This is a VERY LOW cost way to make helmet casts, total cost: 15$.
Plaster of Paris, big jug: $5 hobby lobby
Plaster Cloth: Big Roll: 9$ hobby lobby
Im also looking for another cheap material I can make the casts out of, liquid plastic is wayy too expensive,
65-100$ for a big jug. If I find another cheap material to make casts ill post the instructions as well.
Plaster casts are good but extremely fragile, 4 layers or more are require to make it thick to make sure its stronger. to really make this helmet safe you would have to fiberglass the inside of the helmet and Bondo the outside.
LATER on if my casts come out good and everything is good I might sell a few base helmet casts on ebay, but this wont happen for a while.
i'm going to use Silicon rubber as the mold instead of plaster cloth next.
here is an instructional video on silicon molding: