I made a few or so in the past. Was using 1 a little forcefully 1 time , hit it and don't remember exactly how, but it split and a chunk of the wedge shot back at me hitting my forehead pretty hard and fast. Stunned me a bit and I got a minor cut and knot on my head and quit on the home made wedges. It was made of seasoned black oak.
I usually have 1 good small wedge on me and 1 damaged already wedge or 2. When I can will get the damaged wedge in, I try to have it the closest 1 to the chain. I'll get bigger and better wedges from my truck if I fore see I will need them. They last me well enough at that. The small wedges I was finding at near $5 each, usually by the dozen which a dozen have been lasting me a few years or better. The bigger wedges I don't need often and seldom need to buy. Bought some of them in lots on ebay used in the past, picked some up at auctions or flea markets and something like 4 to 6 from Baileys. I've had some aluminum also which I like. More expensive but most mine came second hand in excellent shape. Are more durable then plastic. Used to use steel sometimes, mainly after starting the procedure with a soft wedge. at 1 time used to carry an little more then flat wedged shape steel schim which worked very well when the cut was shut from pressure and I wanted to wedge it the other direction.