Why the need for a seal? if its for pressure driven transfer i dont think stockpots can be modded that way, however if its only for a blow off tube or airlock then a simple wrap of poormans parafilm tape (ptfe) tight over the lid/pot jucntion should suffice, it works for the distillers
While I have not used it for this purpose myself, i have used it to seal the diy yeast test plates i made which maintained sterility with no microlife growth on the agar/malt medium after 12months @ room temp.. just a shame im so ham fisted and tear up the medium when attempting to streak them ;(
That's a really good suggestion and I can't quite believe I didn't think of it. I spent some time looking for large silicone gaskets and stock pots with lid clamps. Both do exist but I couldn't find an consumer retailer cheaper than the Italian one.
Oh well, I think the Italian one is on order now but if I want to get a second stainless FV in the future then I'll just bodge it with PTFE tape.