I have always used the microwave and pyrex cups. I do not use a thermometer, I just know when it is ready. About how much do those syringes cost? I saw some at the tractor supply and co op but did not look at the price. I guess I would not have to suck up too much in it to just do a few molds part way, that way if it melted through I would not lose plastic much and would not get burned.