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Can someone confirm or deny what John said about hot cooating with polyester resin? I thought that if you allow it to cure in between layers, that you had to sand in between. Hope someone knows, because I guess I really don't.
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We are talking regular polyester layup glass, not epoxy or vinylester, right?
If so, this is what I have experienced. I like the "tighter" lamination that hotcoating gives, and it uses less resin, etc.
The down side, is this, sometimes....
If you hotcoat, and put a lot of glass up at once, lets say 1/4" or more in total thickness, and if the weather is warm, the stuff will get hot. Part of the curing process involves outgasing, and from time to time, I have had glass bubble "air pockets", actually outgasing underneath. It doesn't do it every time, but if the ambient is above 70 degrees, and you mix the stuff at ratio, or too hot, and it is in the sun, it will bubble, especially where it is thick, in corners/etc. Not all the time, but it will from time to time. I have seen this in SeaCraft hulls, on the chimes, it looks like they throw a lot of resin in those tight corners, and I have seen a fair number of voids right there. I am not sure if this is a tight corner issue, or a outgasing from heavy layup, but I have seen this in other boats too.
That is one of the reasons I use epoxy. The MOS stuff from BoatUS and the Marine Epoxy from BoatBuilder Central DOES NOT blush. West and some of the others DO. Most Vinylesters that I have used do too.
Hope this helps, and I hope others will offer their experiences for you.