Rubber membrane

[higgs10]

Hello everyone, I am currently building a displacer type stirling engine and have noticed on a few that i have seen on the internet have a rubber membrane on top of the displacer piston port. This is currently the last piece of the puzzle i need to collect before completing my engine so i was wondering if anyone knows where i can buy one of these rubber membranes or what i can find one in. Also i would appreciate any suggestions for things to use for this membrane as an alternative.

Thanks,
higgs

[higgs10]

Thanks for the reply. Yeah i basically just wanted the rubber membrane for looks but I'm giong to go with the piece of the glove. Thanks again I'll let you know how this thing turns out. It's my first one so im crossing my fingers.

Thanks,
higgs