Working on the interior of my 10's F/G top, which has lots of pinholes in addition to numerous other defects. I asked Barry at SPI for his advise. He said the key is to seal with the first coat with epoxy primer so the subsequent coat's solvents don't soften up the base coat and just keeps soaking in.
So, I put down two coats of epoxy primer and let it cure for 24 hours (the wait is a key part). 24 hours allows the epoxy to cure enough that it is imprevious to solvents and therefore locks in the base coat's stability. You could see the thousands of pinholes after the epoxy primer was on. However, they were concave depressions of the epoxy, which had bridged the hole completely. The SPI epoxy primer has enough thickness, or other properties, to bridge and not soak in. After 24 hours, I shot 3 coats of 2K high build urethane primer. Two probably would have been enough, but I had a variety of poly filler imperfections and 80 grit sanding scratches to get rid of.
After sanding tonight, it is perfect. Not a pinhole to be found or weave to be seen.
I know many struggle over this, so thought I would pass it along. In the past, I was putting the filler on too soon after the Epoxy primer and struggled with seeing the F/G weave through the paint.
Larry
So, I put down two coats of epoxy primer and let it cure for 24 hours (the wait is a key part). 24 hours allows the epoxy to cure enough that it is imprevious to solvents and therefore locks in the base coat's stability. You could see the thousands of pinholes after the epoxy primer was on. However, they were concave depressions of the epoxy, which had bridged the hole completely. The SPI epoxy primer has enough thickness, or other properties, to bridge and not soak in. After 24 hours, I shot 3 coats of 2K high build urethane primer. Two probably would have been enough, but I had a variety of poly filler imperfections and 80 grit sanding scratches to get rid of.
After sanding tonight, it is perfect. Not a pinhole to be found or weave to be seen.
I know many struggle over this, so thought I would pass it along. In the past, I was putting the filler on too soon after the Epoxy primer and struggled with seeing the F/G weave through the paint.
Larry
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