Yes, paper towel. When POR-15 came out years ago, I remember watching a demonstration at a swap meet where they used both a paper towel & fiberglass mesh.. A friend of mine was working on a small patch in a floor pan. He tried it out on a section he had already cut out. Painted, used a blue shop paper towel, thew it in the scrap pile and it was there for 6 or 7 years later and was just then starting to delaminate. POR isn't UV protected.
Since this was on the windshield pinch weld and only a short section, I felt the paper towel would work fine, followed by a very good quality seam sealer to finish out the shape, and I can install the glass/rubber without issues & leaks.
