: Some theories... 1) as mentioned above I put the varying coats on way too
: soon. 2) the pattern of bubbles 'happened' to correspond to the part of
: the boat that was exposed to the sun through the garage window for a part
: of the day (grasping at straws here). 3) I 'think' that area of the boat
: also got a somewhat thicker application of epoxy on the fill coats. 4) I'm
: not 'positive' I mixed the epoxy well on all the coats. I remember
: thinking as I was about to put on one of the fill coats "Gee I didn't
: mix that enough... I wonder if I mixed the other batches well
: enough".

I'm using a different epoxy, but the manual does recommend applying the materials during the warmest part of the day, so that curing will occur as temps drop. If you do the reverse, expanding air could cause bubbles to form. This would be in line with your #2 correlation.

I can't believe the size of the bubbles you described! Mine are so tiny (and caused by something other than warming temps, because most of the treated areas turned out fairly bubble-free...I think. I won't trust it till a couple more days have passed.

Good luck, fellow newbie!