I apologize if this has been addressed elsewhere, and if so if someone could direct me to the appropriate location on the forum I'd appreciate it.

I have been looking into making a cast bondo/fiberglass helmets and I have no real idea how to start or the best methods. I have quite a supply of RTV silicone but with experience using it (in automotive work) I don't quite understand how it is used (It may be different RTV than what most use). I have been working on an Iron Man helmet and using various methods. I first pepped one and coated with a resin, which I did not mix well and had to dispose of. I then pepped another, and coated with an epoxy used for industrial concrete work, with actually was not very impact resistant (shattered). To reinforce it I coated with hot glue. It looks REALLY runny, but I wanted to see if I could build a rough model and if my scale was good. I then attempted to use 20 g steel, and I only completed the face place (too difficult for me to get the little details). I then found a better pep model and made one out of paper. Afterwards a discovered that Wally world sells cardstock and re-pepped. This is where I am currently at. I realize I will need to resin and bondo the pep model first, but I'm trying to think forward with the molding/casting. Any input?