Redditor shoeinthefastlane took great care in making a replica of House Lannister armor from Game of Thrones over the course of three weeks. And he also took great care in documenting the build by taking dozens of photos showing each step. He describes the materials used:
I used 6mm and 3mm Sintra for most of the parts, Apoxie Sculpt for details. Leather straps, buckles, gold rub-n-buff and paint for finishing. The Sintra was purchased by calling a sign shop and getting their supplier who delivered 2 4×8 sheets and were vastly cheaper than online. Heat gun, dremel and a knife were sufficient for tools. The Sintra is expanded PVC foam, fumes weren’t terrible, but the dust is very fine so a good respirator is recommended.