I've used a heat gun to get very cold epoxy resin into a workable state. Don't know how hot it was, but the plastic bottle was a bit too warm for comfort. The resin didn't degrade with the heat, I used it on an undercarriage mounting plate with no problems regarding strength. I've tried to remember to take my water based glues and epoxy resins indoors for the winter, never do though. The epoxy seems to survive the cold, but the wood glue goes lumpy and sulks.