ihocky2 Posted April 15, 2008 Report Share Posted April 15, 2008 I am in the process of sanding out and polishing my Warbird build. I have it down to 1000 grit and had to let it sit for about a week or more. I started working again tonight and noticed a bunch of little cracks through the finish on the side of the body and a big one on the front that runs between the two pickup cavities. I am not sure why this suddenly happened. I used the Sherwin Williams Conversion varnish on this body. It was painted back in January, but has been kept indoors in 70 degree weather the whole time. It has been kept away from the windows or the heat vents. I know that I am not going to be able to fix this without stripping the body down, which I am going to start tomorrow. But I wanted to find out why it happened. This is not the greatest picture, but it shows the big crack. And even more annoying is that it is not along a glue line, that is only solid wood. Quote Link to comment Share on other sites More sharing options...
rhoads56 Posted April 15, 2008 Report Share Posted April 15, 2008 Used water while sanding?? Water soaks in through sections where the finish isnt covering the timber and makes the wood expand. Quote Link to comment Share on other sites More sharing options...
ihocky2 Posted April 15, 2008 Author Report Share Posted April 15, 2008 I only use either mineral oil, or mineral oil thinned with mineral spirits anymore. I gave up on water over a year ago when I got tired of plugging all of the holes just so I could wet sand. Quote Link to comment Share on other sites More sharing options...
fookgub Posted April 16, 2008 Report Share Posted April 16, 2008 How many coats did you apply? I had the same problem with CV, only worse. I think my issue was too many coats total (6 wet coats) and applied too rapidly (3 coats a day one hour apart on 2 consecutive days). Sherwin-Williams recommends a maximum thickness which works out to about 2 coats. Also, I used shellac under the CV, which I think was a big mistake. Unfortunately, you're looking at a total re-do. I can tell you from experience that it will crack more. I will be refinishing both of the guitars I did using CV this summer. I will probably just use nitrocellulose lacquer, but I'm considering precat, too. Quote Link to comment Share on other sites More sharing options...
ihocky2 Posted April 17, 2008 Author Report Share Posted April 17, 2008 I stripped it already and have pretty well determined that it was from being sprayed on too thick. I ended up with about 8 coats I think. It didn't really seem like it was building that heavy at the time. When I used the heat gun and stripped it yesterday the stuff was pretty darned thick. After I had two or three coats on I could still see the pores pretty well, so I figured it wasn't building that well. I think you need to go with more than the 2 or 3 they recommend, but only a couple more. I'll have to experiment more over the summer. I am probably going to respray tomorrow with 2 part poly. I got a lot of good advice and recomendations from the guys at the auto body supply, so I think it will turn out pretty nice. Quote Link to comment Share on other sites More sharing options...
fookgub Posted April 17, 2008 Report Share Posted April 17, 2008 I stripped it already and have pretty well determined that it was from being sprayed on too thick. I ended up with about 8 coats I think. It didn't really seem like it was building that heavy at the time. When I used the heat gun and stripped it yesterday the stuff was pretty darned thick. After I had two or three coats on I could still see the pores pretty well, so I figured it wasn't building that well. I think you need to go with more than the 2 or 3 they recommend, but only a couple more. I'll have to experiment more over the summer. The CV builds much faster than lacquer. Even at six coats it was much thicker than any of the lacquer finishes I've done. I'll probably relegate CV to necks and natural finishes, and stick to 2-3 coats max from now on. How did you mix your finish? You can have a lot of problems if you don't get the mix ratios right. I used a graduated syringe to mix in the catalyst. Quote Link to comment Share on other sites More sharing options...
ihocky2 Posted April 17, 2008 Author Report Share Posted April 17, 2008 I used a few different syringes, depending on how much I need to mix. I think I was using a 10cc, and a 30cc, along with a painters mixing cup. So I know I had the mix very close to dead on. I think I am just going to have to experiment more with it over the summer since I can start spraying again outdoors. This guitar is actually for a friend, so I am glad I got too busy to polish it out right away. I would have hated to have finished it and given it to him, to have it crack only a few months later. If you haven't stripped down the two guitars you have to refinish yet, I can tell you a heat gun a scraper does a fantastic job. Only the slightest bit of residue is left. I think it took me 2 or 3 minutes of sanding with 100 grit on the random orbital to get the front and back totally clear after scraping. Quote Link to comment Share on other sites More sharing options...
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