: Occasionally, when doing subsequent coats of epoxy, I'll get an
: area where the epoxy retreats, and leaves an uncovered dimple,
: or irregular shape. Got it tonight, coating a paddle. I'd like
: to figure out why, before beginning another boat.

: Tonight, and, I think in the past, I had done some 220 grit
: sanding, then wiped it down with denatured alcohol. It had sat
: at least an hour before I applied the epoxy. I'm using Maas
: slow, in a shop at about 70 degrees.

: 2nd question. When I had used System 3, the guide was to do
: subsequent coats within 72 hours, to avoid having to sand. Is
: that OK for Maas, too?

: Thanks

Your previous coats of epoxy under the new coat continue to cure and release
blush which rises through the new coats.

I find areas where epoxy will bead up on my third fill coat unless I scrub the
second coat surface down with water and a 3M scrub pad.

This is after epoxy glass wet-out, and two fill coats that
have been re-coated shortly after reaching green a tack free state.

Water is a solvent, and blush is water soluble.

Adding anything other than water increases your likelihood of surface contamination.

You can rely on luck, or get in the habit of a quick water scrub of any epoxy surface before
sanding or re-coating.

Rob

Even when I do everything right, there are still plenty of problems to fix.