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High Pressure welding bottles

Posted: Sun Mar 19, 2017 1:47 pm
by gunsmoke77802
The guys at work know I shoot compressed air guns and ask why I don't used 4500-6000psi nitrogen. You can buy/rent a bottle from the welding shops and regulated it down to what you need. It looks attractive. My scuba shop can't or won't go over 3000psi. It eliminates the hassle of the scuba tank. And really a welding tank cost about what a scuba does and you just exchange it when it needs refilling. You don't have to worry about retesting it.

Re: High Pressure welding bottles

Posted: Sun Mar 19, 2017 2:11 pm
by Rover
Air is mostly nitrogen anyway, so I say 'go for it!'

BTW You can do a search and find posts on the subject.

Re: High Pressure welding bottles

Posted: Sun Mar 19, 2017 3:36 pm
by Dr. Jim
For at least a decade the Calgary club has used dry nitrogen for airguns. Works just fine.

Re: High Pressure welding bottles

Posted: Sun Mar 19, 2017 3:50 pm
by DFWdude
gunsmoke77802 wrote:And really a welding tank cost about what a scuba does and you just exchange it when it needs refilling. You don't have to worry about retesting it.
No retesting because you don't own the tank. You lease it. Some people find really appealing deals, mostly those with ties (for discounts) within the welding industry. But others find that the initial lease down-payment, annual lease payment and refills/delivery charges are not economical. Buyer beware.

For the same money over 5 years, one can buy one of the new generation, lower priced compressors (Air Venturi and others) and refill your scuba tank at your leisure.

Re: High Pressure welding bottles

Posted: Sun Mar 19, 2017 5:16 pm
by TenMetrePeter
What do you pay for a Nitrogen refill? Air refill costs me about $3.

Re: High Pressure welding bottles

Posted: Sun Mar 19, 2017 6:59 pm
by jenrick
But others find that the initial lease down-payment, annual lease payment and refills/delivery charges are not economical. Buyer beware.

I have no clue where you're doing your tank rentals from, but that's not anything I've ever had to deal with.

The local welding supply places here do it one of two ways. The most cost efficient in the long run is to buy the tank up front (which for a big 300 cf tank runs between $250-$300 last time I looked), and the first fill is usually free (Nitrogen is cheap!). After that whenever you finish off your tank, just bring it in, and they'll swap you a fresh tank that's already filled. You never have to worry about testing or inspecting the tank as they take care of that on their end. If you ever decided you're done with the thank, they'll buy it off you for a good chunk of the original cost (as the tank you have is usually well within the service date). The other option is to rent a license on a tank (usually about $60-$100), and then it works the same as above. If you ever decide you don't need a tank anymore, you can't resell it you have to return it (they usually rebate you some money on it though). Usually a fill of Nitrogren will run you less then $30.

Beyond that a good regulator is all you need. I don't shoot a PCP so I have no clue how well or poorly it would work, but it wouldn't seem to be a major issue.

It would seem to be a good solution for a large club tank, as 300 cf at 4500 PSI is going to last for a while.

-Jenrick

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 3:08 am
by TenMetrePeter
When you use it for industrial purposes I guess you run it nearly flat. For shooting in needs refilling at 2800 PSI.
For me I pay to retest my Scuba tank for £45 every 5 years and £2 per six months for a refill. With N it would be £25 every 6 months for a refill at those $ prices, and ok no testing. Thats expensive for one shooter. Obviously you might make a financial case for N but when the variable cost goes up by a factor of 10 you wont get benefit from group usage. Let's be honest this only works out financially if you can "borrow" the company N cylinder.

Any paramdics out there, don't try it with oxygen.

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 5:17 am
by JamesH
Just remember that if you're using/storing it in an enclosed space you should have a low O2 alarm.

Its not very likely that a leak will displace all the O2 and asphyxiate everyone in the room but its possible, whereas with compressed air its not.

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 6:47 am
by 10M_Stan
For target airgun use, I use an 80 cu ft aluminum SCUBA tank which is hard to beat in price. For air pistol use, my Morini air cylinder has a volume of 0.08 L. I can fill that cylinder ~ 55 times until the SCUBA tank fill pressure reaches 150 Bar (2175 psi) from a 200 Bar fill. I get 'free' air refills (which don't include my time, energy, or fuel) from the shop I got the tank, but even a nominal fee of $10 makes would still be economical considering the number of fills and shot count.

Another thing to consider is the need for a high pressure regulator. Some claim to have the 'touch', but unlike a SCUBA tank - which is impossible to over pressurize the air cylinder, it its not difficult to over pressurize a 3000 psi air gun with a 6000 psi source. If you've got the airgun 'bug' and target air pistol is but one of many airguns, then a 6ksi N2 tank is more practical. But then, who ever said this hobby was practical? It never ceases to amaze me that people buy expensive world class target pistols then shoot the cheapest pellets they find, which to me is like buying an Aston Martin and burning quickie-mart gas. But, that's just me. If having a 6ksi N2 tank makes you happy, then go for it! Your airguns (provided you don't over pressurize them) will benefit from the ultra-dry pure nitrogen.

p.s. Where I am located, a 6ksi N2 tank would be leased and require access to the bottle delivery truck (these aren't 35 lb SCUBA tanks). I own my welding bottles, which are limited to 80 cu ft. I also have a shoebox compressor along with a Altaros booster.

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 12:02 pm
by hundert
TenMetrePeter wrote:don't try it with oxygen.
Thanks, I will try it with hydrogen then!

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 1:07 pm
by pbrejsa
Do not forget,that a mixture of hydrogen with air is explosive. The most important is health, especially mental.

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 1:41 pm
by Rover
Mental health!!! On Target Talk....surely you jest!


Waiting on William.....3,2,1, GO!!!

Re: High Pressure welding bottles

Posted: Mon Mar 20, 2017 5:03 pm
by william
hundert wrote:
TenMetrePeter wrote:don't try it with oxygen.
Thanks, I will try it with hydrogen then!
You can assure yourself medal after medal by filling your cylinders with chlorine. You'll win like you've never won before (doesn't the president insist it's all about winning?) as long as you take proper precautions - see pic. On the other hand, you may lose a few friends.

As a special bonus, you'll have a lovely coating of aluminum chloride inside your cylinders which ought to give you motivation not to try to extend their lives beyond 10 years!

Re: High Pressure welding bottles

Posted: Tue Mar 21, 2017 3:32 am
by TenMetrePeter
Talking of exotic gases, a friend of mine uses a most peculiar gas in his gun. Like nitrogen it needs to be separated from air in an expensive liquefaction process with a large carbon footprint. The power varies according to room temperature. It makes such a loud bang we all have to wear ear protection. He needs to put the gun cylinder in the freezer to get a decent fill. It rots through factory seals in a few years. If you leave it in the car on a hot day there's a chance there will be no roof on the car. Just trying to think of the name - ah yes carbon dioxide - crazy fool!

Re: High Pressure welding bottles

Posted: Tue Mar 21, 2017 11:30 am
by hurt
What regulator would be required for the high pressure nitrogen bottle?

Re: High Pressure welding bottles

Posted: Tue Mar 21, 2017 6:23 pm
by TenMetrePeter
we have been through this before with 300 bar Scuba tanks. You need a valve and adapter with a gauge on the gun cylinder side and a bleed on the adapter. You dont need a regulator, which in any case could be wound up by the previous user .