I'm a newcomer to gas welding, and am looking for some advice on buying
I found a private party selling a used set of tanks. It sounds like a
reasonable deal. But, what should I look for? Should there be any papers
that come with the tanks stating they've passed pressure testing? If I
remember right, I recall hearing that tanks need to pass inspection
periodically. If they don't come with proof of testing, is that a deal
Also, any visual signs I might want to check for, or any other advice
would be greatly appreciated. Thanks!
The Moon is Waxing Crescent (9% of Full)
I don't trust buying used tanks from individuals, I buy my tanks from
one welding supplier. The cost for my tanks was around 475.00, when I
need a refill I take them back and they exchange them for full tanks
for around 65.00 for the oxy and 90 for the acetylene.
I've wondered if I pay too much myself, let us know how it goes.
You can certainly save some money buying welding cylinders used, but it is also
risky. Welding cylinders come in two flavors: owner and rental. Lots of
cylinders out there on the used market are actually rental cylinders, owned by a
welding gas company.
In fact, when you buy a tank, you buy rights to a tank. When it's empty, you
take it to a welding supply and swap it for a full one and just pay for the gas.
It isn't any fun at all to have the guy wheel your cylinders inside and then
come walking back out to tell you "Those are rental cylinders - we can't swap
them out for you. Thanks for bringing them back." You have no recourse and you
feel like you were punched in the stomach. (Don't ask how I learned this!)
What I suggest is to talk to a guy at a welding supply, and have his store's
phone number in your cellphone memory when you go look at the tanks. If there is
any raised lettering around the neck ring, call the welding supply and ask if
they're rental cylinders. Of course, if the seller has the paperwork that proves
they're owner cylinders, that's another story.
When you do get your cylinders, however you get them, the first time you swap
them out for full ones I strongly suggest you save the receipt as it ends all
discussion about owner/rental issues.
Finally, around here, if you get a cash account at the welding supply store, you
can often get a pretty significant discount and it becomes not that much cheaper
to buy cylinders from the welding supply, especially now that prices on
craigslist have shot up due to the zero cost of advertising.
1. It depends upon the size: 60 cu ft or less are "owned" bottles.
Greater than 80 are leased. 80 can be either. Rarely, large bottles
are owned e.g., military surplus. Large bottles will have a collar
with the owners name on it.
2. Gas suppliers usually just exchange bottles: you leave your empty and
take a full one.
3. My supplier doesn't care about certification. YMMV.
4. Small bottles are just exchanged no questions asked (they are always
owned). Large bottles are assumed to be leased and you take them back
to the lessee. Anywhere else will refuse them and may confiscate them
if you don't have the lease or bill of sale for those rare owned large ones.
Before I bought some used cylinders I wrote down the info stamped
on the cylinders and called my gas supplier (Central Welding) for
advice. They told me the following:
Here in Washington State they basically use two types of
cylinders. They are called "Owner cylinders" and "Leased cylinders".
The cylinders are in different sizes so that there is no need to look
at what is stamped on the cylinder. For example, an Owner cylinder may
come in the 80 cubic foot size and the comparable Leased cylinder will
come in the 100 cubic foot size. You want the Owner cylinders.
When I get my cylinders filled I trade them in for full ones
rather than wait for them to be filled. Not only is it faster, it is
cheaper also. When you keep your cylinder always eventually it will
need to be hydrotested. You will have to pay for this. When you trade
in your empty cylinder for a full one the gas supplier takes care of
the hydrotesting. So even when I buy a new cylinder, all pretty with
new paint and all, when it is empty I trade it in for a full ugly
The other replies are all of the map because the trade practices in each
regional area are all over the map and each dealer practice is all over
the map. You will just have to call around to the various dealers and
see what they have to say. Prepare to be completely confused. My take on
what I've seen;
In general, the smaller tanks are owned, larger are leased/rental. Lots
of gray are in the medium sized (122 cubic ft O2, 125 acetelyne)
Rental is a bad way to go, you pay a monthly charge of perhaps $1.50 to
$2.00, full payout is set for 5 years.
Leasing can be good or bad. I have a lease where I pay a deposit, I swap
the tanks when empty. If I want to get out of the lease, I bring the
tank back and they give me my deposit back. I'm happy either way. One of
the other dealers in town has a 5 year lease. Pay a deposit, you get the
tanks for 5 years. At the end of the 5 years the dealer keeps the
Purchased tanks are problematic. My neighbor owned a pair of tanks. When
he needed a fill he brought them in, they refilled the same tank, he
picked it up a couple days later. Two trips and out of service for two
days. Plus he had to pick up the recertification charge. (Bad deal.)
Other dealers may just accept your tank and swap a refilled one. No
recert charges. (Good deal) Then there is the tank that has been stolen
or 'converted' from a rental. Bring it in and they say thank you for
returning their property. If you purchase tanks from a private party,
make sure your gas dealer is good to go with the deal.
Read through the rest of the responses, everyone's hitting little
pieces of the full answer... ;-)
The "always customer owned" cylinders usually are under 3' tall -
the B and MC size acetylene, and 50CF and smaller oxygen are safe to
say "owned". If they own larger tanks, they'll have paperwork from
the local welding supplier with them stating so. And the leased tanks
are usually permanently marked on the neck ring as to the company that
owns them, call them for more information.
The Hydrotest dates on the tanks are only important if they are way
out of test, nowadays they figure that cost into the exchange and
refill fees. But to check, around the neck they have the cylinder
serial number, and the test dates. Good for 12 years.
Old markings are just month and year 8-93. New markings have the
month and year stamped in 1/4" characters, and a custom square punch
(2 characters top line, two bottom) with the 4-character code to
identify the hydrotesting facility in 1/8" characters instead of the
dash. Something like 8(B332)93 This way they can track the
cylinders' test history easier - especially if it ruptures...
If the tanks have big dents, big rust, or show other evidence of
being really banged around, you don't want them. You may not be able
to exchange them, since the suppliers don't want to give you a good
set of bottles and possibly have to scrap the ones you turned in.
If you take a questionable set of tanks and clean them up and paint
them, they may offer to take yours and test them, and if they pass
they'll fill them up and you get that set of bottles back. This will
take a week or two.
Read and heed the warnings - The cylinders are safe WHEN HANDLED
PROPERLY, and VERY DANGEROUS WHEN NOT. Always transport the bottles
secured upright, and NEVER in a closed trunk or passenger compartment.
They do blow up on occasion - Acetylene is flammable from (IIRC) 4% to
96% concentration in air, so leaks both big and small are dangerous...
The acetylene cylinders have fusible-plug thermal relief valves, and
both have pressure relief valves or rupture discs, and a hot trunk
will make them vent off. And acetylene occasionally becomes unstable
and goes "Boom!" all by itself when mishandled - Google up the term
"acetylene deflagration" for an eyeful.
Strap them in the back of a truck, or if you must use a car leave
the trunklid wedged open with a big cardboard box for ventilation.
Leave the supplier and go straight home and get the bottles into a
shady storage spot.
No cylinders in the backseat of a sedan, windows rolled up, parked
in the sun in your driveway or at the local Wally World... You'll
come out and find your car opened up like a flower and turned into
modern art. The pieces can go hundreds of feet and easily kill
NEVER run the acetylene regulator output over 15 PSI - it is
unstable as a gas over 15 PSI without the Acetone and the sponge
matrix inside the cylinder as a moderator.
Never draw over 1/7 of the acetylene tank capacity per hour, or you
start sucking out the acetone. Causes green spitting flames, not
good. This means you are restricted to the smaller tips when using a
B cylinder, and the tiny with an MC. If you want to use big cutting
or welding tips to do big jobs, you need to buy or lease the big
bottles or manifold several small bottles together - With a
purpose-built manifold system, see below.
Oh, and no copper tubing for Acetylene piping systems - pure copper
and brasses with too much copper in them can form unstable copper
acetylide compounds inside, and they can start off the "Boom!". The
brasses used in the welding regulators and piping adapters sold for
the purpose are safe, but plumbing pieces picked up at the local home
center may not be. No messing with unknown adapters.
Between this and everyone else who has already spoken up, That's the
--<< Bruce >>--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
If *I* was buying a set of oxt/acet tanks I'd go with the seller, and the
tanks, to a welding gas refilling shop convenient to your location and let
them tell you about the "true ownership" of the tanks.
I have bought so many used tanks that I have lost count. I have certainly
bought more than 30 welding tanks in my lifetime.
By my standards, the cost to hydrostat the tanks and get them certified
has to be ignored. The certification is for your safety. The cost of
certification is normally fair.
Large capacity tanks are heavier and somewhat more inconvenient to haul
around and to store than smaller tanks.
The cost to refill the tanks is greater (per gas volume) for smaller tanks
than for big ones.
Here's the straight skinny.
Bottles may be bought and sold unless they are the property of others. You
can recognize this by the neck casting that will have the name of a company,
such as AirGas, if they own it.
What happens is this:
You "buy" the bottles. You take them to a refiller. At that first
"refilling", which will merely be an exchange, they will look at the bottles
for about .37 seconds and either exchange them for you, or say that these
belong to another company, and they can't exchange them, or that these
belong to them, and confiscate them. If they belong to another company, you
can take them there, and if they are legitimately bought "owner" bottles,
they will merely exchange them.
The bottom line is .............. you won't know until you try to get them
"filled" / exchanged.
If they do it the first time, you're home free, with an account, and now,
bottles you got from that supplier. It is always advisable to stick with
one supplier. Others may trade, but you run into less chances of hassles if
the desk guy is having a bad hair day.
Nothing a seller says or does makes much difference unless it is giving you
a bill of sale for bottles HE legitimately bought. He can say and do
anything, but you will find out when you take them for refilling.
I would suggest that you invite him to take a ride to the refilling depot,
and you BOTH have a talk with the guys there, so if there is anything awry,
you will catch it BEFORE you give him the money.
Steve, who's had a lot of experience with owner/rental/lease bottles.
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