ptfe o-ring

[Withered Worm]

Can anyone think of a reason why it would be a bad idea to use small diameter ptfe/teflon tubing, sold in American big box hardware stores, shaped into a hoop to make an O-ring for my beer keg still?
My boiler keg is a 15 gallon with a round hole cut at the crown of the keg that's about 10" in diameter which makes cleaning the keg easy, and its top with sankey fitting is made from a second keg and is of a roughly two inch larger diameter than the hole's diameter so overlaps the keg hole by about two inches all around. The sankey crown is pressed down with a angle iron and bolts arrangement that hooks under the keg's rim. I've been using flour paste to seal it so far, which works, but would like to upgrade to a gasket for the sake of convenience.
Tom

[BoomTown]

Tom,

I just took a piece of heavy paper (card board but not corrigated) and made myself a paper ring. Then I wrapped it with PTFE tape, two layers thick, and use it. It works great. It's simple, cheap, and it works. Try it before you spend a lot of money.

[S-Cackalacky]

You should be able to make a suitable gasket with cardboard and ptfe tape. I use one to seal an inverted mixing bowl to a stock pot boiler - works great. There's a thread here on the forums that demonstrates how to make one - search for "cardboard/ptfe gasket". You can get a suitable piece of cardboard from a picture frame shop - the stuff called matte board.

Posted while BoomTown was posting. Great minds think alike.

[bearriver]

I don't know what you are talking about, but if it is PTFE, why not? I would wrap it in PTFE tape to keep it together.

I have used compressible PTFE valve stem packing wrapped in PTFE tape with success in making a seal.

Edit: posted with the others, who gave great advice.

[yakattack]

Can anyone think of a reason why it would be a bad idea to use small diameter ptfe/teflon tubing, sold in American big box hardware stores, shaped into a hoop to make an O-ring for my beer keg still?
My boiler keg is a 15 gallon with a round hole cut at the crown of the keg that's about 10" in diameter which makes cleaning the keg easy, and its top with sankey fitting is made from a second keg and is of a roughly two inch larger diameter than the hole's diameter so overlaps the keg hole by about two inches all around. The sankey crown is pressed down with a angle iron and bolts arrangement that hooks under the keg's rim. I've been using flour paste to seal it so far, which works, but would like to upgrade to a gasket for the sake of convenience.
Tom

Providing it is actually ptfe (and you can verify it) then there is no reason not to but I've yet to see ptfe tubing in any store. Reason being is its bloody expensive. 100 ft of 1/4 id will run you 400 bucks or more. There are a few sites online to get it cheaper but in general is say make yourself an everlasting gasket. Cardboard and ptfe tape. Find good hardboard that's chem free. Alternately do a few wraps of the thick ptfe tape on both surfaces and that should be enough to seal it. (Its how I do my fittings. ) usually lasts a few runs or more.

Yak

[Withered Worm]

Providing it is actually ptfe (and you can verify it) then there is no reason not to but I've yet to see ptfe tubing in any store. Reason being is its bloody expensive.

You're right. I thought I had found an inexpensive source of ptfe tubing, but on closer examination it turned out to be something other than ptfe, and real ptfe tubing is bloody expensive, as you say.

Tom

[sltm1]

Solid PFTE doesn't compress so you'd have to mill both top and bottom surfaces perfectly flat along with both sides of the "O'" ring gasket. Then pray you don't accidentally mar any of those surfaces or you'd have to do at least one of them again.

[rad14701]

Another simple yet effective solution would be to wrap the keg top with PTFE tape... I have done multiple runs using a trimmed down pizza tray as a lid for my 30L stock pot, wrapped with several layers of PTFE tape... Just make sure there are no sharp edges...

[bearriver]

Solid PFTE doesn't compress so you'd have to mill both top and bottom surfaces perfectly flat along with both sides of the "O'" ring gasket. Then pray you don't accidentally mar any of those surfaces or you'd have to do at least one of them again.

With solid PTFE, yes. Pure PTFE can come in multiple forms. Some is hard like most plastics, some resembles the silicone used in brewing tubing, and some resembles stiff compressible string cheese. I got this PTFE gasket material from Inertex that stretches length wise but does not get thinner as it is stretched.

Anyways my point is that a few wraps around hard PTFE gasket with PTFE tape will do the trick when making a low pressure gasket. The tape will allow for imperfections.

This is a spare for one of my bulkhead drains, wrapped in PTFE. All of my hard PTFE tri clamp gaskets are wrapped in PTFE tape as well.

[BoomTown]

You should be able to make a suitable gasket with cardboard and ptfe tape. I use one to seal an inverted mixing bowl to a stock pot boiler - works great. There's a thread here on the forums that demonstrates how to make one - search for "cardboard/ptfe gasket". You can get a suitable piece of cardboard from a picture frame shop - the stuff called matte board.

Posted while BoomTown was posting. Great minds think alike.

Thanks S-Cackalacky, I feel like I just got a promotion..