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Military Gas Bottles

Scottneh

Plastic
Joined
Mar 19, 2017
Hi everyone, I have a question about military gas bottles. To the moderator, I recall a post on here a while back about gas bottle history/age but for the life of me I cannot find it. If you know where it is, feel free to point me there and I will move this post there is appropriate.

Almost two years ago I bought a lot of 250 and 300 size gas bottles. What's left are four bottles with military markings on the neck ring. One even says US Army Air Service and was first stamped in 1944. My plan with them is to repaint them (blue, olive drab, etc) with the period correct insignias and sell them locally. When I went to have one hydro tested I was told it needs to have a "SOLD" marking on it. These bottles were in the mix of the lot and the business I bought them from was legit so I assume they came to him on exchange.

I don't want to lose the tanks so I was told to just stamp it myself. I don't want them to look like crap so my question is if anyone has an example of what the sold stamp looks like. i.e. is it just letter stamps, any idea what the size should be. Pics of other military tanks would be great.

Thanks
Scott
 
Let's get one thing very clear here before going any further.

Are you intending to stamp these yourself, and then sell them for actual hi-pressure usage ?
 
On a trip out East, I saw a gift shop that sold gas cylinders with the bottom cut off and an eye bolt screwed into the top. They had been made into wind chimes/bells. Looked like a great way to salvage old tanks.

Larry
 
I bought some big round bottomed oxy cylinder s from the Aust army once,one was covered in proof test stamps going back to 1916.The local gas supplier ,BOC,wanted a hydrotest everytime the cylinder was filled.Extra $200,cheaper to pay their ripoff rental.....I cut them for heavy wall tube.
 
I think he wants to stamp a mark that shows the cylinder is no longer Government owned. Shows the government sold it as surplus.
I understand some hydrogen cylinders are marked with a square with a plus sign dividing it into quarters. These were Nazi made and marked with a swastika converted to the square after the war.
Bill D.
 
Hi guys,
I can confirm that one.
I used to teach jewelry casting, using a hydrogen/oxy torch to melt with. The local gas house only had a couple of bottles painted up for H2, and one of them did actually have the "plus in a box" stamp that they used to obscure the swastika. All they really did was use a straight cold chisel to fill in the outside frame of the swastika, so it looks sort of like either a plus sign in a box, or a kid's drawing of a 4 pane window.
The origin of those tanks (as I was given to understand) was postwar GI's coming home with their gear after being posted to West Germany in the late 40's and 50's. It was a whole lot cheaper to buy tanks there, and let the army ship them home after PCS. So a whole bunch of German tanks ended up over here. That tank's first hydro was sometime in the 30's as I recall, and it was still going strong in 2010. Not too shabby.
FWIW,
Brian
 
Did the seller tell you you will be able to service and fill them? If you paint them you will likely fail visual inspection. Same if you 'unofficially' impress markings in the surface. There may also be a 'SP' number (as it is a gov't cylinder) which means special permit # and that is likely expired, if checked. Maybe with a bill of sale you can get a testing facility to mark or test them. Call around, but I wouldn't bank on a good outcome. Plumb them into an air compressor for extra storage.
 
Did the seller tell you you will be able to service and fill them? If you paint them you will likely fail visual inspection. Same if you 'unofficially' impress markings in the surface. There may also be a 'SP' number (as it is a gov't cylinder) which means special permit # and that is likely expired, if checked. Maybe with a bill of sale you can get a testing facility to mark or test them. Call around, but I wouldn't bank on a good outcome. Plumb them into an air compressor for extra storage.

I'm a certified scuba tank inspector and own about 50 tanks, ranging from 6CF to 440CF bottles. I have receipts for the big tanks, but have never had to produce one for a hydrotest. (It probably helps that I have about 10 tanks tested a year.) That said, many commercial testers are also gas suppliers, and they are often suspicious about privately owned cylinders being stolen. They are within their rights to ask for proof of ownership because theft is pretty common. Unfortunately. You might possibly get a better reception with a fire equipment shop. You can find a list of licensed hydrotesters online, listed by state.

That said, steel tanks are routinely painted, touched up, and repainted. This is not an obstacle to visual inspection or hyrdotesting unless the inspector has reason to believe or suspect that the tank owner used filler to hide external pits that would cause the tank to be failed.

SP tanks are a potential problem, but I have never seen a storage bottle with a Special Permit certification. If does have one, then as you say the manufacturer needs to renew it with the DOT periodically, and the SP must be current before the tank can be hydrotested. Manufacturers generally renew their SPs faithfully, though some are a bit lax about doing it on time. Of course, if the tanks made under and SP are found to be unreliable, the SP won't get renewed.

No marking on a neck ring (the things are removable threaded collars) will impede a visual inspection or hydrotest. You could even drill holes in the thing so long as you don't drill holes in the tank.

Once hydrotested, the tank can be returned to high pressure service and used in interstate commerce. (If it will be used for O2, it must be cleaned first.)

My guess is that, like most older tanks, these are just regular 3AA steel tanks. The OP should look for "3AA" followed by the service pressure. Something that old might well have a service pressure of 2400 PSI, and if so would be marked 3AA2400.

One problem that is common with older storage tanks is that the (tapered) neck threads might be worn from repetitive removal and installation. There are oversize valves available if the current valves cannot be installed to spec (so many turns from hand tight to tight, with so many threads showing above the neck), but I don't know how many oversizes are available.
 
So basically what I said with a little more detail. Kinda like - if you use it for O2 you will need the appropriate valve and tank marking in addition to proper cleaning. A scuba tank inspector adds no credibility over having basic regulatory knowledge. I am a certified technical gas blender (t/m) DSAT # 0412088528 and a certified O2 Service Technician - TDI # 145219, big deal and so what... both of us are stating common knowledge basics. By the way, good luck with the fire station tip unless you are buddies with the fill attendant operator. That concept stopped being feasible 20 years ago.
 
I think he wants to stamp a mark that shows the cylinder is no longer Government owned. Shows the government sold it as surplus.
I understand some hydrogen cylinders are marked with a square with a plus sign dividing it into quarters. These were Nazi made and marked with a swastika converted to the square after the war.
Bill D.

We occasionally had WW2 era Luftwaffe marked Oxygen bottles that were still in the regular rotation when I worked the flight line. We cascade filled the aircraft O2 systems after each flight, and went through a couple dozen bottle a day in the carts we used.

Some interesting reading on the sides of some of those bottles!

Honestly, I think worrying about the markings is time wasted. But, I would be looking to have the hydro test shop use their stamps to make any marks.

Personally, I think a great jeebus wind chime right next to the neighbor's corner of the property, would be a great way to get them back for their barking dog! :)
 
So basically what I said with a little more detail. Kinda like - if you use it for O2 you will need the appropriate valve and tank marking in addition to proper cleaning. A scuba tank inspector adds no credibility over having basic regulatory knowledge. I am a certified technical gas blender (t/m) DSAT # 0412088528 and a certified O2 Service Technician - TDI # 145219, big deal and so what... both of us are stating common knowledge basics. By the way, good luck with the fire station tip unless you are buddies with the fill attendant operator. That concept stopped being feasible 20 years ago.

We share those certifications, as it happens. TDI and PADI advanced blender certs, TDI tank inspector. One of them includes O2 clean tech (I forget which).

However, I was not suggesting he seek fills at fire stations. I was suggesting he seek hydrotest facilities other than those owned by gas suppliers, who tend to be more suspicious of tanks they might presume to be stolen. Also, I disagreed that painting steel tanks made it unlikely that they would pass a visual inspection, and that anyone would care about additional markings on a tank ring. On your other points, I think we agree.
 
The OP bought a lot of 250 or 300 bottles, his words. He should have a receipt for this purchase which would include the purchase of the military tanks. This should be sufficient proof of ownership for the hydro station.

Vlad, a former hydro station operator.
 
No marking on a neck ring (the things are removable threaded collars) will impede a visual inspection or hydrotest. You could even drill holes in the thing so long as you don't drill holes in the tank.

How is the neck ring removed? My new shop has a choice of 2 gas suppliers, both have given me option of I produce a tank with their name on ring, or no name on ring, and they will swap out full bottles. I found several tanks cheap, but name on them is the old (now defunct) gas supplier in town. Or I cough up $450 per bottle to buy from them.....there is no rental option.
 
I currently have a bottle that the name on the ring was ground off and painted over, still says "propery of" on it. I try to get either linde bottles or second choice is bottles with a blank ring on them, both types can be exchanged almost anywhere. If they ask why I say it is because I am doing work out of town and may need a refil.
I think the ring is crimped or pressed on.
Can you not take it to someplace else and exchange it? Ask for linde or blank.
 
My motto and .02 is don't fuck with pressure vessels.
Follow the guide lines and pay the money, you only get one life.

As far as I know :D
 








 
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