You want to weld Aluminum and you know you're going to need some Argon gas. When you are new to welding with gas it's hard to know how to go about getting some. You need to know what the available Argon tank sizes are and what is the right Argon tank size for you.
And importantly how avoid trouble by accidentally purchasing a stolen cylinder. Here are some tips and tricks to getting what you need.
What Argon Tank Sizes are There?
Tanks can also be known as cylinders or gas bottles. The sizes of Argon tanks vary from small and portable to large and weighty. The gas inside the cylinders is measured in cubic feet.
Luckily cylinders last a long time and their life span is tens of years if kept well and with consideration.
Most Common Argon Tank Sizes and Volumes Are
Argon Tank Sizes Chart
The sizes shown above are estimates/averages. Manufacturers of tanks vary their sizes and weights. This makes it easier for certain suppliers to identify, which are their tanks.
The table above should give you a good starting point for the more common cylinder sizes and the amount of Argon gas they hold.
The 'S' size shown, depending on the supplier could hold 125 cubic feet of gas or 150 cubic feet of gas. Double check. Some distributors call a 40 cubic foot tank a 40 some call it an RR.
TIP: Use the guide and see how it compares to what is supplied in your area and how compressed gas cylinder sizes are referred to.
Isn't There a Standard For Argon Gas Cylinder Sizes?
The truth is not really. There are more common Argon gas cylinder sizes, the ones I have listed above.
However the trick manufacturers have is to use uncommon Argon gas bottle sizes so that they can easily identify their rental tanks and retrieve the ones, which have been stolen.
Tanks mysteriously disappear from building sites, out of cages, off the backs of lorries and are sold privately to the unsuspecting.
TIP: Don't be taken in by the tank colors and think that there are standard colors for compressed gas cylinders with certain gasses in them. There are not. Only go by the data label on the tank and what it tells you is in the tank.
TIP: If the label on the compressed gas cylinder is missing pass it by. Because it could hold highly flammable gas inside, noxious gas - who knows!
Important Marks on an Argon Gas Cylinder
It is important to understand some of the marks on an Argon gas tank and what they mean as it could keep you out of trouble.
In the US the transportation of high pressure gas cylinders is regulated by the Department Of Transport (DOT). They stipulate the regulations for the safe movement of compressed gas, the markings and the testing of cylinders.
Gas tanks have a stop valve at the top and it's important that this valve is not knocked or damaged during transportation.
You will often see that the valve is protected with a collar.
Argon tanks have CGA 580 stop connections on the valve so that they can be connected to the correct and compatible regulators and hoses.
DOT-3AA gas cylinders must be safety tested every 5 years as a minimum. Either hydrostatically or ultrasonically and generally have an unlimited life span.
What to Look Out For
In the example picture above the two squares highlight the testing stamp marks.
The first square with 01 in it means that the last safety test was done in January and the second square with 14 in it means that the test was done in 2014.
This Argon gas bottle was last tested in January 2014 and the test remains valid for 5 years unless you find other stamps beside the test date.
There are other marks on this tank. The tank is stamped with a plus sign next to the date. This means that the cylinder is tested and rated for a 10% over fill. Useful if you are trying to get as much cf (cubic feet) of Argon into a tank and save money and trips for refill. There is also a star stamp next to the plus sign which means in addition this cylinder is tested and rated for a 10 year span between testing.
Putting it together, this cylinder was hydrostatically tested in January 2014, it is tested to allow for a 10% overfill and the star means that this bottle does not have to be retested until January 2024.
Some tanks are ultrasonically tested
Let's have a look at another tank
There are several stamps on this tank. The first stamp of 12, 91 means this tank was tested in December 1991, it has a plus and a star following the date that shows it was good for a ten percent overfill and didn't have to be tested again till Dec 2001.
The second stamp shows it was then tested in March 2003. The 03, 03 shows that. The date is followed by a plus and a star and the letter UT. The letter UT means it was ultrasonically tested.
The last stamp is 8, 14. So it was last tested in August 2014. The plus and a star along side means it is good till 2024 August and is rated so you can have a 10% overfill.
TIP: No star alongside the date shown, would mean that the tank needs to be tested 5 years from the month and year stamped on the tank.
YouTube Video on High Pressure Cylinder Identification
Here is a great video on what you should be looking for on Argon gas tanks and their sizes. I've extracted some screen shots above and here is the video itself. It runs for 9 or so minutes. It's a good one.
High Pressure Cylinder Identification
Video Credit : Holston Gases: Nathan Farquarson
The Hydrostatic Test What to Know
The Hydostatic test is done every 5 years or every 10 years for bottles with a star on them. The test involves testing the bottles for strength and leaks. Usually the test involves a visual inspection for any obvious damage. The tank is filled with water (sometimes oil is used) under pressure. The tanks are often immersed in water that is calibrated to show any change in volume of water. A change means that there is a leak or pressure loss.
What Argon Bottle Size Will You Need for Your MIG Welding?
What should you bear in mind when deciding on the right Argon bottle size for you? The tips and tricks.
1. How far do you live away from an Argon gas supplier to get refills? The further you live, the more it costs you in time and a tank of gas to get there. It may be better to consider larger cylinders and so need to make fewer refill trips.
2. How many suppliers of Argon gas do have in your vicinity? Check around. Argon gas prices can vary widely by supplier and by county. It could save you lots of dollars to find a good price competitive supplier.
3. Do you have a local HVAC gas distributor? A little trick to know is that you may well be able to get refills of gas from them on the cheap.
4. Find out what Argon bottle sizes you can get supplied. Under what conditions and at what price.
5. Can you get bottles tested locally? If you decide to own your bottles they will need to be safety tested at some point. What is the cost of the test? Again availability and costs can vary.
6. What can you safely transport? The bottles really needs to be upright and strapped in when transported.
7. What do you have to transport the bottle in? Truck? Car? This can dictate the Argon bottle sizes you can transport yourself.
8. What can you lift? Do you need to go up or down stairs to where you MIG weld? Some suppliers are relaxed about the Argon bottle sizes you take for refill as long as you can shift it yourself. Take another look at the table on Argon tank sizes above, the large cylinders are really heavy.
9. Cost of delivery? If you can't lift it or transport it yourself you're gonna need it delivered.
How Long Could a Bottle of Argon Gas Last Me?
Argon Cylinder Sizes and Welding Time Chart
Gas Volume in Cubic Feet
Estimate of Time
1 - 1.5 hours
2 - 2.5 hours
3 - 4 hours
4 - 5 hours
6.5 - 8 hours
7.5 - 10 hours
12.5 - 16.5 hours
16.5 - 22 hours
The figures in the above Argon Cylinder Sizes and Welding Time Chart table are estimates based on run time of the gas at 15 to 20 cubic feet per minute.
Note that in the 'real world' weld time includes other considerations.
- Because when you weld, you have the pre-flow and post flow use of gas. So your actual usage may well be higher.
- If you do lots of tack welds and short bead lengths you will probably run through your bottle of Argon gas sooner.
- When you are learning to weld Aluminum you will run through Argon gas quickly because you'll get things wrong, try again, and eventually find the settings you want. It could well be better to go for a 125 cf (cubic foot) Argon tank or 150 cf as the cost per cubic foot for refilling would be more cost effective.
Go for the biggest cylinder you can get away with and can afford. Argon gas doesn't go off.
How Often will you Weld?
Often you are recommended to go for smaller Argon gas tank sizes if you don't weld much but it may be better for you to go for the largest tank you have space to store.
TIP: Larger Argon gas tank sizes are more cost effective and again Argon Gas doesn’t go off.
You need to work out the price of a larger Argon tank compared to a smaller tank.
TRICK: How many smaller cylinders will you need to refill before you cover the cost of a larger one.
Particularly if you live some way away from where you can get the tank refilled.
TIG versus MIG use
Welding Tank Sizes and Portability
If you plan to port your MIG around then smaller tanks may make sense for you and then you accept the increased cost for greater portability.
There maybe benefits for you having 2 welding tank sizes the same. If one goes empty you don't have to stop mid project to run out to get it filled. No worry about how much is left in the tank and if you can complete your project.
You can carry on till the bottle is empty then swap.
If you have to wait a few days for your local welding suppliers to fill your owned bottle for you. You have another bottle that you can continue with straight away on your project.
Argon Tank for Your MIG Welder, Owning Versus Renting
- You buy the tank so you own the tank.
- You pay for the safety test - Hydrostatic or Ultrasonic test when it is due.
- It's yours. Any issues with the tank that means it is no longer suitable for refilling means you need to buy a new one.
- The tank is yours to keep, store, use as little of the Argon gas as you like with no on going costs.
- Owing your bottle can be a good idea as the value of bottles rises in price over time.
- Take into account not just the price of the Argon tank but the cost of the refills per cubic foot, plus taxes and HAZMAT charges.
Leasing or Renting
- Leasing or Renting means that the company who supplies you the tank owns the tank, does the testing and you don't have to worry about accidentally buying a stolen tank.
- You pay a monthly or yearly charge.
- If you use the Argon in the tank occasionally or not for six months you still pay. So a tank of Argon can get pricey for occasional use.
- There are no upfront costs for the tank.
- Refills may be cheaper, and quicker as they usually swap out your tank for a full one.
- You don't pay for testing.
- You may need to pay a deposit on the bottle. If you do it is worth finding out how much it is.
Possible issues with Owning an Argon Gas Tank
When you get it refilled, will you have to wait to get your tank back or do they swap out your tank for a filled one of the same size? Find out, as that could be a consideration in your town or district.
Some places get really funny about filling customer owned Argon tanks over 125 cubic feet in capacity. If you decide to own a large tank can you get it refilled?
When you put in your owned bottle will they refill your bottle while you wait or do you have to come back if they are busy?
What is available in your Local Area?
To a large extent you are going to be governed by the policy of your LWS (Local Welding Suppliers).
Do they treat 125 cf or 150 cf and under as owner owned or over 150 cf tanks as rental tanks only.
Purchasing an Argon Gas Tank
Argon gas tanks can be found at auctions - check out the companies that are going out of business, they may be selling off their tanks.
TIP: Beware of those companies who have been taken over or bought out by someone else as their tanks may well have transferred ownership.
Argon Gas Tanks on Amazon
I have done some research on your behalf and interestingly, Amazon.com has the following Argon tanks sizes for purchase. If you click on the links and go through to Amazon you can check the prices for yourself and compare them to the prices you're being charged for tanks locally. (Commissions Earned From Amazon Links Below)
Gas Volume in Cubic Feet
20 cf Argon Tank Size
40 cf Argon Tank Size
60 cf Argon Tank Size
80 cf Argon Tank Size
125 cf Argon Tank Size
250 cf Argon Tank Size
And there are options for the Argon tanks to be supplied full or empty.
Check what the situation is in your area for the refill of customer owned tanks if you would like to get one.
If you can get a good deal on gas then this may well be an ideal option for getting an Argon gas tank of the right size delivered.
Buying an Argon Tank on Craigslist
It is not unusual to find pre-owned Argon tanks on Craigslist but beware that the tank isn't a stolen tank.
Check for a company name or mark or manufacturers name on the ring. Does the ring say rental. Check for the same on the tank itself.
The above picture shows an Argon gas tank with a collar. The collar has the owning company name on it and what is more the company stamp on the cylinder itself. This is not what you want to see.
It means that the tanks are owned by that company.
Or it could mean that you are locked into a particular supplier for refills for that tank.
Is that supplier in your county?
If you take the tank elsewhere to get it refilled you could find at best the distributor refuses or they confiscated the tank to be returned back to the company.
TIP: Check the date stamped on the tank; you want to buy a tank that is within its testing dates.
A gas dealer won't refill an out of testing cylinder.
If the tank is out of its testing date then you will have to pay for a test. What is the price of testing locally around your home? What if it does not pass? The tank will be taken from you if it fails testing.
Check that there is no rust on the bottom of the bottle or damage around the cap valve.
Check out the situation in your own area for refills for the size of tank you are buying. Some local welding suppliers will only refill their own tanks or customer owned tanks of certain sizes. You may not be able to get the tank refilled where you live.
Safe Storage of Your Argon Cylinders
- Your Argon Cylinder should be stored somewhere cool out of direct sunlight.
- Preferably somewhere dry to prevent rusting of the cylinder.
- The tank stored upright.
- Take off the regulator when the Argon gas tank is not in use. Close fully the cylinder valve and put on the safety cap.
- When moving tanks, gloves should be used, safety glasses on and steel toe capped shoes on your feet. A cylinder falling or one dropped on your toe or foot will earn you a trip to the emergency room.
- Inspect the cylinder valve for damage, wear and tear regularly.
- Check the cylinder itself for rust.
- Secure the cylinder to a wall, running gear or other stationary support with straps or chains to prevent the tank being knocked over.
- Do the same for transportation. Secure the cylinder with straps, chains and transport the cylinder upright. You don't want the cylinder bumped or tipped.
Getting your Tank Safely Back Home
Argon is an inert gas that can and does displaces the oxygen in breathable air in an enclosed space and can cause suffocation.
It is best not to transport your Argon gas cylinder in an enclosed car. Give yourself plenty of ventilation.
Here is A little Story For You
Argon gas is used for the industrial and humane slaughter of birds because it is colorless, odorless and tasteless and quickly causes suffocation.
Don't be a chicken.
Transport, store and use your Argon gas with plenty of ventilation.
Thank you for making it to the end of my article. I hope you found its advice helpful in your learning what Argon tank sizes there are available. How to choose the right size of Argon gas tank for you.
And whether you choose to buy or rent or lease your tank of Argon gas, you now know the options and the possible pitfalls, the tips and tricks of doing it.
And feel confident and able to make the right choice for your MIG arc welding.