By the end, I had this. The edgest could have been a little cleaner, but the wood got sanded while on the lathe as well down to 400ish grit. Nice and smooth
After the wood, I worked with a piece of metal and forged it on the english wheel. It began by hammering a circular piece of metal which was cut out of a sheet by the bandsaw. The circular metal was hammered with a plastic mallet against a tool I made with a curved top. This wood tool was placed in the vice during early forging. It was smoothed out later by the wheel.
As for the plastic, I took a plastic sheet and folded it into a cone shape. I then applied heat from a heat gun onto the meeting edges after cutting it out. I squeezed the hot gooey edges together using a set of rubber gloves. The finish left a textured fused edge, and ended up looking like a holster. After a few fails, I eventually got a water tight seal.