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RTV diaphragm

Posted: Wed Apr 18, 2012 11:38 am
by Bumpkin
Has anyone here made their own custom diaphragm by layering fabric and rtv or plain silicone? It'd be nice to be able to make the exact shape and weave-strength orientation you want. You could even cast in some metallic portions. Any tips?

Re: RTV diaphragm

Posted: Thu Apr 19, 2012 12:11 pm
by Junkie
I haven't tried bonding it to a cloth backing, but I made an RTV diaphragm for one of my Stirling generator that worked reasonably well.
I used a balloon stretched over a tin can, I forced some of the air out to give the balloon a slight satellite dish shape. Next I spread a
thin layer of RTV over the balloon. Once the RTV was set, I could peel away the balloon, leaving just the RTV diaphragm.

You can see a video of it here : [youtube]http://www.youtube.com/watch?v=rdlDP2Udg2g[/youtube]

Re: RTV diaphragm

Posted: Thu Apr 19, 2012 1:13 pm
by Bumpkin
Thanks Junkie. Did you use anything between the balloon and the rtv? I would have thought they would bond tighter than that. Neat video, though it's been a half-hour and I can't get past 0:47. I almost never watch videos because I'm on dial-up and usually get more out of diagrams anyway, but I always like to see folks stretch the bounds of every-day materials.