Freakin' Hell!

[TGwaH]

So there I was sanding my body done about thirty minutes ago. I had a bit of a run in the paint from the last coat, so I had to get rid of it. As I was sanding, the corner of the sand paper (was using 400 grit) caught a bit of the run and lifted the paint from the body. The paint did not adhere to the primer! I was stunned... angry... annoyed... pissed... you name it, I felt it. The auto paint I was using adhered very nicely to itself, but not at all to the primer. 2 weeks of work down the drain.

I'm pretty sure the problem lay in the fact I was using a crap primer -- Rustoleom "Painters Touch" from Home Depot. It's crap... horrible, will never use it again. Ever.

Tomorrow I have to sand it down to wood and was going to give it a crack with some automotive primer from Canadian Tire.

[Doc]

Don't blame the primer. One thing to remember with anythiing other than a lacquer type finish is that the bond between the coats is a mechanical reather than a solvent type bond. Lacquer redissolves the top of the undercoat and the stuff actually flows together. If you cut it and looked at it on end with a microscope there would be very little layering visible. Not so with stuff like paint or urethane.

Before you strip everything, stop. Let the thing cure another couple of days. Take a sharp x-acto type knife and see if you are still getting lifting. A run is many times thicker than the finish. Paint cure by rection with oxygen, not evaporation, so the inside doesn't cure anywhere near as fast. You may only have to feather in the edges, scuff sand the whole puppy and recoat with your top coat.

Some general rules of the road

1)Make very sure that whatever primer is bone dry. You will still be able to smell thinner even after a couple of weeks so this is no guage. Push our fingernail into it lightly and see how hard it is.

2)Scuff sand every square inch with a fine, not superfine, sandpaper. This puts thousands of teeny tiny scratches in the finish that the top coat can flow into and lock to. If you didn't sand it our real well and then tack cloth off the sanding dust this could have been your problem.

3) Check your can of finish and see what they recommend as a primer. Sometimes the best primer to use under a urethane is the same stuff thinned way down. A couple of coats.

4) As a general rule, and there are the odd exceptions, shellac will stick to almost anything and almost anything will stick to shellac.

5) I would make a test board. Take a piece of similar wood, or the same stuff if you've got it. About a square foot. Round one edge off so that you can see how an edge behaves, and finish the sucker just like your gonna do the guitar.

Hope this helps

[Mickguard]

Before you strip everything, stop. Let the thing cure another couple of days. Take a sharp x-acto type knife and see if you are still getting lifting. A run is many times thicker than the finish. Paint cure by rection with oxygen, not evaporation, so the inside doesn't cure anywhere near as fast. You may only have to feather in the edges, scuff sand the whole puppy and recoat with your top coat.

←

See my Bocaster thread in the project section (I think I spoke about this in this section too).

I had a massive run in my clear coat. I let that sit overnight. That way the surface of most of the guitar got pretty hard.

The next day I took a nice share razor blade and very carefully SLICED off the run. Because the surface of the guitar was much harder than the run, I was able to slice down to the surface without screwing up the rest of the finish.

The result wasn't perfect, but it was barely visible. If you let it dry a bit more, you could probably sand out the spot a little bit, and the run would be pretty much invisible.

The purists will tell you to sand things back and start all over again. I'm no purist --I'll believe in learning what you can on this project, then applying what you've learned to the next project.

[TGwaH]

First off...

idch, your Bocaster... killer. Does this mean that a pink fur covered Gretsch is next?

Doc, thanks for the help, but ultimately it was a no go. I waited about a four days or so beore attempting with the X-Acto knife, and the paint still lifted. Sadly the paint peeled like a bananna -- it came off in about 5 large pieces.

But I was able to start over, and and this point I am about half way to where I was before I had to strip and every thing is sticking nice to the guitar (different primer) and it is coming out much, much nicer than before.

Thanks for the advice Doc, and definately keep all your points in mind when it comes time to paint my next guitar.