First, all epoxies indicate the set-up time as to when it is set enough to be somewhat unchangeable. All require additional time to "cure."
A few tips for your note book! First, if you get too much hardener it will set up faster but be more brittle. More resin than specified, and it will set up slower and be rubbery; too much resin and it won't ever get real hard. Using a little too much semi-liquid color or stain will retard it as well, but it will finally set up. Using a heat gun or hair drier does work, does speed up the drying time and does make it get into crevices better, but it will make the epoxy a bit more brittle so use care here. Another tip that is critical; use the heat to warm up the part to release it from the epoxy. Use only enough heat to the part as you are pulling up on it for it to release and get the heat away immediately. I will warm up the brass and give it a couple seconds for it to translate, and it will usually release without distorting the epoxy.
The very best option for fast curing hold for any odd shaped part to be engraved is to use Bondo. Now that is the best I have found! ANd its a whole lot cheaper and you can still use heat to pop it lose!
Susie