Removeing lacquer over spray

[carleshicks]

I just bought a 1922 truss rodded F-4 today. It has one repaired top crack that was repaired by Gibson years ago. The top has been over sprayed with lacquer and although it doesn't look bad I was wondering if it is possible to remove it without getting into the color. Or should I just leave it alone.

[Mando Medic]

I've had to do that on a number of instruments and what I have done is to use a slightly abrasive compound, such as Maguires #5 or 7 and literally rub through the overspray. If you use a good light like a 60 watt flood display light, and aim it and the mandolin at a slight angle, you will see when you go through the overspray finish. Trust me when I say it's a slow process, don't rush it and check it against the light a lot as you proceed. Dampen the rag you are working with frequently too. I have tried pumice(sp) or rottenstone but haven't had the good results I got with Maguires. Good luck. Kenc

[sunburst]

Good advice from Ken.

It can be done faster by starting with fine sandpaper, but I wouldn't recommend that unless you have enough experience sanding finishes to be able to see when you are going from one layer to another. It is something you have to learn through experience, and not something you can see easilly.

If you don't have the experience to see the layers, it might be best to get someone who does to tackle the job.

[reb0964]

Also you may could use #oooo steelwool gently,,,it may help also but if rubbing too much may tend to dull the finish some,,,but a nice alternative to sandpaper at times

[buddyellis]

I'd use 2000+ grit sandpaper before I'd use steelwool. Steelwool can leave scratches that are hard to get rid of. Either go slow with the maguires or get you some 3m or micromesh in the 2-4000 range and go slow (You can probably wet sand with soapy water, but you might wanna test the finish first, otherwise use napthala). Either way, the going is slow.

[sunburst]

I wouldn't wet sand. I can see a layer interface almost immediately if I'm dry sanding, but not when I'm wet sanding.

Personally, I wouldn't use steel wool at all, and I wouldn't use any compound until I had all the overspray layer sanded off. After you're into the job a ways, you have areas of new finish, and areas of old finish. I feel like you want to keep as much of the old finish as you possibly can, and only with sandpaper can I selectively remove the old and leave the new, not with compound or steel wool. YMMV

Yep, slow going. I'd think in days or weeks, and not try to do the whole job at once.

[carleshicks]

I have had a couple of luthiers off the board suggest napthala or lacquer thinner on a small polish pad. they said just keep polising off the lacquer in small areas. Will this work and will either product damage the shellac bellow.

[sunburst]

I don't think naptha will do anything, and lacquer thinner can ruin the bindings. I don't think you'll find any short cuts.

Lacquer thinner can make a real mess if you use it as a stripper anyway. To me, that sounds like a nasty, smelly, chemical-exposing, respirator-wearing, glove-wearing way to do it.

[carleshicks]

Ok that is good advice. I am not really looking for short cuts I just want to leave the shellac finish below as untouched as possible. I might leave it to a profesional seeing how valuable of an instrument it is and leave me experiments for a less desireable mando.

[testore]

I've removed layers of polish from very expensive violins with several methods. My best suggestion would be to work under a black light. The two layers look different under black light and it's easy to see when one layer stops and another starts.I watched a Stradivari get done that way too. It takes a lot of time but maybe worth it in the end. Good luck