For those who haven't use the Zinnser Watertite paint as a canvas filler, good. DON'T! Think about this: It's got concrete in it. Concrete. Heavy, and NOT FLEXIBLE. To put this stuff on canvas, on a cedar, both of which flex, is not right. Why am I postinging this? I just finished sanding down a layer of the product, on canvas, on a cedar canoe, and when done, I found cracks all over the finish! Of course the paint doesn't flex when it's dried, it's not designed to. Anything that's going to move beneath the cement like paint is going to cause the cement like paint to crack. Nothing's going to fix the cracks now except new canvas. I post this to hopefully save someone else the cost, time, and pain of having a good job ruined.