Never had much luck with it on models. It's hard to work with, mixing or kneading the two pieces of material to a uniform consistency is difficult. And once you open the sealed packages, the left over material will get hard in a couple months and you'll end up throwing out the rest of the expensive stuff.
I think it is intended for more heavy-duty, large scale things. I fixed my wife's broken ceramic bird bath with it. It's like concrete when it cures.