I think you just solved an issue I was having with my epoxy not wetting out well. I always rub down with alcohol before I epoxy just to get every bit of dust out of there, then wipe with a tack cloth before epoxying. I let it dry but only for about an hour. On the last one I did I didn't wait too long after the alcohol. I wonder if that was the problem. I just built a wood surfboard and just wiped with a tack cloth and had no issues at all. In fact, it was perfect. I didn't have any bubbles to go back and fill, or any parts where I said "Gee, I guess I can live with that little blemish." Best wet-out I ever did. I have never used 4 oz cloth before. Always used 6. I love the 4.