Hatch is done. LONG story. I found out that you can "B stage" vinylester (stop and restart cure with temperature), and that you can dry out 1708 with just peel ply, a LITTLE pressure and a week long cure.
I was glassing and the temp and humidity was rising. So I kept dropping the hardener. The last layer, I diluted the resin with ~10% styrene monomer and dropped the MEKP to the slowest cure (5cc/ qt). Then the ambient temp crashed and the humidity skyrocketed. The temperature dropped to 55F in 18 hours in my workspace, and over the week dropped below freezing. After a week I had resin that was between tacky and genuinely wet.
But Joe Merton mentioned that the vinylester will cure in sunlight to a degree, so I decided to finish the part in a solar oven consisting of two layers of poly drop cloth. I threw it on the back lawn. The UV and heat restarted the cure, and I wet out the slightly dry cloth with a bit more resin. Final cure/postcure temp was probably 140F. It was a learning experience where it was harder to work with the mat than the 1708.
Something unexpected- 1-1/2 oz mat is stiff until resin gets to it, so getting it in corners was actually harder than the 1708, at least in this case.
Also, no guarantees on resin strength, but that hatch probably has 2 layers of mat and 2 layers of 1708 topside, and half that on the under (bilge facing) side. It sure is stiff and kind of rings when you tap it. I am happy enough as a learning experience with the foam. Which was the easy part, this time.
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