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Does Acetylene Go Bad?

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You might be wondering what will happen to your tank of acetylene if you leave it unused for a long time.

Is it possible for it to go bad? Acetylene will not go bad, especially if the tank is stored vertically. Storing the tanks upright prevents the acetylene and acetone from separating. If the tank is placed horizontally, it must be position vertically for a while before use. This way, the gases can settle before they are released.

In this article, we shed more light on the shelf life of acetylene. We also discuss how long acetylene tanks are good for and round it off with what to do with old acetylene tanks. 

Does Acetylene Have a Shelf Life?

Welding equipment valve acetylene gas cylinder tank

Acetylene does not have a shelf life because the gas, on its own, does not expire. When acetylene is not reacting with another gas or substance, it will remain unchanged. You can leave the acetylene untouched for close to a decade and return to using it without any issues.

The only problem you may encounter if you do not use the gas for too long is separation. 

One trick you can use to keep your gas ready for use is to ensure it is pressurized. If your tank loses pressure, the acetylene will no longer be useable. When stored appropriately, pressurized acetylene is almost everlasting.

How Long Are Acetylene Tanks Good For?

There is no set time or date that defines how long acetylene tanks are good for. However, they can expire in a way.

When the acetylene tank no longer performs as it should under normal circumstances, then it has expired. A tank with a leak or a tank lacking proper pressure can be dangerous. 

Although your acetylene tanks can expire, their shelf life is not predetermined. Typically, they can and should last for several years. However, if you suspect that your acetylene tank has become unfit for use, you can have it inspected. 

Inspections and Tests of Acetylene Tanks

Your acetylene tank should have a manufacturer and inspection date stamped into the metal of the tank. Tank inspections are necessary to ensure the safety of anyone around the tank. The tank inspections take place every 3, 5, or 10 years. 

A hydrostatic test is performed on the tank to ensure it is still safe to use. This test is vital as it checks the tank’s structural integrity when holding compressed gas.

The test is done by filling the acetylene tank with water. Then the tank is pressurized to about 150%, which is above its operational pressure. 

The hydrostatic test measures and records the expansion of the tank. It ensures the tank does not exceed a specific limit. Beyond this limit, the tank would be considered unsafe and unusable. 

The reason water is used for the test is that it cannot be compressed. Water helps to reveal any change in the shape of leaks of the tank as pressure is applied. 

Acetylene and gas steel tanks for welding

Once your acetylene tank is tested, it gets stamped with the inspection date. This acts as a reminder for the next inspection date. 5-year tank inspections are most common, followed by 3-year tank inspections.

You may not be required to get another tank inspection for 10 years only under certain circumstances. The tank’s psi level may also be stamped with the inspection date, and for your safety, do not exceed it.

When your acetylene tank starts to get old, it will lose some of its structural integrity and the tank will be unable to hold as much pressure as it used to.

Filling tanks that are out of test date or damaged is dangerous and illegal. Do not fill any gas tank out-of-test date until it is tested and stamped by an approved test station.

How Dangerous Are Acetylene Tanks?

Acetylene tanks are potentially dangerous fire hazards. The hazards posed by acetylene are unique. This holds due to its transportation requirements, high flammability, storage, and instability.

Acetylene is quite unstable under high temperatures or pressure. If not well handled under these conditions, it may decompose and explode. 

One must never store or transport acetylene tanks in a closed vehicle. They may explode due to acetylene vapor buildup and a trigger. In past occurrences, explosions were triggered by a spark from the electrical system of the vehicle.

How to Store Acetylene Tanks Safely

Welding equipment acetylene gas cylinder tank with gauge regulators manometers.

The following summarizes how to store acetylene tanks safely:

  • When storing, transporting, or using acetylene tanks, always ensure they are in an upright position.
  • You may also secure the acetylene tanks with secure restraints like safety chains. Rough handling an acetylene tank can lead to a delayed explosion. It is essential for storage facilities to secure acetylene tanks from being dropped, being impacted by falling objects, falling over, or striking one another. It is best to store acetylene tanks in a strong gas bottle cage. It will help protect the tanks from any form of impact.
  • When storing acetylene tanks away, ensure they have valve caps installed.
  • Keep the tanks in well-ventilated areas.
  • Be extra careful when dealing with small acetylene tanks that do not have valve protection caps. 
  • Always keep your acetylene tanks from any external source of heat. Acetylene tanks are not designed to handle temperatures exceeding 125F (52C).
  • Keep the tank away from an oxygen tank. Acetylene tanks must also be kept 20 feet away from an oxygen tank or separate with a fire-rated wall 5 feet high. 
  • Do not place an acetylene tank on its side. This will cause the binders and acetone to be dislodged. This, in turn, will result in the formation of an acetylene pocket which may be subject to polymerization. Consequently, liquid acetone will be released into the regulator.

What to Do With Old Acetylene Tanks

Old gas cylinders for welding and cutting

If you are unsure of what to do with old acetylene tanks, you may trade them in or sell them.

They must meet these requirements:

  • No sign of physical damage.
  • Does not contain asbestos filler material.
  • The fusible plugs are intact.

Some places may charge you for testing, while others will not.

Apart from trading or selling your old acetylene tanks, you may do the following:

  • Donate your old tanks to a local welding supply store.
  • Dispose of your old acetylene tanks. The proper way to dispose of these tanks is to slowly relieve the pressure of the gas and remove the valve. Next, drain the liquid acetone, fill it with water, and cut the tank.

Cutting the tank allows you to remove the filler material towards the neck end. Depending on what it is, pack the filler up and dispose of it properly, together with the acetone. You can either cut the tank in half or cut a large diameter hole to prevent any repair.


Acetylene does not go bad, provided you store the tank in an upright position.

The tanks can last for several years, provided they are tested to ascertain their usability. Nonetheless, if you notice any damage to the tank, do not take any chances until the tank is tested.

All in all, acetylene and its tanks are dangerous. So, they should be stored properly to avoid any explosion. 


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Saturday 15th of January 2022

Thanks for the informative article, had some old tanks and this answered all my questions.