I went in the studio in the week and had a chat with Martyn and I showed him my work that I had done. My mouth mould and my acrylic sample of shattered glass. He suggested I go back and work more on my mouthpiece because when I pour that into pewter it will be super thick and heavy. I will need to work on that to thin out the surface a bit more. We then spoke about the acrylic piece that would attach to the back. He said it looked good but the only issue was how I was going to attach it to the pewter without it taking away the aesthetic feel away.
He then suggested I work with glass or resin, as they could be sealed to the pewter with sealant. I then created some samples of crushed up bullseye glass with a layer of resin to incase it. The pictures of the process are below. I will need to let it dry before I can decide if the process/materials work well for the outcome that I want.