How LongWil lA 20 CF Argon Tank Last Title Image

Craving to do some MIG or TIG welding?

Excited to get yourself your first 20 cf Argon tank?

But right now you’ve no clue.

Running out of Argon gas. And before you’re halfway through your project will be super annoying. And then you’ll be running back to your gas supplier for another tank.

You’re desperate to find out how long it will last you.

Whether you’re buying or renting a 20 cf tank of Argon you want to be sure it’s the size you need.

You’ll find out right now how long your 20 cubic foot Argon tank could last.

Your 20 cubic foot Argon gas tank (this size of cylinder is also known as an R) could last you about an hour MIG welding.

And around half that time TIG welding.


TIG welding uses much more Argon gas.

And there some other things that affect your MIG or TIG welding time.

What things?

Read on to learn more.

How Much Gas Is Inside Your 20 CF Argon Tank?

The Argon gas inside your compressed gas tank is measured in cubic foot.

Your 20 cubic foot Argon tank will be filled with 20 cf of Argon. Or if your tank is tested and it’s certified for a 10% over fill you’ll find 21 cubic foot of Argon gas inside.

How can you tell?

Argon gas cylinders certified for a 10% overfill will have a star on the bottle along side its testing date.

Not sure how to read the markings on a gas cylinder including its testing dates. Take a look at this article.

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How Is Your Use Of Argon Gas Measured?

And when you’re using Argon gas your use is measure in cubic feet per hour (CFH). Or in liters per minute (LPM).

You’ll also see liters per minute written as l/pm.

Your gas gauge often has one side that shows cubic feet per hour. And the other side showing liters per minute.

Gas Regulator showing LPM
Gas Regulator showing LPM

Why is this important?

Liters per minute are roughly half that of cubic feet per hour.

And if you set your gas regulator gauge to the wrong setting you’ll use twice the amount of gas.

Much more than you need to weld with. And in no time you’ll have an empty Argon gas cylinder.

So it’s worth your while checking which side of the gauge you’re reading.

And what setting you’re using for your Argon gas.

That way you won’t be wasting the precious Argon gas in your cylinder.

How Nuch Argon gas Will You Use Welding?

When your welding thin Aluminum you’ll be looking to use a gas flow rate of 15 to 20 CFH or 7 to 10 LPM

When welding 16 gauge .060″ Aluminum you’ll be looking to use a gas flow rate of 20 to 25 CFH or 10 -14 LPM

Welding 11 gauge, 1/8th thick Aluminum you’ll be looking to use a gas flow rate in the region of 20-30 CFH or 10-16 LPM

What Does That Mean For How Long Your 20 CF Cylinder Of Argon Gas Will Last?

Running Your Gas AtWelding Time
15 CFH1 hour 20 minutes
20 CFH1 hour
25 CFH48 minutes

Your compressed gas cylinder with 20 cubic foot of Argon should last you an hour. When you’ve opened your gas valves and you’re running your Argon shielding gas at a rate of 20 CF.

Remember The Difference Between Cubic Feet Per Hour And Liters Per Minute

L/pm is about half the rate of CFH.

  • 7 liters per minute equals just under 15 CFH
  • 10 liters per minute equals over 21 CFH

If the Argon gas gauge you’re using only shows Liters per minute. Be sure to adjust down your gas flow rate.

Or you’ll use up your Argon gas far quicker than you planned.

But Your 20 CF Argon Tank May Last Less Than An Hour

There are several reasons why your 20 cubic foot Argon tank will last less than that.

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1. Leaving Your 20 CF Gas Valves On

Turn off your gas valves when you’ve finished MIG or TIG welding.

When you assume that your welder’s gas solenoids are a perfect fit. And you won’t have any gas escaping.

You will.

And when you don’t weld often. You could come back weeks later to do some more Argon welding. And freak out because you’ve run out of Argon gas.

Plus it’s a terrible idea to keep your welder’s gas solenoids under constant pressure.  They can weaken and fail.

Stepping away from your welding for a short while and want to leave everything set up, then fine.

Finished for the evening then turn those valves off.

2. When You’re New To MIG Or TIG Welding

If you’re a first time MIG or TIG welder you’ll be doing a lot of practice. Welding shorter bead lengths. Testing your settings, trying them out. And testing again.


You’ll have the pre and post flow of Argon gas.

What does this mean?

You’ll be flowing some gas ahead of striking an arc to be sure your weld starts off covered with Argon gas.

And when you’ve finished your bead length.

You know that last bit of welding you did?

Well you’ll need that shielded with Argon gas too.

MIG Weld Icon

3. When You’re Tack Welding A Lot

When you’re doing a lot of tack welding on your Aluminum. Then you’ll have even more pre and post flow of gas.

Short bead lengths are the same.

4. Where You Weld

There is also where you weld to consider. 

You don’t MIG or TIG weld Aluminum outside without protection from the wind.

Wind will blow your Argon gas away from your weld puddle and lead to porosity.

But even a mild through draft in your workshop will see you upping your Argon gas CF rate. And then you’ll be using more Argon out of your 20 cf tank.


Last Words

Your 20 cf Argon tank could last you as long as an hour and 20 minutes while your MIG welding your Aluminum.

Take into account your own situation. The thickness of Aluminum you’re welding. Your skills and where you’re welding. And count up the reasons why your Argon tank could run out faster.

You may find you’ve some solid reasons to get yourself a larger tank of Argon shielding gas.

Related Articles

Argon Tank Sizes For MIG Or TIG Welding

Reading Gas Cylinder Date Stamps And Markings

Before Buying An Argon Tank On Craigslist [Watch Out For]