Official Luthiers Forum!

Hey folks.

So i not long ago finished number 10 which went off to a very happy customer... only thing is he has now go back in touch, 2 months later, to say that the top has developed significant cracks in the lacquer all over (see photo for sample).

He say this happened after taking it to a camping jam, at which it was very cold, and there was a fire, which he admits playing in front of. So i'm 99% the fault is on him for playing too close to the fire and then (probably) stepping back into the cold without adequate re-acclimatisation.

He fully admits that this is on him, that he should have been more carful, but i'm wondering a few things that i would like answers to if you kind folks have the time -

1. Is there much precedent for this, anyone else had this happen?

2. Is there a chance that because the guitar was relatively new that is was more vulnerable. (for the sake of facts the lacquer had a full month of curing before being buffed out, then this happened 2 months or more after that)

3. Is there any kind of fix other than stripping and respraying.

4. As it is on him, he has offered to pay to have me make it right... how much would your guys charge for this?

5. Any other tips or comments that might help me deal with this.

Thanks alot guys... i really appreciate the help... my heart is broken a little.

Gary.

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www.leddingtonguitars.com

Hi Gary,
Most lacquers react that way when treated to extreme temperature changes. A thinner film and a lacquer with more plasticizers tolerate it better, but even they have their limits.
If your friend is the type who likes to play around the camp fire I would suggest you convince him to live with it and enjoy the guitar as it is. Many of the well used "vintage" instruments have cracks in the finish, often highlighted by dirt and dust. It is a rare instrument that when played around a group of people doesn't eventually sustain some finish damage - and often worse things happen - cracks, and dings, and dents.
Stripping and refinishing is quite a bit more work than the initial finishing so I would charge twice the price of a finish job.
Brian Howard can advise you better as he has done finishing professionally.

I would also encourage your customer to live with it. These days, people pay extra for that...

Bummer! And it looks exactly like a guitar that went out of my shop last year. Only to immediately get finish cracks. Quick temperature changes and too thick a finish. I feel your pain. New spray gun and I was definitely not tuned in to how much I was laying down. As others have said, refinishing is more work than the original finishing, remove neck and bridge if you are going to do it. And there's the risk of changing the sound if you over sand the top while stripping the old finish off if you are over aggressive with sanding. Good luck with whatever you choose to do.

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Tony Thatcher
Bozeman, Montana

I had this same campfire experience in 1977 when I had just finished my first guitar. I opened the case next to a roaring campfire in Eastern Washington when the temps were in the low 40's. There actually was an audible sound as a several inch long crack appeared in the finish. The finish was Mohawk nitro lacquer.

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“ The meaning of life is to find your gift and the purpose of life is to give it away” Pablo Picasso

I would also suggest having a conversation with the client. Let him know there is no harm to the instrument and vintage guitars often show lacquer crazing as it inherently shrinks over time and gets exposed to temperature variations. His guitar got a head start. If he wants to enjoy the guitar camping, and in front of a fire, he should do just that. Won't harm the guitar within reason. No cost for him. No real damage to the guitar. No risk for you doing a strip and refinish of the top. Everybody wins.

Ok... thanks for the tips so far guys!!

I'm really sure i did not spray too much lacquer.... about 12 layers sanded in between.

G.

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www.leddingtonguitars.com

You probably did everything right. Even a perfect lacquer job can't tolerate being shocked by temperature extremes. If your friend insists on refinishing the guitar, I would suggest you give him the name of one of the people who do that. When he finds out that it isn't cheap and easy he may decide to live with a few finish cracks.

Yes these things happen. Some formulations are more prone to this and some pigments can make it happen easier.



No, fresher lacquer is softer and more resistant to checking. The older the lacquer is the more susceptible it is to crazing.



Yes. Since it is fairly fresh you may have some success with applying some retarder and reducer mixed and re-amalgamating the film.This will re-wet the lacquer and allow the cracks to flow shut and reform a continuous film.



To wet out with retarder would be about $300 if it works (no guarantee on this) and around $500 to refinish the top. But I suspect if the top is crazing the rest is likely already started crazing or will shortly so a complete refinish may be in order. I get close to $1000 for a nitro refinish these days.....



Consider abandoning nitro for a more modern finish that will not do this like UV cured poly....

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Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Cool... thanks guys... i certainly feel a lot better.

Brain thanks especially for taking the time to answer my individual questions.

G.

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www.leddingtonguitars.com

Go Brain!

If you have not had the pleasure of taking a functioning guitar back down to components, now is the time. If the checks are in the top finish only, pull neck, bridge, and pickguard, strip the lacquer with standard or extra-strength paint and epoxy stripper (stay off any plastic and avoid multiple applications over glue lines), prep, and reshoot with a thin finish. If the entire finish is checked, then strip everything and make the call on alternative finishes versus a thin lacquer finish.

The worst thing about this sort of work is the opportunity cost - the time required to strip and refinish one instrument will likely be equal to the time required to finish and assemble 2-3 similar instruments, so best to ensure the estimate for the work is based on the full loaded shop rate if not done under warranty (and it sounds like this was not a covered incident).

If the checks are few and far between, it's always an option to use butyl cellosolve and thinned lacquer to spot repair, but it seems to us as though once finishes cold check, they continue to throw checks over an extended period (the thicker the lacquer film, the worse the issue), so opting for the full top refinish might actually save the customer money versus multiple cycles of patch and polish work.

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For the times they are a changin'

- Bob Dylan

Another reason the repair - be it spraying any kind of finish components or doing by-hand spot touch up on the top is not a good idea - is that the level of expertise required to end up with a repair that is not visible is substantial. By the mere fact that the OP posted this question likely indicates that he's not pulled 30-40 bridges on guitars, and done finish repair on an equivalent amount of tops AROUND BRIDGES. To perform without leaving a trace of the repair, is not work for the meek.

A finish repair is not always a finish repair, and cannot be looked at through the eye of a spray gun. Getting that finish right around the bridge is a very non-trivial exercise and fairly advanced work. With the alternative being removal of the bridge and neck, performing a complete top refinish, also a pretty complicated repair and more risky repair for someone without significant experience doing such. Remember the end result objective is a perfect guitar where the work is not evident.

The better bet is to consider the complexity and risk of getting to a better end result that exists now (which at least looks like some natural lacquer checking) than when you proceed to dig a hole to China on a client's guitar, without having gone down that hole many times before to know the trade-offs, techniques, gotchas, etc.

Often people do not realize that guitar repair is a second order problem - side effects are the devil.

Wow, looks like a gorgeous, top shelf sitka spruce soundboard! Question. Isn't lacquer one of the hardest finishes one can use? If it's that hard, it surely doesn't expand and contract like wood. And you know wood is always moving, albeit slowed down when the sealed with a coating.
So is laquer even a good choice of finishing product for guitars? My sons use poly urethane on their deer calls. Though they are small, they get exposed to EXTREME humidity and temperatures changes. Humidity of saturation from outright rain to hanging on the wall by the wood stove. And that type finish doesn't crack. So I am curious.

Brent—

Tradition is a powerful thing. Nitrocellulose lacquer has been the main finish material used on higher quality factory acoustic guitars since the 1920s. There are now arguably better finishes overall, and definitely better finishes in terms of avoiding this particular hazard. But because the iconic guitars we all revere had nitro, lots of folks want nitro.

Yep tradition..... pretty near impossible to sell violin builders even the finest old growth sitka spruce fronts.