Some o-ring questions

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Green Flash IPA on tap
HBT Supporter
May 20, 2007
Reaction score
Southern Oregon
Hey all,

1. What material are the o-rings on cornies made of, EPDM?

2. Is this what most o-rings are made of?

3. Does anyone know a source of food-grade o-rings, specifically, I am looking for a corny lid o-ring with a larger cros-sectional diameter.

I just got my McMaster order the other day. Buna-N for dip tube and post. I think the lid seal is Buna-N too.
Buna-N is what most of us use. #109 for the diptube, #111 for the post seal, #417 for the lid. The cross section of any #4xx is 1/4". Why do you need a larger one? If you're having trouble getting a seal, try some keg lube.

(1) Dip Tube O-Rings
5/16" ID x 1/2"OD x 3/32" width
9452K172 BunaN #109

(2) Post O-Rings
7/16" ID x 5/8" OD x 3/32" width
9452K23 BunaN #111

(3) Lid O-Rings
3 1/2" ID x 4" OD x 1/4" width
9452K218 BunaN #417

(4) Double-Seal Viton Dip Tube O-Ring
(Same as 90025K12)
AS568A Dash Number 109

(5) Silicone Post O-Ring
7/16" ID x 5/8" OD x 3/32" width
9396K24 (Same as 9396K6)
AS568A Dash Number 111
Thanks for the replies,

I am having trouble because I have 1 Firestone keg that I got used with an aged, and cracked PRV. This particular PRV is two piece plastic, and threads together with a gasket through a 3/4" hole in the top of the lid. While the keg held pressure with the old valve, I did not want to use it with the cracks possibly harboring bacteria. I cannot find a replacement anywhere. I ordered a replacement lid, which was supposed to fit either corny, or Firestone, but simply will not seal on the firestone. I figured that an o-ring with a slightly larger cross-sectional diameter would probably be the ticket.

Does anyone have any ideas?

I don't weld stainless, and yes, the lip on the keg is in perfect condition.

Simple answer buna-N is good for anything beer!!!! Your safe t go to the hardware store and get whatever you need for o rings!!!! GO PACKERS!!!!!!!!!!!

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