Question about Nitrocellulose lacquer

[multidon]

There is something about nitro lacquer that has been bothering me for some time now. One of the big “advantages” of a lacquer finish that is touted is its “repairability”. The theory is, that if something happens, like a chip, ding, scratch, crack, or other flaw, it can be repaired because the new lacquer “melts in” to the old. If I’ve heard that once, I’ve heard it a thousand times. But then when something actually does happen to the lacquer finish, we are told we shouldn’t try to repair it, that we should leave it alone. And as for the ultimate lacquer repair, the complete instrument overspray, which theoretically should melt in with the old and become one with it, we are told that is a big no-no and that if it’s done on a high priced instrument, it cuts the resale value in half! Gibson themselves used to do oversprays as a matter of course when instruments came in for repairs, didn’t they? If it’s so bad, why did they do it? And what is the use of going on about how “repairable” lacquer is when you can never take advantage of that advantage?

[Mark Gunter]

But then when something actually does happen to the lacquer finish, we are told we shouldn’t try to repair it, that we should leave it alone.

Don, the way you pose this gives the appearance that everyone agrees about all this advice you're rolling up into your question. To back away from that, and simply discuss the repair-ability of a nitrocellulose lacquer finish, I'd say that I have made thousands of virtually invisible repairs to lacquer finishes for 40 + years, a very small number of which have been on musical instruments. The subject of film finish repairs is a very, very broad subject. You don't successfully give advice or explain an entire course of education on how to do it all in internet forum posts.

When people ask their questions here about how to repair or should they repair certain things, they're going to get advice from perhaps some great luthiers, great finishers, and anyone else who feels like giving an opinion. They'll get conflicting advice. Some may be better than others. And, if a person takes the very best of the advice, there is no guarantee that he or she is going to pull off a successful repair.

So if you're reading a whole lot of "we shouldn't try to repair it" on internet discussion boards, well, neither do I find that surprising nor do I believe it's in conflict with the fact that lacquer finishes are easily manipulated and reparable by professionals.

[fscotte]

Lacquer is easily repairable, so easy, even your wife can do it.. Or you, if you wear nail polish.

What makes it difficult is people dont give lacquer the time is needs to shrink and cure, thus leaving a dimple or dibit as I call them. If the ding gets into the stain and shows bare wood, that's a little more difficult to match the color and intensity.

Sometimes the easiest way to repair a mark or ding or scratch in the lacquer is to sand away the scratch with 600 to 1500 grit wet sandpaper and buff back to a shine with your favorite Meguiar's formula. Provided, the lacquer coat isnt super thin and you have enough to sand away to buff.

If time is of the essence, you can use clear nail polish. It dries and cures fast with less chance of a dibit.

[multidon]

Mark, I thank you very much for your input. Perhaps it is true that not everybody agrees and it’s a very broad subject, but I stated the seeming inconsistency as best as I could. I have been a musician for a few decades now, and I have owned literally hundreds of instruments over the years. Based on many years of involvement in the world of musical instruments, it seems to me that there s a “collective wisdom” on those two points. One, lacquer is easily repairable. Two, even though it can be done, it shouldn’t. Now, everybody may not agree with those points, but I’ve been around long enough to know that these truisms get repeated a lot. And I don’t just get my information from the internet, either. I do know and have talked with other musicians, hobbyists, luthiers both amateur and professional, and enthusiasts. I also read books and magazines, a real throwback I know. The overwhealming evidence is, in my experience, is that there are sizable numbers of people who believe both of these things even though they are at odds with each other. As for “we shouldn’t try to repair it”, all you have to do is look at the value of a “collector grade” instrument that had not been oversprayed versus one that has to know what instrument collectors think of repairs. I have seen professional musicians playing old Martin and Gibson guitars that are so worn, half the top is bare wood! To me, bare wood is bad and an overspray or something to seal and protect at least would be an improvement. But I don’t think I would be in the majority on that assessment.

[MikeEdgerton]

Frank Ford's article on repairing Lacquer is here.

I've done a couple of small repairs that didn't turn out well and that was probably due to my own inexperience.

[Mark Gunter]

I stated the seeming inconsistency as best as I could ... it seems to me that there s a “collective wisdom” on those two points. One, lacquer is easily repairable. Two, even though it can be done, it shouldn’t.

That's fair enough, Don.

Well, I know that I see many questions in the forum about stuff that I believe I could easily repair, but I don't answer anything because it's difficult to explain to someone what to do, and they're gonna get opposing opinions what to do, some maybe informed and some less so, and as I wrote above, even if they attempt a tried & true method they may flub it up for lack of skill or understanding.

Beyond that, it's an interesting question why I would make repairs to some things and not others as regards my own instruments. I play a 1949 Patrician archtop that has some bruises, and I can't bring myself to repair most of them. All I've done for most of the finish on that is clean & polish. Another guitar I play frequently had a chunk wore out at the edge of the soundhole from fingernail. On that one, I just brush a little lacquer into it. On others, I've done burn-in repairs to gouges, and on some total refinishes.

I think a lot of variables go into why a person does or does not repair a finish on his instrument, far beyond the "ease of repair-ability" of the film finish itself.

[Wrnchbndr]

Lacquer never totally dries out. It continues to vent solvents forever until there is little left other than the pigments. Different recipes for lacquer over the years age differently too. But always, the thickness of the finish gets thinner and thinner over time and what was once maybe a mirror gloss eventually begins to reveal the surface contours of what ever is underneath it. It shrinks and shrinks and if the same original lacquer remains of the entire instrument, there will be a wonderful unbroken character to the whole. It also changes color. The medium ambers and changes blues to green and reds to shades of orange. Old pigments change or fade into colors that are quite different from when they were new.

There are different perspectives in this discussion. A vintage instrument has a beauty all its own when it is in its original untainted aged and worn condition. The micro-checking of the finish and the dings and dents are all elements of its authenticity and age and they are things that you can't (IMO-shouldn't be able to) buy. The appreciation of this sort of thing isn't shared by everyone to the same degree and that's cool too. Its a matter of taste.

If I had a client with a valuable instrument come into my shop because they accidentally put a ding in the finish, as long as it wasn't a structural issue, I would probably advise them to leave it alone. Reasons behind my advice: 1. Although I have skills, sometimes a finish repair can go south and the repair can be more of an eyesore than the original damage -- it can happen despite the best intentions -- finish repair is risky. 2. Even if I succeed at an invisible and totally successful repair, the new lacquer is young and in one year the new lacquer will have aged at a different rate than the original lacquer. At best, it will be a small yet noticeable difference. This defeats the entire reason for the repair. I could refinish the entire instrument but this is a very expensive proposal to my client, a high risk job for me, not something I want to do, and not a good economy for my client who is most likely going to put another ding in their instrument in the near future. Instruments that are played all get damaged or worn eventually. 4. The vintage market favors instruments in original unmolested condition and the fewer the repairs the better position of the seller. This is just a fact. During a transaction involving a vintage instrument, the buyer will use any and every reason to degrade the potential value of the instrument to get a better price. If the instrument requires repairs, these can be done at the discretion of the new owner. But if there are repairs that have already been done, they can't be undone. There is latitude if there are repairs needed. There is no latitude if the repairs have already been done. The market encompasses are larger group of potential buyers if the repair is not done because those who want a totally original instrument with dings and dents are happy while those who want something in better condition could choose to have the instrument repaired.

All of that said, if you "want" to do a cosmetic repair to the finish, lacquer is the most forgiving of any finish I've worked with. When necessary, after a structural repair, I do fairly well when the original finish is lacquer and as a rule, the result is far better than if I need to repair a modern finish. I just choose to not engage finish repairs unless its necessary.