I'm still casting fine with urethane I opened about eight weeks ago. Sometimes the only way to decide is to try it both ways. You might get results you like well enough for your purposes with the cheap stuff. If you have family around, they will complain, though! I think polyester is usually a false economy.
i read someone used the resin (just the resin) to harden a papercraft helmet, i wonder if such can be used to cast something out of a mold??
hello, I am not as experienced with resin as the others here, but worked a little bit with all three kinds: polyurethane, epoxy and polyester. in my opinion, as many other stuff we are handling in our life these are all toxic, at least the hardener. its just a fact you should have in mind. so, to use them outdoors, or in a workshop with the windows wide open and also using an carbon filter mask is always a good idea. bud I dont do that all the time too, though. the fact something smells less, dosnt mean its less toxic
well for the question itself as I said, I m not really experienced, just can tell that polyester really heats up and cracks, but I know some that is special for casting and is much slower. there are many types of every stuff. epoxy gets warm too if it is a fast one I think just as polyurethane does. but, for casting I liked polyurethane the most, because its a little but more stabile because its a little bit elastic so it wont crack so easy. and the surface is much better with less bubbles. and its easier to work with because normaly its just one part hardener and one part resin. i would say the price difference is not too much.