I am trying to make a halo brute cosplay with a rubber latex mask I understand the basic method of making the head mold but have no clue where to buy the materials for it.
Smooth On have been a trusted supplier of Latex, Silicone, and (casting) Foam for a very long time. They offer Trial Kits, have extensive tutorials and support, and can either ship directly to you or point you to a local affiliate.