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My neighbor recently purchased a 60 cubic feet argon tank for his at-home TIG weld, but he kept complaining that the gas was running out sooner than it was supposed to. He had even set the argon flow rate as intended by the manufacturer. So I decided to help the guy out and did some research on how long argon lasts during TIG welding. After a few hours, I figured out why my neighbor was having a problem.
How long should a tank of argon last for TIG welding? The average industrial supply tank of argon gas, at around 250 cubic feet, will last about 10 hours at a 20 – 25 cubic feet per hour flow rate. Most household tanks are between 60 and 80 cf, and at a 20 cfh flow rate will last around 3 to 4 hours.
However, the lifespan of your argon tank during TIG welding may vary as it depends mainly on your bottle size, the flow rate, as well as pre and post-flow losses. Read on to find out what you can do to extend the duration of use on your argon tank.
What is Argon Flow Rate?
In welding terms, flow refers to the amount of gas being released at any given moment. Flow also indicates the consistency of the stream of gas released.
The better the flow, the more consistent the release, the better the weld.
To calculate your flow rate or how long your argon tank should last, you need to consider the size of your tank or bottle and how much gas is being released during the welding process.
Argon tank sizes are measured in cubic feet (cf), and the flow of gas is measured in cf per hour (cfh). So a simple formula is formed showing how long a particular size tank will last.
Tank Size (cf) / Flow Rate (cfh) = How Long a Tank of Argon Will Last (hours)
|Flow Rate in cubic feet per hour||60 cubic feet tank||100 cubic feet tank||300 cubic feet tank|
|5 cfh||12 hours||20 hours||60 hours|
|10 cfh||6 hours||10 hours||30 hours|
|20 cfh||3 hours||5 hours||15 hours|
Most industrial-sized tanks are around 300 cf in size as they are relatively easy to handle, and given the large size, they are more effective. Large TIG welding power supplies have adjustable features so you can control the flow rate and other features to maximize your argon use.
If you are looking for something less heavy-duty, a 60 cf tank is your best bet for the home, but it is not going to last proportionally as long as a larger industrial tank.
A long-term and cost-effective tank is something between 220 and 300 cf.
However, neither the formula nor the table above is entirely accurate in terms of how long your argon tank will last.
The numbers and figures don’t take into account a few essential factors, including time taken for pressure build-up and, most importantly, how many times you turn your TIG welding power supplies on and off.
This will initiate the pre-flow and post-flow adjustable features described in detail below.
Don’t Forget to Take Into Account Pre and Post-Flow.
Now before you consider the average flow rate during your TIG weld, which is measured in cubic feet per minute or hour (cfm or cfh), you should keep in mind that there is a period of gas flow before and after you start to weld.
These intervals are referred to as pre and post-flow, and they often account for a noticeable amount of argon gas release. Most TIG welding power supplies include these features.
This is something you need to take into account when calculating how long your argon tank should last.
During pre-flow, the feature gives you the ability to shield the weld area before you start welding. Once stopped, the post-flow feature keeps the gas flowing for some time until the welded area can properly cool down.
If you are using a smaller tank, around 60 cubic feet, these features are going to eat up your expensive argon gas very quickly. To avoid too much loss, it’s recommended that you adjust the discharge of post-flow to 1 second for every 10 amps of welding current.
What About Pressure?
Remember when we were talking about the consistency of the stream of gas? Well, the stream is essentially the build-up of pressure inside the argon tank, which allows for the gas to be released and flow.
The pressure is measured in pounds per square inch or psi, and most welders note that their average argon pressure gauge for a TIG weld is between 18 and 28 psi.
During the welding process, you will likely need to take breaks in order to allow the pressure inside the tank to build back up and release a more consistent stream of gas.
Why Use Argon?
TIG welding using argon gas is one of the more preferred and common methods of welding as it has no filler material, it’s better for the environment, and you are in full control of the outcome.
Argon is an inert gas, so it does not oxidize or interact with anything that would otherwise create burns or pours.
By nature, argon use in TIG welding means a slower, more controlled process, producing a quality weld every time. However, the more gradual welding process means more gas is used, resulting in a more expensive operation.
Another common gas used in welding is helium, but unlike argon, the welder has less control over the outcome of the job, which often results in an imperfect and low-quality weld.
Some individuals may resort to using a mix of argon and hydrogen, an active gas, in an effort to save money and speed-up the welding process. Although this is a somewhat effective means, it is likely that the weld will end up with small openings and pours with air bubbles inside.
This lack of structural integrity effectively minimizes the strength of the joint. It’s probably best to stick with argon, sure it’s expensive and slow, but it gets the job done.
So What Can I do To Maximize My Argon Gas Use and Minimize Flow Rate?
By now, you have figured out that the slower the flow rate on your argon tank, the better the outcome on your TIG weld. However, because this practice is the more expensive option, you can do a few things to maximize the time it takes before your argon tank runs out of gas.
You can start by getting a high-quality tank. An ideal industrial size would be around 300 cf, but a more manageable size is this 80 cf tank (Amazon).
Make sure the tank has adjustable dials so you can set your flow rate to your desired scale. Keep in mind this will also allow you to adjust the quality of your weld.
Make sure your TIG welding power supplies have adjustable pre-flow and post-flow settings and modify these as necessary. Most industrial models will come with a preset 20 second post-flow cool-down period, which is going to eat up your gas and significantly reduce the lifespan of your tank.
Finally, look for high-quality tanks. You can find some cheap options, but they are not worth the hassle, and you will end up losing more money than you will save.