My first thought was to make a resin piece that would just fit into the opening of the copper ear. My concerns were how to attach the ear and the eardrum to the strap which will fasten to the mask itself with snaps, and how to keep the weight down. A mask of this size can get heavy pretty fast, and be uncomfortable to wear. I was planning on bolting the eardrum through the ear and through the strap, but this presented the problem of hiding the bolt head on the front of the eardrum, and also on the bottom side of the leather strap where it could rub against the wearer’s skin.
After deciding that a resin piece would be too difficult to attach and too heavy, I considered a wire screen or other thin metal dome. Given that I don’t have many metalworking skills, I eventually opted for making the eardrum out of formed leather.
I knew I wanted the eardrum to be domed to give it a little class, so all I needed was a form over which I could shape the vegetable tanned leather. I looked around my shop for a suitable something—I was thinking of a bottle lid—to no avail. I thought perhaps a drawer pull would have the right shape to it if I could find one with the right diameter. Going to my local hardware store I quickly found just the knob I needed. The first picture shows the copper ear, the knob, and a piece of plywood ready for attaching the knob to.
I carefully measured the opening in the copper ear, and cut a hole the same size into a piece of ¼” acrylic plastic. I added a second piece of wood on top of the plywood to reduce the height of the knob, thus completing my forming jig, as shown in the third picture.
I then cut out a circular piece of oversized leather with the ventilation holes already cut, and soaked it in water to make it plastic. I laid the damp leather over the knob, and forced the acrylic piece down over the leather and knob, stretching the leather and conforming it smoothly to the knob. I held the forming jig together with two clamps as shown, and let the leather dry.