View Full Version : Need Help! Vacuum Forming a Large Body Mold -- Help Please

03-22-2014, 09:40 PM
First, thanks for reading this.

I am working on building a car for the Shell Eco-marathon competition, and would like some help on the molds for the body. Currently, they are XPS with joint compound (drywall) to fill the low spots. The body will be out of approx. 60 thou clear polycarb *(Lexan) sheet. I have also built a 4'x8' vac table to accommodate these large molds. I have a few questions, I'll number them below for easy reference.

1) To coat the XPS molds with a smooth, hard finish, can urethane be used? Or a latex paint layer and then urethane? Or.... What is the best option in terms of smoothness, hardness, and workability?

2) If you have experience with polycarb or PETG, which do you recommend?

3) Should a release agent be used?

Thank you again, I'd be happy to post pictures if needed.