They are called Pal nuts. They are stamped steel you need to measure the pin. They make all different sizes and types look for the acorn style that has a sealer so it doesn't hold water.Thanks for your replies. Great idea on the shrink tubing. I think those Marson kits are too rich for my taste. Like you said, I'll keep looking for them. In the meantime, I ordered a set of thread cuttting nuts for $14 that will at least hold the panel in place. Cheers