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Scratch repair
http://www-.luthiersforum.com/forum/viewtopic.php?f=10137&t=51569		 Page 1 of 1
Author:  Mdo [ Wed Feb 06, 2019 5:46 pm ]
Post subject:  Scratch repair
Hi all, I am in need of some advice on repairing some scratches. They go from light to deep. The deepest goest about an inch long where you can just see wood. I have some experience with furniture building an simple staining and poly but that’s as far as it goes for me. Since the guitar is black lacquer my thought was to slowly fill it in with black then clear lacquer then wet sand. I have probably simplified it, I understand that it is complicated and can be ruined if not done correctly. Any advice would would be appreciated. Thanks!
Author:  Barry Daniels [ Wed Feb 06, 2019 6:58 pm ]
Post subject:  Re: Scratch repair
I have been using Glu-Boost recently which is CA glue. They make tints to mix in for the color. The advantage is that it cures quickly. Lacquer would need to dry for a few weeks or it will shrink back.
Author:  Smylight [ Wed Feb 06, 2019 9:14 pm ]
Post subject:  Re: Scratch repair
Barry Daniels wrote:
I have been using Glu-Boost recently which is CA glue. They make tints to mix in for the color. The advantage is that it cures quickly. Lacquer would need to dry for a few weeks or it will shrink back.


+1 for GluBoost. Fill 'n Finish is awesome for this kind of repair.


Pierre
www.torvisse.com
Author:  B. Howard [ Thu Feb 07, 2019 8:35 am ]
Post subject:  Re: Scratch repair
Oh my!!

First, black isn't always black.... some add blue or purple to add luster others use just lamp black so getting the correct black is the first key. I would not use CA for lacquer repairs, will be very difficult to level and buff evenly without going through the surrounding lacquer and even then the difference in light refraction and clarity (nitro yellows, CA doesn't)will make these jump right out.

With the size and amount of scratches I would sand this back some at 400, make minor touch ups on bare wood only with the right black lacquer and then re-clear the back. Or you can call it "Reliced"....
Author:  Barry Daniels [ Thu Feb 07, 2019 9:06 am ]
Post subject:  Re: Scratch repair
Brian, I agree that repairing it with lacquer would be best assuming that the original finish is lacquer and assuming that the OP is setup for spraying lacquer. If neither is correct then a CA repair may be the only feasible option. Plus the time frame of the repair is certainly a consideration (ie.; one day versus one month). A CA repair will never look as good as a lacquer repair, but it would definitely be an improvement on the existing look.

Regarding leveling the CA if that is used for the repair, Frank Ford's razor blade with a turned hook is just the ticket.
Author:  Mdo [ Thu Feb 07, 2019 10:56 am ]
Post subject:  Re: Scratch repair
Thank you all for the input. I was hoping to use a small brush to fill in the scratches with black lacquer then clear and wet sand. I am not set up to use a spray gun at the moment.
Would you guys suggest first sanding back the raised edges of the scratches first?

Jaime
Author:  Barry Daniels [ Thu Feb 07, 2019 11:12 am ]
Post subject:  Re: Scratch repair
You should only sand back the edges if you were going to spray it, so in your case, no.

First thing to do would be to verify that your existing finish is lacquer. Place a drop of lacquer thinner someplace where it won't show like under a pick guard or truss rod cover. Let it sit for a few moments then wipe it off with a cloth or paper towel. If it is lacquer you will see a small, shallow crater. If no crater then you may have a poly finish.
Author:  Smylight [ Thu Feb 07, 2019 11:18 am ]
Post subject:  Re: Scratch repair
Hey guys, I know I’m sounding like a living ad for this product, but have a look at these videos before you make up your mind, and don't miss the one by Mario Beauregard. I've used the Fill'n finish with the black colored powder myself and can attest to the quality of the finished touch-ups. It blends easily with the original finish. Much less involved than a refinish and probably sufficient for the OP's needs, as long as you follow the (simple) process.

https://gluboost.com/videos/


Pierre
www.torvisse.com
Author:  B. Howard [ Thu Feb 07, 2019 3:50 pm ]
Post subject:  Re: Scratch repair
Smylight wrote:
Hey guys, I know I’m sounding like a living ad for this product, but have a look at these videos before you make up your mind, and don't miss the one by Mario Beauregard. I've used the Fill'n finish with the black colored powder myself and can attest to the quality of the finished touch-ups. It blends easily with the original finish. Much less involved than a refinish and probably sufficient for the OP's needs, as long as you follow the (simple) process.

https://gluboost.com/videos/


Pierre
http://www.torvisse.com



Yes, a youtube video beats all my hands on experience here..... laughing6-hehe
Author:  Smylight [ Thu Feb 07, 2019 6:42 pm ]
Post subject:  Scratch repair
B. Howard wrote:
Smylight wrote:
Hey guys, I know I’m sounding like a living ad for this product, but have a look at these videos before you make up your mind, and don't miss the one by Mario Beauregard. I've used the Fill'n finish with the black colored powder myself and can attest to the quality of the finished touch-ups. It blends easily with the original finish. Much less involved than a refinish and probably sufficient for the OP's needs, as long as you follow the (simple) process.

https://gluboost.com/videos/


Pierre
http://www.torvisse.com



Yes, a youtube video beats all my hands on experience here..... laughing6-hehe



I can get the not-so-tongue-in-cheek humour, Brian, and I have the greatest respect for your work. But have you tried this product yourself? If the answer is "yes", I'll respectfully bow out, cease and desist. As a mere guitar tech, I'm certainly no finishing expert myself, but I have successfully repaired scratches, dents and even bruised, flaked scars with this. You should give it a try if you have not already.

I'm sure you will agree that Beauregard's use of the product says something about the seriousness of the method.

I don't mean any disrespect, just trying to help the OP, who has no finishing facilities from what I understand. I posted the links to the videos from GluBoost so he can get info on the product, and the process before deciding what he'll do.

That might include sending his guitar to you for a real pro job.




Pierre
http://www.torvisse.com
Author:  Chris Pile [ Thu Feb 07, 2019 6:45 pm ]
Post subject:  Re: Scratch repair
Does anyone still use burn-in lacquer sticks? Seems like that would be perfect for this repair.
Author:  Barry Daniels [ Sun Feb 10, 2019 11:48 am ]
Post subject:  Re: Scratch repair
Here is a current repair where I used Glu-Boost and it turned out great. I had to surface the neck a little which extended the flat area about a 1/4" past the edge of the nut. I hit the exposed maple with a black sharpie and then built up some clear Glu-Boost. The repaired area is a strip about 1/8" wide directly behind the nut. It blended into the black lacquer very well and it was super easy to level and buff. I did the buffing by hand with a little compound on a rag.
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