This worked for me. I once had a coat of epoxy that did not cure, I mixed up a new batch paying attention to mix ratios and put it on over the old uncured. Everything then cured okay, just took a couple of days instead of a couple of hours. Seems that once you get the chemical reaction started, it tends to continue into the improperly mixed part. Heat (not enough to make it bubble, just hot to the touch) speeded things up.