Double Bass Improving finish

[Buffalo Sam]

I just got a 1940's German bass and it's got some marking of the finish that looks like something [alcohol?] was spilled on it. Tried guitar polish on the whole instrument and got dirt off, but the marks were still there. Tried mildly soapy water too, but no luck. Anybody know what kind of finish might have been used in the late 1940's-early 1950's. Any advice on getting this better looking?

 

[eh_train]

Hey Buffalo,

I'm guessing it isn't part of the original finish, but something added on top of the finish at some point. You've tried polish and soapy water, so you need to move on to other potential solvents.

I'd highly recommend trying some vinegar on a paper towel. It will remove white glue and carpenters glue very nicely and shouldn't damage the original finish (but you can test for that by trying it where no one will notice - like next to the endpin). If it doesn't react with the underlying finish, just soak the paper towel in kitchen vinegar (which is already highly diluted) and leave it on the stain for 10 minutes or longer. If it's wood glue, it will soften and rub off fairly easily.

I just finished taking off a bunch of ugly stains this way on a light coloured bass. It had been badly glued together using wood glue, and I guess the "crafstman" (or woman) thought "no harm in rubbing the extra glue into the finish". (***?!?!)

Anyway, I would try this next. If that doesn't work, you can move on to trying something else. I'm sure others will have suggestions.

Hope this helps,

Paul (eh_train)

 

[misterbadger]

Mineral spirits were recommended to me for cleaning up gunk (mostly a heavy rosin buildup)on my varnished bass - safe, but didn't do much. I resorted to 3M's spray adhesive remover (after, of course, trying a test spot by the endpin) which did the job and didn't affect the finish at all. It's a citrus-based product that I use extensively at work and have never seen it damage a finish. On my lacquered late-40s bass, Meguiars' "PlastX", made for polishing out plastic headlight lenses, cleaned off 65+ years of accumulated crud nicely. It contains a very mild abrasive, so use caution. Always test first!

 

[Buffalo Sam]

Mineral spirits were recommended to me for cleaning up gunk (mostly a heavy rosin buildup)on my varnished bass - safe, but didn't do much. I resorted to 3M's spray adhesive remover (after, of course, trying a test spot by the endpin) which did the job and didn't affect the finish at all. It's a citrus-based product that I use extensively at work and have never seen it damage a finish. On my lacquered late-40s bass, Meguiars' "PlastX", made for polishing out plastic headlight lenses, cleaned off 65+ years of accumulated crud nicely. It contains a very mild abrasive, so use caution. Always test first!

Some new information. Tried the vinegar as suggested, but no luck. Then I called a luthier friend and he suggested trying some alcohol on it to see if it was shellacked or french polished. So I got out my 99% isopropyl alcohol and tried it in a couple of spots. Sure enough it got tacky. Rubbed it out a little and the haziness went away and it came back much shinier when dry. So we're going to get it over to his shop and we'll french polish the whole thing to get it better looking. I'll let you know how it turns out.