It mixes quite easily, but is a bit more "runny" than I would prefer, although that makes it easier to get into crevices. A similar product that comes in sticks is Selleys Kneadit. You cut off the size you want and knead it to make a homogeneous grey paste which sticks very well and sets like stone in about 10 minutes. JBWeld is black/ dark grey and takes about a day to reach maximum hardness, which can be helpful when you're trying to get everything the way you want it before if "goes off".
Both resist heat and can be drilled and tapped and act as an ideal filler, especially the Kneadit.
The original epoxy, Araldite, has its merits, but I've found you have to be quite precise with your measurements or it doesn't set.
