Doing a bit of a thread necro here, but I figure I can't be the only person who who's done this. I recently lost the washer for my false bottom and I ended up replacing it with these http://www.mcmaster.com/nav/enter.asp?partnum=91525A145
They're 316 stainless and they seem to fit like a glove, I bought a 10 pack and they came out to a little less than a dollar a pop shipped.