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cracked finish

Posted: Thu Jun 12, 2014 4:14 pm
by Mike Sandor
I have a guitar that has been finished approx. two years. I have recently noticed that when looking at a angle, there are numerous cracks.
Is it possible to lightly sand the entire surface and respray a very thin mix in effort to melt into the previous finish? Or should I just sand the entire guitar and refinish.

Re: cracked finish

Posted: Thu Jun 12, 2014 10:15 pm
by Steve Senseney
My guess is that the guitar got cold, and the finish cracked as it shrank more than the wood underneath.

It would be important to know what finish was used.

I

Re: cracked finish

Posted: Fri Jun 13, 2014 6:28 am
by Mike Sandor
Steve, that is what happened, the finish is lacquer.

Re: cracked finish

Posted: Fri Jun 13, 2014 8:56 am
by Barry Daniels
What kind and brand of lacquer?

Re: cracked finish

Posted: Fri Jun 13, 2014 9:54 am
by Mike Sandor
Seagrave Nitrocellulose Spraying Lacquer from Stew Mac.

Re: cracked finish

Posted: Fri Jun 13, 2014 10:33 am
by Barry Daniels
In order to re-amalgamate the finish cracks, you will need something more than a thin coat of lacquer. Some folks use butylcellosolve. I have used straight lacquer thinner but it may take several passes to completely remelt the finish. And you need to do this on horizontal surfaces only because when remelted, the finish can sag.

Re: cracked finish

Posted: Fri Jun 13, 2014 11:52 am
by Mike Sandor
Barry,
I appreciate the help. Do you think I need to scuff the surface before spraying?

Re: cracked finish

Posted: Fri Jun 13, 2014 1:49 pm
by Barry Daniels
No, that won't help.

Re: cracked finish

Posted: Fri Jun 13, 2014 1:53 pm
by Barry Daniels
Spray a few light coats of lacquer thinner and wait a couple of minutes observing the surface closely. You will see some healing of the cracks but probably not all the way to the wood unless your finish is really thin. Spray another coat and then observe for a couple of minutes. Repeat until the cracks disappear. The goal is to get the cracks healed with the minimum amount of thinner possible. Let the surface cure for an hour minimum, then turn the guitar and do another surface. Hopefully, the sides don't need this cause they will be a big challenge to prevent sags.

Re: cracked finish

Posted: Fri Jun 13, 2014 2:29 pm
by Mike Sandor
Great, thanks again for the help. The sides look fine, will let you know how it turns out.

Re: cracked finish

Posted: Fri Jun 13, 2014 6:19 pm
by Mark Swanson
Those are just some little old finish cracks. It happens on lots of vintage instruments, and isn't really a big deal. You can of course do as you want, but to me they don't look bad and if it were mine I'd just leave it alone. All old Gibsons are covered with these cracks.

Re: cracked finish

Posted: Sat Jul 05, 2014 1:27 pm
by Mark Wybierala
People pay good money for age related cracks.

Re: cracked finish

Posted: Sun Jul 06, 2014 1:16 am
by Michael Lewis
I think your finish is probably too thick. A thinner film is less prone to check like that.