Paintball tank unthreading in fridge

[Wheelman]

I have a paintball tank attached to a mini regulator and the original plan was to put it in the fridge with the keg to force carb and serve. Twice now I've (almost) emptied the tank because of a leak where the tank screws into the regulator. The first time it totally emptied, and I was surprised to find the tank very loosly attached to the regulator - so I screwed in the second tank much tighter. After 3 days in the fridge, I saw the carb pressure was down to 5psi instead of the expected 24psi. Once again, the tank had loosened off the regulator.

Any idea what's causing this, and how to prevent it from happening again?

 

[IslandLizard]

That does sound like a weird phenomenon.
Vibrations or temp changes perhaps?

Do you have any teflon tape on the threads? How tight can you screw it down, can that be the issue?

Why not buy a dedicated CO2 tank and regulator? Probably saves tons of money on fills alone. Paintball tank places gouge on refills. They charge by the oz (!!!) not pound! What is it 20 oz for $6?

 

[Wheelman]

No vibration - there is the temp change from room temp to fridge temp, but having it be fine for 2 days to start leaking on the 3rd is weird. I haven't put teflon tape on the paintball tank - didn't think it would be necessary, but sounds like a good next step.

Reason for the smaller tank is space and quantity - I'm a 1 gallon brewer with 1.75gal kegs, and don't have room for a full setup. I share the fridge in the kitchen and still need room for the milk

 

[IslandLizard]

How are you tightening the regulator onto the tank? Hand tightening?

There should be a rubber washer inside the regulator connection that makes the seal, as it compresses a bit. Maybe it needs to be a little tighter? That washer also puts some counter force on the threads, helping them to stay put. A few turns of teflon tape may help to keep it better together, preventing it from unscrewing. Or not.

You can weigh the tank/regulator assembly periodically to see what the usage stats are. If there's a leak, you may notice before it's too late.
But 20 oz is not a lot of gas to go with. I've lost 10# of CO2 in half a day due to a loose connection I had forgotten to tighten with a wrench.

If that's your setup, I'd consider getting a regular, larger CO2 tank (e.g., 20-50#) with a diptube inside, so you can refill your own paintball tanks.

There are ways to keep the CO2 tank + regulator outside the fridge and have a vinyl gas hose going inside. You do need to drill a hole in the fridge in a safe place where there are no pipes and stuff.

 

[Wheelman]

I haven't broken out the wrenches yet, but will definitely this time - Was concerned about the threads on the regulator side and overtightening, so left the tools in the box and hand tightened.

 

[Wheelman]

Hmmm. So I used teflon tape and the wrenches on this CO2 tank, and it's been good serving a keg, transferring from FV to SV after cold crash (all with the tank just hooked up for use), but started carbing (with the tank in the fridge), and in 24 hours lost 1lb of CO2 into a 1.75g keg holding 5L of beer. I'm guessing a slight leak in the keg, or a temperature related leak on my CO2 tank/reg/ball valve assembly.

 

[IslandLizard]

Hmmm. So I used teflon tape and the wrenches on this CO2 tank, and it's been good serving a keg, transferring from FV to SV after cold crash (all with the tank just hooked up for use), but started carbing (with the tank in the fridge), and in 24 hours lost 1lb of CO2 into a 1.75g keg holding 5L of beer. I'm guessing a slight leak in the keg, or a temperature related leak on my CO2 tank/reg/ball valve assembly.

Is that mini regulator working properly? If that's not leaking internally, chances are it's a leaky keg, and is very common. Lid seals are the usual culprit, but it can be the (external) post o-rings or the internal diptube o-rings too. Do you tighten the posts well down with a wrench? You should. Make sure there are clamps on all fittings. Just a barb inside a gas hose is not secure.

The easiest way to check for keg leaks is to submerge the keg with the gas hose attached into a tub or sink with water. A lot easier to do with a 1.75 gallon keg than a 5 gallon one. Look for bubbles, also jiggle/move the QD around a bit.

Most of us 'set' the lid o-ring with 30 psi, during purging the headspace, before lowering the pressure.

Spray the lid groove with some Starsan. With about 8 psi on the keg loosen the bail. Push down on an edge of the lid and it should go down about 1/8-1/4". Go around that way and check for leaks (bubbles). You should feel resistance and see no bubbles. Probably wear workers gloves, the edges can be burred and sharp. I smoothed most of my kegs' lid edges with a Dremel.

Oh, and use keg lube on all o-rings, quite liberally!