Seems like this is the subject I write most about... I mudded an Otca over 7 weeks ago. Yesterday I took it from under the deck & tarp where it went to dry and into the garage. The canvas looked great, but I noticed some of the 1/4" staples I had used had pulled out. I had just gotten some 5/16" staples so replaced all the old staples, retightening as needed (I don't think any tightening was needed to be honest). I sanded the canvas down to remove the high points and hosed it down to clean the dust off and left it to dry. The canvas still looked great. This morning the canoe was completely dry - and still looked great. So slapped on a marine topside primer (a Totalboat product). This took maybe 20 minutes with a roller. By the time I was done I had wrinkles all over the canvas. I suspect/hope these wrinkles will disappear as the canvas dries - I'll post a comment tomorrow. What I'm curious about is why the wrinkles appeared. Clearly the canvas is expanding due to the paint. I assume it's the solvents in the primer that cause the canvas to expand. But is this a surface affect? or are the solvents getting inside the canvas & mud and causing it to swell? I would think the dried mud would be impervious to solvents by now! In any case... any opinions out there?