This video was the inspiration for our vacuum forming projects last year.
http://www.youtube.com/watch?v=hGBRi...eature=related
Polycarbonate absorbs moisture. To thermoform it you must heat it to drive out the moisture or the water will turn to steam and give you bubbles. Thermoforming plastic is very do-able for teams however you can get better strength and results with composite methods if you have the resources.