a couple of rifles that had originally were repaired with what I believe was Acraglas. Time does not seem to be friendly to that formula. Acraglas seems to get 'brittle' over time.
All epoxies will be brittle if they are not mixed in the proper ratios. The rule of thumb is that the less catalyst you use, the more flexible the joint will be when it cures. Hotter batches cure faster, get harder, and will be mor 6e brittle as they age. Cooler batches may take a long time to reach full bond strength, but will generally be better in the long run.
So I switched to a marine epoxy, as those formulas are designed to deal with hull flex and movement...
Good working time and easily thinned by heating the stock with a lamp before applying the epoxy.
Warming the stock is a double edged sword. It will thin the material and allow better penetration and wicking, but it also accelerates the cure and can lead to the brittleness problem down the road. There are various grades of epoxy, with wide variations in quality, but all generally behave in the same way with heat and cure ratios. If you really need to thin epoxy and want to avoid heat, thin the epoxy with xylene/xylol and be prepared to clean off any squeeze-out immediately.
