With the USComposites slow hardener...the 556/635 combination...I've never experienced any blush. During the same time when I used the RAKA I did have a little blush. Don't get me wrong...I like the RAKA...but it costs more...and I'm poor (I build kayaks). I did mention that I used the 1 to 1 USComposites for mixing up fillet goopie and that I didn't know if I would get anymore. Well...I'm out of it now...and I want some more. It is a little faster than the slow stuff. I have used Helmsman's Spar Varnish on one boat, Acrylic latex on another (a fishing kayak)...and I haven't varnished the current project yet. My little play boat was hung out in the patio for two years with just the saturation coat on it before I went back to work on it. The epoxy/fiberglass was in great shape with no white spots at all. I just sanded it a bit and started in with the fill coats. One other thing...almost all my sanding is with 80 grit...sometimes 100...sometimes 60 grit at the beginning. On most boats I put on what I call a utility finish...which is pretty good....but not what I would call heirloom quality. I'm going to do that someday. Two more things. I'm looking for a good UV protected water base urethane varnish to use on the boats. If my floor varnish had UV protection I'd use it...but it doesn't.