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Hey all. I have a bolt on Firebird body...mahogany with a spalted maple top. The previous owner didn't harden the spalt with any sort of wood hardener or epoxy. Just sprayed on two coats of sanding sealer and two coats of satin nitro. Needless to say, the top is very soft/flaky in spots with some dings and cracks here and there that need to be filled. I've read a bunch of suggestions that you need to prep spalted maple with a wood hardener or pacer z-poxy works well. The question is....since the body was already sprayed with a sanding sealer and nitro, what do I need to do to make sure the hardener or epoxy soaks into the spalted maple? I assume I need to rough up the finish that's on it but I hate to sand it too much with the spalt being pretty fragile. You can barely tell there is any finish on it at all but I want to make sure this body gets hardened up good before I do any finishing. Any tips and or advice would be much appreciated. Thanks in advance!
Jared

great looking body. just need to get the spalt hardened up...

thanks for the tip! so you recommend stripping it all the way down to bare wood? didn't know if i needed the z-poxy to soak in or just build a hard coat over the spalted maple to protect it.

I would definitely try and harden the wood, otherwise it will flex under the finish with any sort of impact and do the same thing you're describing, or at the very least crack the finish easily. Generally in finishing it is a bad idea to put a hard finish over a flexible surface

yep i agree. that's why i'm stripping it down to epoxy the spalt. i used acetone and a rag it it's taken the lacquer right off. do i need to avoid the edges of the body with the acetone? it shouldn't have any affect on the glue joint right??? where the spalt is glued to the mahogany i mean. i also plan on binding the top edge of the body. another reason i need the spalted maple nice and sturdy

I think you'll be fine with the glue, the only solvents that can bite into wood glue are xylene and toluene as far as I know, so stay away from "goof off" and you should be fine.

thanks for the info on the solvents. i wasn't aware which solvents could harm wood glue. step one is done. i was able to strip the sealer and lacquer and get it down to bare wood by brushing on acetone and wiping it down with a rag. no issues anywhere that i can see. next step is to fill in the deeper dings/cracks with a thicker, clear epoxy and then seal the whole thing with the z poxy. hopefully that will seep in nice in the spalt and get that top sealed and hardened up. and that will also get the mahogany grain filled too. wish me luck, gentlemen. never had to do this before so this is something new for me. hopefully it goes smoothly. should be a gorgeous bird when i get her all done. i'll post some follow ups and probably some more questions:) thanks again....

I don't have a ton of experience with epoxy but I've seen other guys talk about thinning it out with Denatured Alcohol (I think). Might be a good idea to thin out your first coat to get a little better penetration. I've used CA glue to harden spalted before but it was a much smaller area than what you've got. One of my other hobbies is growing and creating bonsai trees, which can sometimes include dead wood elements that are exposed to the weather. We often use a compound called lime sulfur to preserve the wood and keep it from rotting out, but it has the unfortunate side effect of bleaching the wood, okay for bonsai but wouldn't be good for your guitar. Awhile back I was looking for an alternative and found a product that is used in a lot of art preservation, it's called Paraloid B72 and is apparently soluble in acetone, toluene and alcohol. I don't have experience with it myself but it's supposed to penetrate wood quite well, doesn't yellow with time and can be mixed to different viscosity depending on application needs. It's pelletized and dissolved by the end user much like shellac. Might be worth looking into?

oh and here's another product specifically made to harden rotting wood

http://www.pcepoxy.com/our-products/woo ... rifier.php

thanks and yep, i read that too about thinning with alcohol. might try that on the first coat just to get a feel for it. funny you linked me the pc epoxy. i was in home depot today and looked at their wood hardener. thought about using that too. i used some water like super glue on the edges of the neck pocket and other top routes just to see what it would do. soaked right into the maple and made it much harder than before. wouldn't want to do the whole top with that but it seemed to do what i wanted. i'm gonna look into other options before i try the z poxy but i feel pretty confident with that product. never used it but a few guitar builders i know use it often for grain filling/sealer and have said it's really easy to work with and sands easily too which is also nice. i'll check into the other options you mentioned and see what i can find out about them. thanks again. i appreciate your time and info!