# CO2 Fitting O-Ring Size



## Steve001 (Feb 26, 2011)

Way back when, I purchased a 20 lb co2 tank there was an o-ring seated within the face of the fitting coming from the tank. I had this tank for many years, but recently I has to switch to a new supplier of co2. I had to trade my old tank for a new 20 lb tank which did not come with this o-ring. I've looked at Home Depot and Lowes to find one but have not found one of the right size. If any one knows what size this o-ring is let me know please.


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## Hoppy (Dec 24, 2005)

You can always just use a nylon sealing washer instead of the O-ring. I did that with my 5 pound tank, which also had the groove.


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## Steve001 (Feb 26, 2011)

Hoppy said:


> You can always just use a nylon sealing washer instead of the O-ring. I did that with my 5 pound tank, which also had the groove.


Thanks. Actually the original tank had both. I do have the washer. I'd just like the o-ring also.


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## lipadj46 (Apr 6, 2011)

Buy a perma-seal it is an o'ring mounted on a brass ring that screws in the tank


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## Steve001 (Feb 26, 2011)

Perma-seal thanks


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## Ahura-sama (Dec 7, 2009)

According to the owner of jandrwelding, you better off going w/ the nylon seal. The rubber o-ring get harden over time from Co2 and could screw up your regulator.


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## kevmo911 (Sep 24, 2010)

I've never had a problem using nylon seals, and they're dirt cheap (if not free from wherever you get your cylinder refilled or swapped).

This probably doesn't apply to you, but you can't use a permaseal with a Milwaukee regulator. I found out the hard way (though I've since seen warnings all over the place) and it cracked the odd-shaped fitting on the end of the regulator.


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## Hoppy (Dec 24, 2005)

The permaseal only works if both faces that it seals against are flat - no grooves. I wasn't able to use one either. But one nylon washer lasted me over a year, through about 3-4 CO2 refills.


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## whenjenn (Jan 12, 2016)

For me the nylon washer did not stop the leaks and is not needed for my reg. I had to replace the o ring that looked like a small rubber bank that fits inside the grove where the reg attached to the tank, once replaced it stopped the leaking from the nipple area of the reg. Don't ask Aquatek they won't tell you the size or the o ring so you will have to buy from them. Searched the internet for the answer with no luck so i wanted to share what I have learned, perhaps it will help someone else.
Go to your local mom and pop hardware store. They usually have a big box of different sizes. Take the reg if you can. My local store found one that fit although a little thicker than aquatek. Size for me was 3/8 x 9/16 x 3/32 o ring. Think it cost me 93 cents and no charge for the custom fit by my helpful local hardware staff. Stopped my leak and didn't have to pay double that aquatek charges, uhh if only I had bought a better reg. Live and learn. And yes oil it with a petroleum based product to extend the life and even thought its a little thicker than Aquatek the replacement will probably last longer. No leaks in mine getting the reg to give a consistent bubble count is another story for another question. Hope this helps.


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