Given your relaxed standards, could you use something like RF
gasketing to improve the seal over what you now have. Or maybe add a
tube that would run outside of the heated area and use a gas to
exclude the oxygen. Argon or nitrogen would be great if you had them
available. But methane would work as long as you made sure all the
gas that escapes burned. Easier if you used natural gas to do the
heating and to provide the atmosphere.

Dan


"Sheltech" wrote in message news:
Okeley Dokely, to answer a few replies at once,
This is for an annealing box with a flat lid that will screw on . I'm annealing copper sheets in an electric kiln.
Perfect seal isn't actually required because the customer isn't fussy about getting pristine copper
parts; in fact , torch-annealed was adequate. I mostly want to 'automate' the annealing.

Flexibility of the gasket material isn't actually necessary, I just sort of assumed that rigid materials wouldn't
be among the candidates. Copper might work if I used socket caps and cranked them, instead of common machine screws.
For that matter, if my box had a milled-flat flanged rim instead of the non-flat one it has and a thicker, flatter lid, I might
get by without a gasket at all, given the relaxed standards of the customer.

ps "pure gold" ..... if that was a bad idea it wouldn't be funny. good one.

thx
DS