I recently purchased a 1919 Gibson A1 that has some top damage due to many years of playing without a pick guard. The spruce has been hollowed some between the hard grain lines and bare wood is exposed. First question is should I try to delicately try to add some finish to the areas of bare wood or just leave it alone? Second question is if I should try to add finish, what should I use?
Any other thoughts or suggestions would be appreciated.
Richard
Eastman 305
Gibson A1 (1919)
Martin D16 guitar
Great Divide Guitar (Two-Old-Hippies)
OME 11" banjo (1973)
Pisgah 12" banjo
Matching the top finish on a hundred year old piece of spruce is pretty much an impossibility.
Someone who is really good and highly experienced could brush a tiny bit of spirit varnish into the bare areas, just enough to seal them and keep them from picking up dirt. If they use too much, it will stick out like a sore thumb.
It's a difficult technique, requiring a high level of skill, a precise and steady hand, and a really good miniature artist's brush. It falls into the class of "Don't try this at home, boys and girls."
" ... should I try to delicately try to add some finish to the areas of bare wood or just leave it alone?"
This is very much a personal choice and can only be answered by you. In my opinion, which is worth exactly what you paid for it, it should be left alone from an aesthetic viewpoint, or it should be touched up from a preservation viewpoint. In other words, I wouldn't try to "correct" the appearance by touching it up, but I might wish to touch it up merely to slow the wear of the wood and preserve the spruce in the areas where it is already wearing between the grain lines.
" ... if I should try to add finish, what should I use?"
The luthiers and Gibby historians may have better advice here, but I'll offer mine anyway. I can't speak specifically to your mandolin, but in general, manufacturers of instruments and furniture wood products in 1919 were using nitrocellulose lacquer to do their bulk finishing of manufactured wood products. Lacquer dries fast and is a reversible finish which makes it relatively easy to correct and repair. So if I were to add some finish to the bare wood areas for preservation's sake, I'd use either (1) nitrocellulose lacquer, thinned and augmented with a little retarder, applied with a small brush, or (2) shellac, thinned (cut) with a good grade of alcohol and likewise carefully brushed on.
The idea there is to slow the wear, expecting the possibility of more wear in the damaged areas, rather than trying to restore the finish to a pristine condition, or to refinish entirely.
Edit: A true expert has beat me to the punch while I was typing and recommended spirit varnish ... I'm a professional finisher, but not a luthier nor an instrument historian, so I would definitely defer to Bob (rcc56), and of course a pro would be better suited to applying the finish, but it is not beyond a skilled hobbyist IMHO
I would consider it important to use a fine brush and add finish only to the bare wood areas. Again, this will do little for the aesthetics of the instrument ... notice the darkness around the damaged areas, that is due to body oils and dirt ... etc. ... again, heed Bob's warnings. I would do this for preservation if I thought it really necessary, without regard to aesthetics.
Last edited by Mark Gunter; Jul-04-2022 at 1:29pm.
Reason: Add'l commentary
While we are not sure exactly what kind of varnish Gibson was using in 1919, most of us agree that it was indeed varnish and not nitrocellulose lacquer.
While there is also debate about exactly when Gibson started using nitro, most of us agree that it was no earlier than 1925.
I use shellac based varnishes on instruments from this period. I use pure grain alcohol for a solvent, and get my shellac flakes and other materials from a violin supply house.
I'll quote our old friend "Sunburst" here: It's easier to make it look worse than it is to make it look better. Few of us are really good at touch up work.
Not to be too contrary here, but fixing the finish on those old mandos is not impossible, although it is a case of "do not try this at home" (as was said) unless you have developed the skill through experience.
The "washboard" surface can be filled with something clear (shellac, resin, perhaps other if originality is to be ignored, and it already is when touching up finish), the color touched up using dyes to match the aged top, then the entire top can be french polished by someone good at that procedure.
If it was my mandolin I would leave it as is, but if I had to fix it, I would fill the washboard as stated, touch up the color and french polish, and most likely turn it over to a FP expert after becoming frustrated with my own FP attempt. I also might resort to spraying spirit varnish. Once the varnish is in place we can't really tell how it got there after all.
As for good clear fillers, if we are ignoring originality, I've had good success with epoxy, thick CA and UV cure fillers. It often doesn't take much because the depth of wear in the spruce is usually not as bad as it looks. Sometimes several coats of super blonde shellac, sanded between coats, will do the trick.
I probably should have said that my purpose is to preserve the wood, not make the finish look better. If wood preservation is not a requirement, than I will most likely leave it alone. Thanks for the advice so far.
Richard
Eastman 305
Gibson A1 (1919)
Martin D16 guitar
Great Divide Guitar (Two-Old-Hippies)
OME 11" banjo (1973)
Pisgah 12" banjo
As stated they usually look deeper than they are and I personally like its looks, if it’s all original anything you do with the finish will decrease its value so a pick guard would probably be your best option.
Pappy, I do recommend that you install a pickguard.
Cumberland Acoustic makes an A-5 style guard that sells for $180 direct from them. It is not an exact replica of a teen's guard, but it will work. A smaller "Abbreviated A" pickguard is also available in unbound celluloid for $90.
Or, if you prefer something that is more period-correct, several of us, including myself, can make one for you. Since cam clamps are not available, we would have to employ a different type of clamp. Most of us use a modified viola chinrest clamp.
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