Building Body Kits From Scratch.

First off I apologize if this has been asked before. I already searched the forum and found nothing. Not too long down the timeline here, I will begin trying to get my hands on a pre-'55 Pick-up. I want to customize this truck in the muscle car fasion. I am trying to figure out how to build custom body parts from scratch. I have seen it done in different programs but lack the details such as materials and steps to take. I would prefer to know how Urethane parts are made as they are a bit more forgiving and less prone to cracking so, if anyone knows, how do I construct Urethane body parts (or fiberglass, be specific) from scratch? Thanks for your help.

I have had good luck using 1" thick nylon sheeting from our local plastic supplier. I just use a 4" hole saw on my drill. By using the round hole saw with center starter drill bit..the finished disk/spacer then has the center hole. The nylon won't split or crack and comes in different colors. I just purchase the "drops" or leftovers. I use the nylon for lift and still use the OEM rubber mounts on top.

Ed
Buffalo, NY

So how do you go about forming it to the shape you want...and get it to hold that shape when you are done.