Carbide that applies to glycol ethers in general. Butyl-acetate is a chemical compound, also known as butyl ethanoate.

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