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Filling small argon bottle from large?

N

neilho

Titanium
Joined
Mar 23, 2006
Location
Vershire, Vermont
Yeah, I know, sounds dangerous, hi pressure and all that, but here's my problem.

I maintain a 250 cu ft leased Argon bottle for my TIG welder. I also make vinegar and hard cider, both often stored in containers that aren't full. The best way to keep the liquid from oxidizing is to pump in enough argon to form a layer above the liquid that displaces the oxygen. CO2 could work, but I don't want carbonated vinegar.

All well and good to use argon from the large cylinder for the vinegar, but the weld shop and the vinegar dungeon are 100 yards and a flight of stairs apart and I don't feel like lugging it around.

So what I'd like to do is buy an 80 or 125 cu ft cylinder (anything easily carried), fill it from the 250cu ft bottle and lug the small one out to the vinegar.

Offhand, it seems that a stem and gland nut, from regulators, in each cylinder, connected to each other by a suitably rated union or a threaded connector should be a safe way to fill the small cylinder. I'm aware that the first filling of the small cylinder might include some air, but that's OK. The argon will displace the air in the vinegar container.

If anyone has ever done this, I'd like to hear how you did it. Or if you have a better idea than mine.
 
You just want a very small amount of argon, and only slightly above Atmospheric pressure ?

why not fill an inner tube (maybe even a wheelbarrow tube will work).

Minimal pressure, and when it goes flat, you can still squeeze some more out of it, into your vinegar.

Seems like you would use 99% of what you inflated it with.
 
neilho said:
Yeah, I know, sounds dangerous, hi pressure and all that, but here's my problem.

I maintain a 250 cu ft leased Argon bottle for my TIG welder. I also make vinegar and hard cider, both often stored in containers that aren't full. The best way to keep the liquid from oxidizing is to pump in enough argon to form a layer above the liquid that displaces the oxygen. CO2 could work, but I don't want carbonated vinegar.

All well and good to use argon from the large cylinder for the vinegar, but the weld shop and the vinegar dungeon are 100 yards and a flight of stairs apart and I don't feel like lugging it around.

So what I'd like to do is buy an 80 or 125 cu ft cylinder (anything easily carried), fill it from the 250cu ft bottle and lug the small one out to the vinegar.

Offhand, it seems that a stem and gland nut, from regulators, in each cylinder, connected to each other by a suitably rated union or a threaded connector should be a safe way to fill the small cylinder. I'm aware that the first filling of the small cylinder might include some air, but that's OK. The argon will displace the air in the vinegar container.

If anyone has ever done this, I'd like to hear how you did it. Or if you have a better idea than mine.
Click to expand...

Nothing to it, just get a piece of high pressure hose and put the proper fittings on it, connect the 2 bottles, open the valves, when you can't hear the gas flowing you are done. How much pressure do you want in the small one? If you connect a 2400 psi "T" argon to a empty small one your going to end up with about 900 in each cylinder. hook another new one up and you will end up with about 2000-2100 psi in each cylinder. I have done it 100s of times.
 
Tire inner tube will have a bad smell.
Shop Air Guns and Accessories | Pyramyd Air is a website that has a lot of stuff you can cobble together to get what you want. Also google airtanksforsale. I have a small carbon fiber tank that I charge to about 3000 psi for filling my tires at a track day. Tank is rated for 4500 psi and I do have 5000 psi Nitrogen cylinders for some of my air rifles. I have the quick connect fittings on a 6000 psi hose, fittings just like the ones in your shop, but very small. All plastic hose is maybe 3/16 OD? Or less. But the tank does get slightly warm when filled. I only need to charge it once a year. CF tanks are not cheap but all you need is a small one.
Pay a lot of attention to pressure ratings of the parts you are connecting together. Darwin incidents happen very quickly at high pressure.
 
Thanks for the replies.

I like Doug's idea, just because it's cheap and ingenious, but as Scruffy pointed out, it'll stink.

The air gun/paint ball fittings and tanks seem quality but a different system than my tank and spendier than Moonlight's solution. The spare/junk regulators box yielded a couple CGA 580 bottle fittings, the hose box gave up an unused hydraulic hose and the threaded connectors I may have to buy.

Even though hydrotested bottles are available on eBay for $150 or so, now I'm wondering if there's something usable in that stash of bottles from the fire dept. :)
 
neilho said:
Thanks for the replies.

I like Doug's idea, just because it's cheap and ingenious, but as Scruffy pointed out, it'll stink.

The air gun/paint ball fittings and tanks seem quality but a different system than my tank and spendier than Moonlight's solution. The spare/junk regulators box yielded a couple CGA 580 bottle fittings, the hose box gave up an unused hydraulic hose and the threaded connectors I may have to buy.

Even though hydrotested bottles are available on eBay for $150 or so, now I'm wondering if there's something usable in that stash of bottles from the fire dept. :)
Click to expand...

If you want to do it almost by the book the hydraulic hose is not necessarily rated for pressurized GAS.
 
neilho said:
Can I hire you to do that? Amish prices, of course. :D



Good point. Having second thoughts about smell in that hose, too.
Click to expand...

You take out the Schrader valve first....:D

Your telling me at the kitchen sink you can't get a small amount of dishworshing
soap down the filler neck ?

and some water from the tap ?

Fill it up with air, put the Schrader back in (or just the cap) and slosh it all around to get every internal surface covered.

Back to the kitchen sink, drain & rinse.
 
Yeah, I've a few Schrader valves in my life.:) Wash with soap and water, rinse 20 times, don't think that'll get the smell completely out, unfortunately. It's the way the rubber is. Good idea, though.

Could be that something like a water pressure tank with peroxide cured EPDM bladder would work, but I'd like a bit more than a week's supply at a time for the basement.
 
About 35 years ago, I cut up a car inner tube for some long-forgotten purpose, and I remember the rubber smell did not go away, even after several sessions of soaking and scrubbing.
 
I fill nitrous oxide bottles. We just use standard fittings and a length of teflon lined braided hose. That should not transfer any smell to the argon.
If you chill the small bottle and warm the big one you'll get more in it, but you need to watch out for overpressure when it returns to room temp. For N20 we go by weight, argon doesn't transfer as liquid so I'm not sure how close the weight correlates to pressure..
 
1/4" npt ball valve with standard nipples on each end, large party balloons from
the party store.....
 
Found a line for $32 at Welding supply.com that'll connect to the CGA nuts and nipples I already have. The key search word was "transfilling". For storage, I'll prob buy a used 80lb cylinder off eBay, used argon/oxygen cylinders being scarce in Vermont. Anyone in New England have one for sale?

Still thinking of a CO2 fire extinguisher bottle (I have several), but they're only good for 800psi and use a totally different valve/thread. I can dick around with that for a day and have an unsalable kluged up rig or spend the $230 and be done with it. (And get my partner to pay half). Hmmm, what to do? :D
 
dalmatiangirl61 said:
Get a small medical oxygen bottle, smallest I've seen is about 12" long 3 to 4" dia, standard size ones are about 2 ft long 4" dia, some even come on a little cart. Scrapyard usually has a few lying around.
Click to expand...

Use extreme caution when transfilling any cylinder that is not design rated for pressure that would exceed the maximum transfill pressure. Never use scrap yard cylinders for anything high pressure, there's generally a reason why they where scraped.
Filling a innertube is one thing but charging an unknown cylinder with a thousand plus pounds of pressure is flat dangerous.
When transfilling a high pressure cylinder into another cylinder then that cylinder should have a current hydro test.
 
Mud said:
I've seen used nitrogen cylinders on ebay for under $100. I think the CGA fitting is the same.
Click to expand...

Hadn't realized nitrogen bottles used the same valve (CGA580). Thought it was just Argon and Oxygen. Thanks.

This used bottle has a max pressure rating of 1000psi, which makes me a little leery, since the large bottle I'll be filling from is filled at 2640psi (T cylinder) and given the difference in bottle volumes, would be easy to over pressurize without a gauge.

'Spose I could just plumb a gauge into the transfill line. Prob not a bad idea anyway.

dana gear said:
Use extreme caution when transfilling any cylinder that is not design rated for pressure that would exceed the maximum transfill pressure. ... charging an unknown cylinder with a thousand plus pounds of pressure is flat dangerous.
When transfilling a high pressure cylinder into another cylinder then that cylinder should have a current hydro test.
Click to expand...

I do have it firmly in mind. Never hurts to have a reminder.
 
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