"check" this out...

If you have a string instrument of any kind that needs fixing, a mistake you made in building a new instrument that you need to "disappear," or a question about the ethics of altering an older instrument, ask here. Please note that it will be much easier for us to help you decide on the best repair method if you post some pictures of the problem.

"check" this out...

Postby Ryan Mazzocco » Wed Feb 10, 2016 7:01 pm

I've been using a pre-cat lacquer on my last several guitars. I keep having a problem with it checking, but only on the face of the headstock. The last run I gave away to friends and family so I didn't bother fixing it, but I did some research and took note of what may have been causing it. It seems I may have sprayed too much at once. This time I made sure to be more careful and spray lighter coats. Here's the deal. I'm trying to bury my decal logo, so the finish on the headstock is thicker than anywhere else on the guitar. So.... it checked again. There are several hairline cracks on the face. I attempted to fix them by using a method outlined on frets.com, but it didn't work. My feeling is that it didn't work because it's a pre-cat and not a true, pure nitro. It didn't seem to want to melt back into itself and ended up looking no different than when I started.
Just for reference here is the lacquer I've been using. http://www.gemini-coatings.com/index.php?architectural/products&a=&product_id=37 I've been using it because with our account at the local paint store we are able to get it quite cheap. Also, I figured it could be built up quite thick since it is described at being furniture grade. But further research I've done this time around suggests that pre-cat has other additives that make is much less flexible. So, it would seem that as it cures and shrinks it's just popping anywhere it can find relief.
So, here's my new plan... strip the headstock, replace the logo (since the current one will be ruined in the process) and refinish with straight nitro, maybe Behlen. But I'm wondering if this could cause a problem with the other lacquer. I plan to mask everything off except the face that I will be refinishing, but if it should come in contact with the original around the edges I'm worried that it might cause some trouble.
Does this sound like a good plan? are there other pitfalls I could be getting myself into that I am not aware of? Is there a better solution?
As a side note, This was the last time I was planning to use this lacquer anyway. It was just convenient to get it at the time. But I plan on switching to Cardinal from now on.
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Re: "check" this out...

Postby Barry Daniels » Wed Feb 10, 2016 7:08 pm

You are correct on two things: 1) Just because it is furniture grade does not mean it can be built up real thick. In fact it is quite the opposite. Most furniture has no where near the thickness of finishes we use. And many furniture lacquers (even high build lacquer) will check when built up thick. 2) Because the finish cured by catalyst, it will not dissolve and remelt when thinner is sprayed on.

I think your plan should work.
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