I'd wait and sand at 4 hours. When I've tried to push it, I have gotten some sags. Sanding is not bad with the foam sanding blocks. You can do a whole hull in about 10 minutes, with another 10 or less to vacuum then wipe it down with a tack cloth. I like the satin finish too.

: When I initially finished my kayak a couple years ago, I was burnt out and
: couldn't face using real varnish and having to wait a day between coats
: and then sand, and then clean up and re-varnish, sand again, etc., so I
: sprayed the bugger with several coats of Minwax Spar Polyurethane clear
: satin and got out paddling.

: Now, I want to brush on several coats of the same poly, but I was under the
: assumption that I could re-coat each hour or two without sanding as I was
: able to do with the spray.

: Upon reading the label, it says to wait 4 hours between coats and then sand
: with 220 grit before applying the next coat.

: What I'm wondering is, if I wait only, say, 2 hours between coats could I
: re-coat without sanding and get a good chemical bond, like we do with
: epoxy that is re-coated within a short time period?

: If the answer is no, you have to sand first, then should I use wet sandpaper
: at 220 grit? Thanks for your help.