I am testting out viton gaskets for the vacuum chamber.
Viton gaskets are reusable replacements for single-use copper conflat gaskets.
The gaskets are rated down to 10e-8 torr, which is fine for now.
The smaller gaskets installed easily, but the large 8″ gaskets were impossible to install… they fell off the flange.
I called MDC and asked “what’s the trick?”
The trick is a little vacuum grease to retain the gasket!
I ordered APIEZON TYPE M vacuum grease from ebay, also rated down to 10e-8 torr.
I made 8 tiny dabs of vacuum grease:
And it worked!
After a few hours the chamber went as low as 5.5e-5 torr. Totally fine for now, but could be better.
I will continue to use them.