Experience refilling argon or 75/25 cylinders yourself?

   / Experience refilling argon or 75/25 cylinders yourself? #1  

Sodo

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I was thinking about buying a 20 cu-ft cylinder (about $80) for portability. Then whenever I bring home a full 80, I refill (or top off) the 20 first while the 80 has full pressure. That way I always have a travel cylinder and a spare.

For Argon, filling the 80cf costs $81 and filling a 20cf costs $36 so it makes $$ sense to top off the 20 at home, then I can ensure that the 20 has a good load in it.

I have been refilling the little propane cylinders and understand the liquid vs gas issues. It seems like monitoring the weight is important but this is a guess.

Anyone willing to offer direct experience and details pertaining to this?
 
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   / Experience refilling argon or 75/25 cylinders yourself? #2  
Haven't tried that, but as expensive as CGA-580 fittings are it might take a while to see a ROI on it.

If I were to do that, I'd use two CGA males, a HIGH PRESSURE HOSE between them, then crack the low pressure (receiver) tank first, then the big tank. Then close both valves, and CAREFULLY crack one of the CGA fittings to bleed the approximately 2000 PSI gas out of the hose... Steve

These gases aren't liquefied, but their pressures are quite a bit higher than propane.
 
   / Experience refilling argon or 75/25 cylinders yourself?
  • Thread Starter
#3  
I have a broken CO2 regulator (for the fitting to attach to the tank).

To equalize gas pressure is just "easy". Understood about carefully cracking the fittings at the end (especially if there's liquid :shocked: ). Main question is: does liquid need to transfer to get a full load of "20 cu-ft of gas" in a 20 cf cylinder? Can that be that done by up-turning the donor cylinder?
 
   / Experience refilling argon or 75/25 cylinders yourself? #4  
No, these gases aren't liquefied like Propane, but they ARE at much higher pressure - like 2200 psi vs. maybe 200. That's why I mentioned the high pressure hose... Steve
 
   / Experience refilling argon or 75/25 cylinders yourself? #5  
Oh, and you will NEVER get a "full load", since you're removing gas from a (full) 80 cf cylinder to the smaller one - the pressures will EQUALIZE, so they can never be as high as a full one. Pressure in the smaller tank should be about 80%, or around 1700 psi if the big tank is at full pressure before you transfer... Steve
 
   / Experience refilling argon or 75/25 cylinders yourself?
  • Thread Starter
#6  
Oh, and you will NEVER get a "full load"?. 80% etc

If I could get 100% I'd be working on my business plan not just saving $30 :laughing: I haven't done anything on the fittings or hoses yet. Understand 2200psi pressure thats what the tank gauge says. Thx for the interest Steve. How do you KNOW that it's not necessary to transfer liquid to get an "80%" load?
 
   / Experience refilling argon or 75/25 cylinders yourself? #7  
If I could get 100% I'd be working on my business plan not just saving $30 :laughing: I haven't done anything on the fittings or hoses yet. Understand 2200psi pressure thats what the tank gauge says. Thx for the interest Steve. How do you KNOW that it's not necessary to transfer liquid to get an "80%" load?
Where are you getting liquid co2. The cylinders are compressed gas. Are you thinking it is liquid because when CO2 is discharged it creates ice crystals that look like liquid. There is no liquid in the high pressure cylinders.
 
   / Experience refilling argon or 75/25 cylinders yourself? #8  
I mentioned earlier - inert gases are NEVER sold in liquid form, except in REALLY large tanks AFAIK - all the normal welding gases are that way, except that acetylene is stored with acetone included in the tank, and possibly a couple other FUEL gases - but the inert gases such as argon, co2, helium, nitrogen, etc, are always in GAS form in portable sizes. You can get liquid oxygen, not sure who is allowed to buy it, maybe only industrial - we used to use it in the weld shop where I worked up til last year, it was manifolded to several work stations... Steve

Hey Gary, good point about the freezing - guess I was typing when you posted...
 
   / Experience refilling argon or 75/25 cylinders yourself?
  • Thread Starter
#9  
CO2 certainly goes to liquid at some pressure. Gary, Steve do you know for a fact that CO2 at 2200psi in a welding cylinder does not have some liquid at the bottom? In other words, of you have 80cf of CO2 in an 80cf cylinder, is there some liquid at the bottom?.

Also interested in Argon and the 75/25 mix. Somebody on this forum knows this for a fact.

:thumbsup:If it's not liquid,,,, then my plan gets simpler. :thumbsup:
 
   / Experience refilling argon or 75/25 cylinders yourself? #10  
They make booster pumps in various sizes
That would allow you to boost the preesure in the smaller tank.
Some of the paintball guys I know has one the one they had was a air driven and they had a 7.5 hp 2 stage compressor to run it. This device connects 2 tanks and transfers gas one from one tank to the other and allows you to increase the pressure. These guys were taking 2000 psi air tanks and boosting to between 3000 - 4000 psi. None of them are cheap think several hundred to thousands It would be cheaper 2 have a coupleOf cylinders to exchange so you a. Just equalizing pressure between the two tanks would not make sense because you would never have a full small tank. If an 80 cf tank started full at 2000 psi and you had an empty 20 cf tank you could only fill the small tank to 1600 psi. If you drained the 20 again and 80 cf tank was still a 1600. Next time you connected tanks they would both be at 1280 psi.


http://www.nuvair.com/booster.shtml

http://www.ebay.com/bhp/gas-booster-pump
 
 
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