All epoxies work well it's just some are less tolerant about inconsistencies in the ratio of hardener to epoxy base. Heat is your friend in this situation - if you're in a warm environment and can leave it outside in the direct sunlight for a couple of days - if it IS going to finish cure, that should do it. Another option is to make a temporary cure box or "oven" of sorts. The quickest way is to go by a the storage or moving company and buy one the big stand-up "wardrobe" carboard boxes that are abour 4-ft high & have a small bar across the top for clothes hangers. You can get them at Lowes but they're about $20. Anyway, hang your stock inside the box and and cut a round hole just large enough that it will firmly hold a hairdryer nozzle, down near the bottom of the side that's furthest away from the stock. Start it out on high for about 5-10 minutes, then drop it down to low and let the sucker run but take the time to get an idea that you have the temp under control - it would surprise you how hot that thing will get = you can cut a flapper at the top that you can keep adjusting to regulate the heat - running it in the garage, back porch, etc. would be better than in the house or shop. You want that stock to get almost too hot to comfortably hold in your hand, but not so hot as to melt paint, epoxy or the stock. Also remember that when you take it out to check, you have to let it cool first to really check the cure - that's why I would let it run for several hours since the cool down will take at least an hour or so.
In the winter if I'm doing stock work, I typically have to use artificial heat like this to get good prompt epoxy cure. If this doesn't do it, nothing will and you'll need to dig it out the best you can and start over. Typically the thicker areas cure best and thin or 'skim' areas are more problematic. Hope this helps.
