For a heater I used two 1200W patio heaters, which I put inside a wooden box, lined with tin foil. At the moment I have to plug the two heaters into two separate circuits as to not overload the breaker; eventually I'll get a proper setup going, but for now, everything works like a charm.
You can check out my video of my Sith Acolyte mask build, where you can see my vacuum forming setup in action here:
[media=youtube]d5G2vhpILYg[/media]

