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I just repaired a Larrivee P-03 Koa parlor needing crack repairs and a lifting bridge to be removed and re-glued. I had noticed some, what appeared to be, wiped on clear something around the bridge but waited to address it until I cleaned it up after doing all of the work to it. When the repairs where done, I went after it with water based cleaners first with no result and then Naphtha with no effect what so ever.

I quizzed the owner if he had applied any type of finish to the bridge. He responded "If the instrument surface looks dull, I sometimes use a little violin polish (“Petz Polish”) to brighten it. Maybe this was the buildup you noticed? I’m surprised, I usually wipe it on with a bare hand and wipe off immediately with a clean cloth." I don't know what Petz Polish is but the wiped on looking haze around the bridge had quite a bit of lint stuck in it. I'm suspect of Petz Polish but it would make no sense that it would be safe on a violin finish but not on a catalyzed Acrylic Urethane finish(?).

I initially thought the finish to be poly, which is rather resistant to hotter solvents such as lacquer thinner. Rather than experiment, I contacted Larrivee to find out the exact finish used. They where quite responsive and I had an answer the same day. "Satin: Pure Acrylic Urethane 10% Sheen Satin Finish (Catalyzed), over top of a UV Polyester Basecoat".

A poly base coat with catalyzed Acrylic Urethane top coat. If it was just poly, I would have proceeded with something hotter than Naphtha but I have no first hand experience doing this with catalyzed Acrylic Urethane. Anyone have direct experience wiping catalyzed Acrylic Urethane with a hot solvent? It's a satin finish. I suppose if push came to shove, it could be sanded and buffed but I would have to do the entire top and it would end up with more sheen than it started with, not to mention all the extra work.

I gave the guitar back and I don't think the owner had ever even noticed the crap around the bridge. I may never have it back from him to do the clean up, if it can be cleaned up simply, but either way, I still would like to find out what solvents one could use on catalyzed Acrylic Urethane without damage to the finish.

i'd bet at one point the bridge started lifting and some one (with can do attitude) used epoxy to glue the bridge back down. when they did this, they cleaned off the squeeze out from around the bridge leaving residual epoxy around the bridge. on harder acrylics and poly, i will use industrial grade strippers like KS3, aircraft remover etc. you'll have to scuff sand the gtr first, but it'll work given time.

Thanks for responding but my client bought the guitar new and I am the only person that has worked on it. The bridge had never been off before I removed it and this person did not attempt any repairs.

The guitar was left at this person's office with no humidification. He was working from home and had not been monitoring the guitar, probably because he has other players at home. I'm in the Mid-West and we have had several occasions this winter of balmy days followed by plummeting temperatures, crack season. This guitar was VERY badly dried out, one of the worst I have rejuvenated. You could drop a coin through the top splits below the bridge. It spent 3 weeks bagged with 3 big Dampits in it to re-hydrate it. The bridge footprint was factory routed, leaving a margin of finish that extended below the bridge. In this case the finish margin under the bottom edge of the bridge seemed a bit excessive to me. I am blaming the lifted bridge issue on a minimal glue footprint and excessive dryness.

do you have pics? maybe the dealer tried to repair it? i would not like to think that, but i have seen repairs done that the customer did not have the eye for and the instrument was purchased "brand new" and no one ever fesses up to?! those are arguments waiting to happen though.Im sure a lot of techs have seen this. i call them the "self repairing instruments". some of them are from the instrument owners i'd have to think.

I don't have any pictures. The guitar was new in 2012. It first came to me in February of 2014 for crack repair after leaving it in his office unattended, developing a crack below the bridge. The stuff around the bridge was definitely not there at that time. As I already mentioned, I'm the only person to do any repairs to this instrument. Whatever is on there was something the owner did, it was not purchased that way. The guitar has been returned and I don't think the owner really cares, you have to look close and get the light at the right angle to see it.

I don't conjure up what if problems like this to just ponder, and would have no reason to wonder what solvents you could use safely on Catalyzed Acrylic Urethane, without first having an issue fall into my lap. I wouldn't recommend using a hot solvent on any finish without first knowing if it will do no harm. Now I have a need to know.

Well dang! Wished I could help but good luck. I’m outta ideas man. I just doubt that petz polish could have done that, but nowadays you just don’t know. Good luck