I kept putting on fill coats of resin with a brush and as spidey said, I kept picking out brush hairs. I tried the foam brush, but it would flake off small bits of foam. Anyway, every coat I'd put on would run or sag. I'd scrape it off, sand the whole thing down and then put on another coat that would run, sag, etc.

After getting tired of this I decided to try something else. I sanded down an area of the kayak so there were no runs, sags, or low spots. I don't want the kayak to look sanded the entire time I'm working on it until I get it varnished, so I mixed up a small batch of epoxy and rubbed it on with a clean cloth. I used a terry cloth, but a plain cotton cloth should work better. I was able to put on a REAL THIN coat without the runs etc. I will actually have to put on a couple of these coats if I want to build it up.

My idea is this, why not build up 3 coats with a brush, then clean off any unavoidable runs and sand it down. Put on any future filling with a cloth and avoid having to sand it all down again. At least it would only be light sanding.

Has anyone else tried this and if so how did it work for you?