by JonLee on Mon Oct 22, 2018 6:47 pm
My first suspicion is that you are not getting the right ratio of hardener-to-resin, in which case it will never harden. Epoxy resins harden require the ratio of resin and hardener to be fairly precise to cure properly. They must also be thoroughly mixed.
To test out this theory, you can mix up a small batch of epoxy (3-4 pumps) in a mixing cup and bring it inside the house to cure; this will remove the temperature part of the concern. Unless you live in an unheated castle. You can either leave it in the cup and apply some to a piece of spare plywood.
I have run into similar problems before. I will not admit to anything, but it is possible that in some cases the problem was working at too low of a temperature, in which case time and applying some heat eventually did the trick (don't ask about what is did for the strength of the bond, because answering that might cause me to admit to something). In some cases, and again I'm not admitting to anything, I might not have mixed my epoxy right. I won't say what I might have done to fix it, because I'm 93.6% certain that what I might or might not have done was not a good idea.