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Old acetylene tanks

Pete Deal

Stainless
Joined
Apr 10, 2007
Location
Morgantown, WV
I don't remember the cut off but up to a certain size you can own and exchange. At some point they decided bigger bottles you have to rent and exchange. In both instances the weld shop will only exchange their own branded bottles. Of course, there's lots of large tanks in the wild that people own, and shady places that will fill for you as long as it passes recert. In my area there's a guy in a van (down by the river) that will provide this service.
From my experience this is BS. One local supplier (Airgas) here tells me this same line. One down the road (Matheson) sells me the same big bottle the last guy told me i couldn’t own.
 
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Strostkovy

Stainless
Joined
Oct 29, 2017
From my experience this is BS. One local supplier (Airgas) here tells me this same line. One down the road (Matheson) sells me the same big bottle the last guy told me i couldn’t own.
Yeah, it's strictly what the welding suppliers are willing to sell. Our supplier lets us buy whatever we want, but we don't want to pay the steep up front price for dewars. They also won't fill specialty gases on bottles they don't own. I think this is because they have to have enough bottles on hand to keep filled for exchanges, and they have to have more if people are holding onto empty bottles. It could also have something to do with specialty mixes being sent off and filled by other facilities. I think I heard something about purity as well. I don't definitively know the actual reason.
 

dalmatiangirl61

Diamond
Joined
Jan 31, 2011
Location
BFE Nevada/San Marcos Tx
Sure, they have every right to not fill them, but what gives them the right to destroy your tanks? That's the bit that gets me
There are laws concerning the filling and recertification of these tanks, not sure but I'd bet they are required to render the tank inoperable, and mark it as such, so it does not get drug down the street to another establishment where the tank owners buddy agrees to refill it. Or they might just do it to cover their ass, maybe we should be thankful of that:scratchchin:

If your really interested here is some reading , scroll down to "Recertification of DOT 8 cylinders" for acetylene.
https://www.law.cornell.edu/cfr/text/49/180.209
 

Phil in Montana

Stainless
Joined
Jul 31, 2007
Location
Missoula Mt
It has to do with the acetone absorption of the core of the cly, as I have been told. Its only good for so many refills and really goes to hell if the cly is used on its side...Phil
 

DDoug

Diamond
Joined
Oct 18, 2005
Location
NW Pa
Sure, they have every right to not fill them, but what gives them the right to destroy your tanks? That's the bit that gets me
OP states they came back with valves removed, paint stripped, and marked condemned.
Hydro testing requires the valves be removed to doo the test.
Simply re-install the valves, and re-paint.
 

Strostkovy

Stainless
Joined
Oct 29, 2017
OP states they came back with valves removed, paint stripped, and marked condemned.
Hydro testing requires the valves be removed to doo the test.
Simply re-install the valves, and re-paint.
Paint stripped is a bit odd. Are these even the same tanks?
Why would you remove the paint from scrap that is clearly marked as condemned?
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
Paint is stripped for NDT..................fill ive seen is a mix of asbestos and diatomaceous earth,and sometimes magnesite to act as a cement..............the main offenders for damaging cylinders used to be the oil exploration industry.......... when business was great,they never bothered returning any cylinders.....the likes of Linde and BOC never charged them either..................neverthe less,I d treat any empty acetylene cylinder as dangerously explosive.....unless vacuum drained ...........acetylene is explosive in air in just about any mix where is even a molecule of oxygen...........its also dangerously explosive when compressed beyond 30psi,and in the presence of copper.,or brass...............where it reacts to produce copper acetylide.....a sensitive explosive..............the acetone fill can also be explosive if reacted with pure oxygen ............The guys working the feed grab feeding scrap into the fragmenter used to get "shellshock" from the repeated explosions of acetylene cylinders.......even though the crane has 60ft arms and triple armourplate windows.
 

magneticanomaly

Titanium
Joined
Mar 22, 2007
Location
On Elk Mountain, West Virginia, USA
Thanks for the replies.
I will have to call around and see what other supliers do, now that I have run into this issue. I understand some of this.
Settling of the filler could be a problem, because it creates a space for free C2H2 under pressure, which is unstable, which is the reason for shipping it dissolved in acetone in the first place. But there will always be a LITTLE space for the C2H2 to come out of solution so the acetone does not puke into the regulator. That is also the reason for a max safe withdrawaal rate.
But I do not see why a little more filler could not be added...except the desire to make me buy a new one.
Yes, I should bitch and try to get my valves back. I think they stripped paint to be sure i had not bondoed and painted over previous "CONDEMNED" stamping. I have seen C2H2 tanks with iron valves, but most are some kind of brass or bronze, so if the copper acetylide theory is true there are some Cu alloys which do not do that. I have dealt with tanks in two states NJ and WV. The laws are trange and change and are spottily enforced. In NJ I do not think you could own tanks above a certain size, but made a friend who had owned his since before the laws and had a budy who filled them. I bought some of his and had the same guy keep filling them Then I moved to WV and IIRC nobody would fill my tanks. Eventually made a friend who "had a buddy", and got my tanks filled through him. Of course he made somethin on the deal.
Eventually found a supplier who would fill mine (at a decent price) if i showed him a receipt for each tank showing that I had bought it from a dealer for the tank's mfr. Once he had a stack of receipts, I am pretty sure he did not check the S/N of each tank I gave him against his file of receipts. Happy-happy until now.
 

jim rozen

Diamond
Joined
Feb 26, 2004
Location
peekskill, NY
My understanding is that copper acetylides don't form on brass, only copper. I believe they use brass tubing and fittings to manifold cylinders together to allow increased withdrawal rates.
 

cyanidekid

Titanium
Joined
Jun 4, 2016
Location
Brooklyn NYC
ok, there are quite a few differences most have missed here. first, acetylene tanks are NOT high pressure tanks, (250 psi) they use an absorbent filler composed primarily of diatomaceous earth and acetone to absorb the gas in a dissolved state. completely different from the high pressure tanks that just pressurize the gas to 2500, second, there is a distinction in federal law (DOT) between tanks under 125 cubic feet capacity, and those over. the "standard" 330 CuFt tanks, which are not customer owned. these must be rented only, if transported on DOT approved means, but it is a bit of a scam all in all. there is a racket going on, and its a bit of a game to work out the best deal... and acetone tanks DO NOT get vacuumed out, but the high pressure CGA 580 "inert" gas tanks and medical O2 absolutely should. ive gotten argon tanks that were "manifold" refilled and really O2 contaminated that drove me apeshit before I figured that out... :D
 
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john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
I have not had acetylene since 1970,due to cost.........but my last job,the "boss" insisted I have 2 cylinders of acetylene on hand for the "Golden Ones" to do weekend projects ......these juvenile morons never turned off a valve ,and first thing every Monday I was down the gas sales shop to get 2x oxy ,2x acetylene.........anyhoo,the big acet was over $200 .....according to the shop owner ,mainly due to the massive insurance premium to carry acetylene.....and he could only have 4 cylinders in stock,and none in the building......they were in an enclosure out in the yard.
 

RC Mech

Stainless
Joined
Jul 21, 2014
Location
Ontario, Canada
Only owned tanks here, so not much help to the OP, but there’s quite a bit of misinformation about storage of acetylene above.

What the hell is a “dissolved state”? Acetylene is soluble in acetone, benzene and DMF. If you want relatively clean acetylene for heat treating finicky steels, carburizing or for lab work, it’ll be dissolved in DMF.

Acetone is cheap so commodity acetylene gets stuck in that. The porous mass is agamassan, the precise composition of which differs by gas supplier and lunar phase. Calcium carbonate and other cement ingredients. The fancy dirt may or may not be present.

As the internal cylinder pressure decreases (relative to the original fill pressure, 16-18 Bar) acetylene volatilizes into the gas phase. Cylinder headspace would be rife with acetylene, could undergo rapid decomposition should the cylinder be shocked by impact etc. Not ideal. The porous substrate allows for micro pockets of acetylene within it.
 

dana gear

Hot Rolled
Joined
Feb 27, 2013
Location
Northern califorina, usa
I own my own acetylene and O2 tanks. Do not need to pay rental or demurrage, whatever the racket is called. I am happy to pay the modest cost of periodic testing of the O2 tanks. Never had one fail, even the one made in the 1940's. I am careful with them all, re-paint as needed to keep them looking respectable.
Got a nasty surprise the last time I sent acetylene tanks off to be re-filled. Two of them (about 8 x 36 size) got "condemned". Returned to me with valves gone and paint stripped and heavily stamped "condemned". They did not blow up on a hydro-test. I tried to find out why. The dealer was not sure because they sent them elsewhere to be tested and filled, but he said the commonest cause of failure was settling of the absorbent fill.
Sounds to me like a stupid reason to destroy structurally sound tanks. Add some more filler! Or dump out the old shit and put new in!
I am posting here to find out if this sounds right to those who know, and who have no economic interest in making me buy new tanks.
Are there ways to maintain acetylene tanks to forestall this aging process (if that is really what is going on)? Some way to fluff up the old shit before sending them off?

Makes me want to build an acetylene generator!....if I can still buy calcium carbide.
That's simply wild. I have had owner acetylene cylinders fail the various tests/inspections before, but in all cases there simply returned to me in there complete form with a tag attached to the valve with a reason for failure. I have been told some fillers will X stamp out the ICC/ Dot numbers to render it unfillable if it fails.
Acetylene cylinders contents for the most part are about10 percent porous material of different designs, some company's use Calcium -silicate that has a porosity of 90-92 percent, very old cylinders actually used ground balsa wood for a time. The other volumes are about 42 percent acetone, 36 percent acetylene gas and a reserve of 12 percent for expansion, these percentages are ruff. What will take a acetylene cylinder out of the game, Damaged neck ring threads if the cylinder uses a neck ring, some don't, Arc strikes to anywhere on the cylinder, dents in the cylinder typ 3/8" or larger. early cylinders with weld rings on the bottom. any sign of fire damage. Any damage to any of the nomenclature of the top of the cylinder and or altered information. Cylinder bulging. External corrosion (rust). Cylinders are given an Ultra sound test and yes they should pull the valves and check compression of the porous material as well as the safety melt plugs for condition and leakage.
It's wild that your dealer would send what would be considered a hazardous material container back to you open to the elements with the valve removed.
I am only assuming the cylinder was M/T and devoid of acetone and even then a shitty move on the testers part. The jokers probably reused your CGA 510 valves.
 

JoeE.

Titanium
Joined
Aug 31, 2006
Location
Kansas
Local weld shop here in town used to be the distributor for welding gasses.
Back then I had a pretty good sized (I don't know the nomenclature regarding size/capacity. It's probably 12" dia.) acetylene cylinder that had the welded on base ring....
When I last emptied it and turned it in for refilling, the shop owner told me "hey, they won't refill that old thing because of the type of base it has..."
He showed me what he was talking about. Obsolete tanks~ the base/support ring on the bottom is basically a sleeve that slips over the O.D. of the tank itself, and is welded in place.
They condemn them because the junction of the two cylindrical surfaces is conducive to rust/corrosion and is not able to be inspected. So, the new cylinders are built different... the base butts up against the bottom of the cylinder and is welded there.
The reason these cylinders have a hollow bottom is because of the plugs that exist there. Other gas cylinders don't have them.
All this may be the reason your cylinders got condemned.
PS.. the last time I had my acetylene filled, it was $300+... and that was 10 years ago! I had left the valve open for a week before I discovered it and the contents leaked away... I about cried when I saw that!!!! Now, I hardly ever use the stuff... but every time walk past, I give that handle a twist to be sure it's closed!
 

Garwood

Diamond
Joined
Oct 10, 2009
Location
Oregon
I once picked up a fresh filled acetylene bottle, unloaded it in my shop and started working on whatever project which included MIG welding. I'm welding away and here this FUBOOM-BING. The floor shook. I'm looking all over the shop trying to find what heavy thing fell over and then I notice this big, black ring on the floor around the new acetylene tank I just brought in- The damn plug was loose in the bottom and the MIG spatter set it off, shot it in the air an inch or two, and it landed back down with a big DING.
 

john.k

Diamond
Joined
Dec 21, 2012
Location
Brisbane Qld Australia
if you are lucky an acetylene leaqk explosion makes a mass of black soot everywhere......if you are unlucky an acetylene leak explosion blows your shop to pieces and you with it....................id say at least once a year here ,a tradie blows his house to bits by failing to turn off the valves on mini oxy acetylene...........most recent one I recall ,explosion of a van damages 40 houses,five structurally ........and the blast also detaches the man opening the van door (probably light switch spark)from his head and legs,head goes thru a front window of a house on the other side of a 4 lane road........................Another did -ya-know?----the Myth Busters did a segment on a tradie van oxy acetylene explosions........the blast was so powerful ,the FBI forbid the program from being shown on telly.
 








 
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