I used it with glass cloth on an old lam to test it, and it worked great. It penetrated better then bowgrip or smooth on. It isa tad thinner than smoothon. Reason is because smoothon thickens a little more with cabosile. If you like a thick epoxy, the 400/11 is real thick, I tested it as well. It worked good too. I was a bit thicker than smooth on. To get something between, you could get a cheap lb of cabosile and thicken the 300/11. They sell cabosile real cheap and a lb bag will last a while. I really like the consistency of the 300/11. And since it is half the price of smooth on, you cant go wrong.