Welding gas is an important component of MIG and TIG. While you can attempt to MIG without it, the quality of the final result is just not as good. And in the case of TIG, gasless welding is not at all possible. When it comes to sizes, there are many different options, although the most common and best welding gas bottle and cylinder sizes are the 40, 80 & 125 cu/ft ones. Below, we’ll share some of the best options available to you.
Unbeknownst to many, choosing what gas to use is not limited to selecting which one is suitable for your chosen workpiece. You also need to consider other aspects, such as the right settings when using for MIG and TIG and the cylinder sizes suitable for your workshop. Here’s everything you need to know about welding gas bottle sizes.
Best welding gas tanks & bottle sizes
We have carefully researched the market to find the best gas welding gas tanks for your purposes. Check them out below!
At a loss about all these? You don’t have to. You just need to keep reading to find out more, as well as learn some tips that can prove handy for all your projects. We will walk you through all the different aspects that are important to you, and then we will be sure to leave you knowing a lot more about the topic as you are done reading this article.
It’s important to know that there are different kinds, and different ways for each to be used. Each of the different types has its own set of functions that it is trying to achieve.
When we talk about gases in welding, most people would immediately think of the shielding one. What they don’t realize is that there are actually different types used. There are also ones used to clean the welds formed or protect the materials after the bond has been made.
Some metals or filler rods require preheating before welding to ensure a final quality product or brazing. For this purpose, you need to use heating gas. This type is typically a mix of fuel gas with some oxygen added and when it is lit up, it gets warm enough to heat, but not melt, the materials. Read on in order to learn more about the individual types.
To prevent the contamination of the molten pool when doing MIG or TIG, which results in an ugly end result, you need to use a shielding option. This type is important because it not only affects the appearance but also the bead shape and penetration, alloy content, fumes produced, and many others.
Shielding gases are often inert ones and can either be pure, which is made up of a single type , or a mix of different types. The pure options are argon, carbon dioxide, and helium, while the mixtures used as shielding option can include different combinations of pure options or adding oxygen, nitrogen, or hydrogen to them.
Among all the pure choices, argon is the most widely used shielding option because it is inert and will not cause a reaction to the metals being worked on. Because of this, it is suitable for working on aluminum, as well as for other metals that are refractory or reactive. You can use this with all types of materials in TIG, while its use in MIG is limited to nonferrous materials.
Argon also causes a low heat transfer because both its ionization potential and thermal conductivity are low, creating the deep and narrow penetration it is known for. Not only that, but you also get a very stable arc that allows you to have better control over the pool that is created. Also, argon aids in the breaking down of any oxides present in the workpiece.
In contrast, helium is known for having high ionization potential and thermal conductivity that results in a deep but wider weld and increased heat. Unfortunately, it also makes starting the arc much more difficult, especially if you do not use the correct settings of your MIG or TIG. This type is not commonly used in MIG and is only suitable for nonferrous metals when using it for TIG.
Carbon dioxide is normally only used for MIG, as well as the highly-similar flux core method, because it has complex interactions with different metals. With this type, you get a balanced ratio in terms of depth and width due to its wide penetration and high heat. This increased heat is also because of its low thermal conductivity and ionization potential.
Using different shielding mixtures is a common practice. In fact, these mixtures even work better with certain metals compared to using pure gases. Found below are the different metals and recommended mixtures to be used:
- Carbon steel – argon and carbon dioxide, argon and oxygen, argon, carbon dioxide, and oxygen
- Stainless steel – argon and carbon dioxide, argon, carbon dioxide, and helium (aka tri-mix), nitrogen and hydrogen (only for austenitic stainless steel)
- Aluminum – argon and helium, tri-mix
- Light gauge steel – argon and oxygen
- Nickel – argon and helium
- Copper – argon and helium
A common issue is that craftsmen take strides to ensure a neat final result on the surface but neglect the underside. Because of this, the underside looks different and can even be contaminated because it is unprotected by any shielding gas.
To address all these, doing a back purge is necessary for a clean weld on both the surface and its underside. When back purging, a purging gas that acts like a shielding mechanism is used for the underside. This process is usually done when working on stainless steel, as well as nickel and titanium alloys.
Carbon dioxide and nitrogen are often used for purging purposes , but you can also use other inert options like helium and argon.
In instances where you need to ensure that your finished product must be completely flaw-free, a shielding option may not be enough to prevent contamination. As the metal cools, it can still be stained or damaged by any contaminants present in the atmosphere. Using a blanketing gas, often nitrogen, will protect your workpiece from these contaminants.
Shielding ones are the ones used most often, but it is also important to familiarize yourself with the other types you can use for your projects.
Bottle, Tank & Cylinder Sizes
A welding gas is typically not flammable but it still poses some health risks, that is why you need to choose the right cylinder size for your workshop. Not only that, but it will also provide convenience for you because you don’t have to keep getting a new one when you run out.
High-pressure welding tanks, namely oxygen, helium, nitrogen, hydrogen, and carbon dioxide, use cylinders with uniform sizes. A high-pressure cylinder, also called a bottle or tank, typically has volumes ranging from 20 to 300 cubic feet. Bottle sizes are indicated either by their volume or represented by letters, such as:
- R = 20 standard cubic foot or scf
- V = 40 scf
- Q = 80 scf
- D = 125 scf
- S = 150 scf
- K = 200 scf
- T = 300 scf
Note that the welding bottle sizes above apply for those encased in steel cylinders. There are also aluminum cylinders available, but they have much more limited sizes.
Low-pressure options, on the other hand, have more varied sizes.
When it comes to doing this type of work, argon is arguably considered as the most important gas. Different types use different amounts of argon, as well as other gases, so you need to know which tanks to use for your project.
The problem lies in the fact that, with the exception of high-pressure bottles, many of the tanks used come in different sizes depending on the manufacturer. This is purposely done by manufacturers so that they can easily identify which tanks are theirs.
Despite this, they also make tanks in sizes that can be considered common to different manufacturers. For example, argon has the following common bottle & tank sizes that are represented either by a letter or number, ranging from 21 to 335 cubic feet:
- R or 20 = 21 cubic feet
- RR or 40 = 44 cubic feet
- Q1 or 60 = 65 cubic feet
- Q or 80 = 83 cubic feet
- S or 125 = 125 cubic feet
- S or 150 = 155 cubic feet
- K or 250 = 251 cubic feet
- T or 330 = 335 cubic feet
Note that the S-sized tanks have two types available, that is why it is important for you to check the actual volume when purchasing this type of tank. And in most cases, the smallest-sized tank allows you to work continuously for an average of 1 hour to 1 hour and a half.
Settings for MIG and TIG
Aside from choosing which option to use and the right bottle size you need, you also need to determine the right settings for MIG and TIG.
Using gases is not as simple as letting them flow freely as you work. You need to make sure that just the right amount is being released because this will also affect quality of the metal bond. Both MIG and TIG have uniform settings regardless of the type of shielding gas.
When it comes to MIG , the flow rate typically ranges from 25 to 30 cubic foot hours (CFH) and its matching pressure should be between 3 to 7 psi. Most craftsmen consider 20 CFH as an ideal flow rate, since setting it higher increases spattering and also makes the weld porous. Note that bigger nozzle diameters, as well as drafty conditions, will require higher gas flows.
The flow rate of TIG, on the other hand, is typically lower than that of MIG and ranges from 15 to 25 CFH on average. However, it can also go up to 50 CFH if you use larger cup sizes. If your flow rate is between 35 to 50 CFH, the pressure should be between 20 to 30 psi to match it. But if you have a lower flow rate, you also need to lower the psi.
MIG and TIG both require the flow rate and pressure to be directly proportional. That is, the higher the flow rate, the higher the required pressure. They only differ in the actual numbers.
These different types are extremely helpful when working, but using them is not as straightforward as some would think. Whether it’s your first time to using it when welding or you have already tried it but have yet to get satisfactory results, these tips are sure to help you out.
- Use a lens if you want the flow of shielding gas to be evenly distributed and lessen defects caused by contamination
- If you want a laminar flow, opt for a converging nozzle with the longest length and largest diameter suitable for your project
- To get the best results, you should do a pre-flow and post-flow
- Don’t ignore any leaks. Not only will it contaminate your work, but you also end up wasting gasand money because of it
- Back purging is the best way to prevent sugaring or oxidation on the underside of your workpiece
- For aluminum work, lessen the gas if you are welding on A/C
- When working on sheet metal, opt for an option with a higher argon content for less spatter
- Use a tri-mix option consisting of 90% helium, 8% argon, and 2% carbon dioxide when MIG welding 304 and 316L stainless steel
- Test if your flow is appropriate by placing your hand around 3 inches from the nozzle tip and allow the gas to flow. If you feel the gas at this distance, it means you have an adequate flow that will prevent a porous weld
- Refer to manufacturer recommendations in terms of which option to use with equipment and workpiece. Your choice should also match your wire.
- Ensure that the shielding gas flowing out sufficiently protects the molten pool to reduce spatter
More is not necessarily better. For both MIG and TIG, you need to use the right amount for your projects. If you use more than what is necessary, it will be easier for your workpiece to be contaminated.
Did this article better help you understand what you came here to learn, or did you think there aspects related to welding gases that you would have liked for us to include? We love receiving input from our users, and often include some of their feedback into the articles. If you are interested in continuing to read, we have a couple of interesting articles on plasma cutters, and there is one on the best engine driven welders, too. Or perhaps your interest more so include learning how to actually use a plasma cutter, which we can also help you learn.
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If you don’t have the time to read the entire section above, we encourage you to read this section that will make it possible for you to get a lot of the same information, however it has been compressed here. We have also given it various different titles, making it easier for you to find the information that you are looking for. The above section does provide a more in depth review of all your various options, so you may want to take a closer look at that if you haven’t already.
If you read the above section, but you still feel like you have unanswered questions, there is a chance that reading this part may satisfy your curiosity.
Should you weld without shielding gas, or perhaps, what happens if you choose to do so?
If you don’t use the adequate amount and type, you will find your end result being porous and weak, why it is imperative that you understand the use of this material for your work. Flux-clad or flux-core arc welding can be used without the use of shield gas, but it is otherwise imperative that you use it. As you don’t want to contaminate your weld pool as you are working on it, you will want this matearial to do its job and protect the work that you are doing!
Are all gases inert, and if not which ones are?
The two options that are in fact considered to be inert are helium and argon. There are also two gases that are SEM-inert, and those include carbon dioxide and nitrogen.
Can you use any type?
The type that you are using will depend on the type of welding outcome you are trying to achieve. There are only some types that are used that include compressed air, propylene, propane, acetylene, hydron, nitrogen, helium, oxygen, carbon dioxie and argon.
If you are interested in learning more, we recommend you to read the article on oxy acetylene settings when you are using a cutting torch, which we have written an extensive article on as well.
How can I make sure that I don’t end up spending significant amounts of money on gas alone? And what is the most common type used?
We fully understand if you are concerned that you’ll be raking up a huge bill, and we do have a recommendation when it comes to that! The easiest way to keep your cost down when you are welding is by using a mixture of argon and carbon dioixide, which will both ensure that you get good results, but also ensure that you aren’t spending massive amounts of money on your projects. If you are doing a lot of welding, going with this combination, you can really save a lot of money! Because of ts price tag, the argon and carbon monoxide mixture is also the most common option that craftsmen choose!
What is a shielding gas?
A shielding gas helps maintain the quality of your welding by keeping it from becoming contaminated with the absorption of various things like hydrogen and oxygen, which can be found anywhere in the atmosphere.
Argon and carbon dioxide are the ones that are most commonly used to make sure that the final product does not become contaminated.
Best options for MIG – which one should I go with?
For metal arc, your best bet is argon as it can be used no matter the grade that you are going for! You should know that it can be mixed with other types depending on the result that someone is trying to achieve.
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