Official Luthiers Forum!

Hi all,

I'm working on my first acoustic guitar build, and everything was going swimmingly until this afternoon. I was polishing the finish (KTM-9 waterbased lacquer) with a foam polisher secured in a benchtop drill press at low speed. Unfortunately (and stupidly) I hadn't re-secured the drill press to the workbench after having moved it the night before, and so it fell over onto the guitar in my hands. Much of the damage I was able to sand out, since my finish is reasonably thick, but there are two points of damage that I don't know how to fix.

1) A deep scratch: I'm not 100% sure, but I expect that this goes all the way through to the wood at its deepest. Picture: http://tinypic.com/r/2zqwzmx/5

2) A series of deep grooves: These definitely go down to the wood, but the finish seems to have done its job and the wood doesn't seem to be damaged. Picture: http://tinypic.com/r/10fs0gg/5

So my question is: Do I need to sand back down to the wood and refinish the whole top, or can I fill the scratch/grooves with something and then do a couple of overcoats of finish?

Thanks!

kendorin,
Bummer! The good news is that you now have an opportunity to experiment. For most everyone accidents and mistakes and figuring out how to fix them are all part of the learning curve. There are myriad ways you can go from here. Faced with your situation I would first attempt to drop fill and topcoat the damaged areas. If I found those results unsatisfactory I would then sand back and refinish. If I was still unhappy I would replace the top entirely.

Try searching for words such as "drop fill," "scratch repair," "replace top," etc., and you will likely find some useful threads. I would also recommend browsing Frank Ford's excellent website http://www.frets.com. It is an invaluable resource and offers detailed information on a wide range of guitar maintenance, repair and restoration techniques.

Good luck,

_________________
George :-)