Are you using the IR color slide film?
Most BW IR, while expensive compared to regular BW film, is still less than $10 a roll.
You should look into digital IR. Many folks are doing it with just a filter added to their regular digital cameras.
I know that all advice goes against what I'm about to say, but I've loaded at least a half dozen rolls of Kodak and Konica IR into my camera with no changing bag in the direct, hot (95+) August sun, with only my body as shade, and never had a fogging problem. I don't encourage this kind of sloppy/lazy behavior, but so far I have not been punished by the IR gods for my insolence.