Repairing Scratches in French Polished Top

[Danny Seamon]

I'm sure that this has been covered before but I can't find it searching for "repairing french polish". I've done 4 guitars, all french polished and, for the life of me, can't seem to get one finished without putting some scratches in the top. I read in a lot of places that french polish is easy to repair, but I can't seem to find anything specifically on how to do it.

I'm assuming that one would sand the scratches out? Using what sandpaper and grit schedule? Then start over with the bodying steps of shellac?

Anyway, anything specific would be helpful.
Thanks,
Danny

[Steve Senseney]

If you have an already finished (completed in the past) guitar, and scratch the shellac finish, you can get out your solution of shellac, your pad, and pumice and work over the surface. Do a just a few session each day, and the pumice will quickly build and fill the scratch. Eventually you will have the surface even and the repair should be invisible.

If you have damage to the wood underneath, you need to steam this to raise the wood and even out the surface. Let it dry a day or two, and then you can repair the shellac as mentioned above.

If you are having trouble during the finishing process on a new French polish build, that is another problem. I usually suggest letting it dry well in between sessions, and less sessions per day. If you are working it too much, the shellac can build up and be too soft, and it will peel off of the surface like a thin layer of jello. It needs to dry longer and then it will stick to the lower layers.

If you have too much pumice on the surface, use 300- or finer grit sand paper to lightly sand off the pumice, then return to your normal build up process.

I hope this helps.

[Danny Seamon]

Steve, This is on already finished guitars. No problem with initial finish that I know of. I followed the Milburn method. Scratches are only in the finish..not through to the wood. I have had trouble getting the pumice to wet out in the past...even using only alcohol. The only thing I can think that I was doing was using too much at one time on the pad? It never shows up on the surface, just as occasional white specs in the pores..particularily on this last one which is walnut. Of course I've never used it on a top. Thanks for the help. Danny

[Steve Senseney]

So, are you talking about a little pumice in the pores, or some pumice in the surface finish, or the finish is fine, you just have a few swirls in the finish on the surface?

My instinct is to use a dilute solution of the shellac on the surface. Don't use a very wet pad.

Build up a little more on the surface, let it dry well (several days) , and then polish it down with micromesh or something similar.

[Waddy Thomson]

Small amounts of pumice go a long way. I use, either a pounce (pumice wrapped up in a piece of t-shirt material, which you can bop on your muneca to deposit pumice in small amounts) or a salt shaker which also deposits a bit more at a time, but not too much. Clear it with alcohol, then add one drop of diluted shellac, then wipe a tiny bit of olive oil on the pad (less than a full drop). Don't work the damaged area in a concentrated way. That will get you in trouble every time. Work all around it with the scratches in the periphery of your working area. You'll find that it fills the scratches slowly, but they do fill, and they don't show. I've repaired so many nail scratches that way, I hate to think about it.

[Danny Seamon]

Waddy, Thanks.
I'm trying to learn about two issues actually. 1)Issue one is the scratches on the top after the guitar is finished. I think I understand your method but see the question below.
2) My second issue is white specks of pumice in this guitar back (walnut).
Do I understand that you actually bop the pounce bag against your muneca instead of on the guitar? That's interesting. I can see where that would deposit much less than what I'ved been doing. I've been using a salt shaker but shaking out the pumice onto a white typing paper. I would then put alcohol on the muneca then touching the muneca to the pumice on the paper, then another drop or two of alcohol and clear it. It appeared to be clear on the pad but on the back of the guitar (walnut) there were some visible white specks.

Actually I thought of another question. How do you handle getting close to the bridge and pickguard while repairing the scratches on the top?

Thanks again to all for all the help.
Danny

[Waddy Thomson]

Art gum erasers make a good tool for getting into the corners. I cut off a piece and wrap it in a couple of layers of cotton muslin. Use it like a regular muneca. The corner and the sharper edges get right up to corners like bridge, fingerboard and heel.

[Rick Rosenberg]

One could try a Finisher as I have seen Mario Beauregard use these products to fill the pores and buff to a high gloss. I've also seen Ian Davlin do repairs this way as well. Not sure about this exact application however I think it would work just as well.

[David King]

Rick, If you don't have a clue as to how these fine gentlemen apply your fine products to their fine guitars perhaps you might ask them and find out for us or better yet tell them to drop in and tell us for themselves.