How To make a Shield boss, NON METAL

I was wondering what materials I could use to make a sealed boss, instead of using iron or steel. I came up with two ideas. First was polyester. So I made a simple mold to cast the polyester, then I wrapped it with a plastic bag so the polyester won't stick on it. It is the first time I'm using this, so it was really messy and the surface of the boss was really crappy. But I'm sure that someone with more experience can make a fine piece of it. I used heavy duty scissors to cut the polyester to avoid spreading that itchy wool all over my workshop. It is really bad, but it proved my point. Since the polyester boss is really hard. Then I started working on the second alternative, wood. I cutted a round piece and then before I started freehanding it on shape, I attached a plank on it so if anything went wrong my hands will be far away from the banjo. Then I used a belt sander to give it the final shape. In order to make enough space for the hand, you will need to carve a gap on it, as I did on Skalager's oombo. So, that was it. I hope you enjoyed it. Thanks for watching and bye bye.