The epoxy has to be fully cured to sand. If it gums up the paper it's not cured enough. I'm using MAS slow, and it takes three days at 60 or above, longer if it's cooler. I just found, tonight, that 100 grit on the random orbital does a good job of smoothing the top coat up without cutting too fast. Paul is right; just enough to get the highs is all it takes.

> Paul- thanks for your reply.Ijust finished putting the third coat on both
> the kayak and canoe & it did seem to smooth out a little bit more.How
> long should I wait for sanding?Doing to boats at once was not as easy as I
> though!