This armor piece is worn to protect the thighs. The right side is tire tread, and the left side is aluminum diamond plate. The metal is on the left as that side is more likely to be hit.
Working with tire tread is very difficult. It is almost impossible to cut, with the thick rubber and the numerous steel radials. Then once you do cut it, all those radials become sharp needles; not a good thing to have on your skin. But, a sawz-all with the correct kind of blade will cut it, and you may also need a large vice to hold it when you cut.
We had a fire truck get rear ended by a delivery truck, and they replaced certain parts of it that were damaged. I managed to get a hold of the parts they were going to throw out; namely a large section of aluminum diamond plate. My sawz-all cuts through it easily, and while I can't weld it, I can shape it and bolt pieces together.
So I got the two armor pieces to the right size and bolted them to elastic straps and a sturdy belt.