I usually weld with stick welding but have recently switched to MIG welding which gives me more control over my work. I can vary the gas mix to find the combination that works best for different projects and materials. When I saw my results, I wanted to learn more about MIG welding gases.
MIG welding gas is an essential part of the welding process. Various gases can be used for MIG welding, each with its own advantages and disadvantages. the purpose of this The gases are intended to protect the electrode and base material from atmospheric oxygen and moisture.
This guide provides an overview of common welding gases: argon, helium, carbon dioxide and oxygen. Understanding the pros and cons of each gas will help you choose the right one for your project.
Content
Why is a gas used in MIG welding?
Before we continue, let's be clear that there is no such thing as "gasless" MIG welding (MIG stands for Metal InertGas). Below, we compare MIG with Flux Cored Wire Arc Welding (FCAW), which is technically not gasless but does not have an external source of gas.
The main purpose of using gas in MIG welding is to protect the weld pool from oxidation, water vapor and contamination. Gases such as hydrogen and nitrogen can affect the quality and texture of the work. They are absorbed by the molten metal, and when the metal freezes, they are trapped as voids.
Gas welding uses a solid wire and a "shielding gas" (usually Argon-CO2mixture, although other gases are also used). A gas tank supplies the shielding gas and releases it through a nozzle.
Without an external shielding gas, you will have to replace your solid wire coil with a tubular wire coil. These wires generate their own shielding gases when they melt, which is why they are also known as self-shielding (this process is known as flux-core arc wielding, or FCAW).
MIG welding has less smoke.
When using a MIG welder, the welder emits shielding gases such as argon and CO2(Note that the CO2is a semi-inert gas) to prevent the hot wire and base metal from coming into contact with atmospheric oxygen to prevent combustion and oxidation.
In contrast, gasless welding uses flux-cored wire. This is a yarn with a cleaning agent called "Flux" in the middle. The flux is melted during the soldering process, releasing gases and liquid slag that prevent the base metal from oxidizing.
These gases, along with vapors from consumables and base metals, consist of metal particles and small amounts of carbon monoxide. They can cause short-term effects such as nausea and drowsiness andserious long-term effectssuch as lung damage and cancer when inhaled regularly.
Therefore, it is highly recommended to use a respirator when welding without gas and ensure good ventilation or a fan. These gases also interfere with the visibility of the weld pool.
Fumes can also contaminate the metal you are working with. However, you can easily clean the bumps with a spray or a cloth.
Although MIG welding produces less smoke, it still produces certain harmful gases such as nitrogen dioxide and ozone. Ozone is colorless and odorless and is not filtered by a respirator. Therefore, a ventilation system is still necessary in MIG welding.
MIG does not produce dross (typical) and produces less spatter.
Slag is a coating that forms on your weld. It mainly consists of chemical compounds and other materials such as oxides, but it may also contain quartz sand. The presence of slag in your weld can be identified as an elongated crust that is either continuous or discontinuous along the length of the weld.
Generally protected against gassun day MEdoes not include filler wire. With FCAW, this slag splatters onto the base metal with each weld, solidifies, and must be cleaned with a wire brush, chipping hammer, or emery.
Spatter refers to droplets of molten metal that splatter in all directions and solidify during welding. While it is difficult to completely eliminate spatter, shielded gas arc welding generally produces less spatter. In comparison, using a tubular wire generates more spatter due to flow. Spills can be removed with hand tools or anti-spill spray.
In this regard, the use of gas in welding makes the work less dirty, less time-consuming and does not require additional cleaning work.
Exotic metals cannot be welded without gas.
Every now and then, if you've been soldering long enough, you'll come across someone selling flux-cored wire that claims to weld aluminum or other exotic metals. Although some laboratory fluxes can weld aluminum, they require extreme care in handling and storage and are basically impractical for general use.
Aluminum is soft and highly sensitive, so when molten it is very reactive to atmospheric gases and contaminants. It also doesn't visibly glow when it heats up, making it difficult to determine the condition of your solder.
ComArc welding with cored wire(FCAW), the gases released from the flux are less reactive than aluminum and do not provide effective protection for your solder. In addition, cast aluminum absorbs hydrogen and moisture very quickly. You'll likely end up with an overly porous solder that doesn't hold very tight.
Soldering aluminum with FCAW can result in scorching, porosity, or pooling of solder falling onto the workpiece unless you are extremely careful with voltage, wire speed, travel speed, and the type of flux used.
Therefore, to melt aluminum safely, MIG orTIG weldingit's the way to go. However, you cannot use CO2as a shielding gas, as molten aluminum is more reactive than CO2. You would need to use 100% argon or, for aluminum larger than 0.5 inch, an argon-helium mixture.
What gas do you use for MIG welding?
There are several gases that you can use with yourMIG welder. Carbon Dioxide (CO2) and argon are the most popular gases. Small percentages of oxygen and helium are also used for certain solders.
For most commercial solders, you would use a mixture called C25, which contains 25% carbon and 75% argon. Welding gases are stored in high pressure cylinders. You can buyC25 bottlesfrom your local welding shop and evenorder them online from Amazon.
80 cu/ft 75% Argon 25% CO2 Weld Tank Cylinder CGA 580 - COMPLETE
- All HP cylinders come with a 10 year hydrostatic test date.
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Product prices and availability are correct at the date/time shown and are subject to change. All pricing and availability information displayed on [Relevant Amazon Sites] at the time of purchase is for the purchase of this product.
argon
Argon is usually mixed with CO2or other gases, but is often used independently. It is one of the chemically "noble" or inert gases. This means that it has very little tendency to react with the atmosphere or the base metal.
The use of argon provides a narrower penetration profile and helps maintain a stable arc angle. Pure argon gas is used to weld non-ferrous metals such as aluminum, titanium or copper.
carbon dioxide
Reines CO2as a shielding gas it is a popular choice for many MIG welders. It is the only gas that works without the addition of inert gas and is relatively inexpensive.
CO2MIG welding offers a deep penetration profile, a hot arc and is suitable for thick materials. However, this generates more spatter and the arc is not as stable as with an argon-carbon mixture. 100% CO2only allows short-circuit transmission.
oxygen
Oxygen is often used in less than 1/10ºto improve penetration, maintain good wetting (i.e. increase weld pool fluidity) and harden the arc. It is used in spray overlay welding of alloys and stainless steels.
However, it can form dross and should not be used with reactive alloys such as copper and aluminum. Excessive oxygen consumption can cause oxidation of the MIG electrode, resulting in more holes in the weld pool.
Even though we all look at oxygen the same way, that's not necessarily true. Ooxygen cylindersYou see the purest form of oxygen in hospitals, which is not of the same quality as what is used for soldering.
Helium
Helium is another inert gas commonly mixed with 25-75% argon. It is used for wider and deeper penetration and for welding stainless steel or non-ferrous metals such as aluminum. It has a high flow rate, which means the cylinder will empty faster.
Helium requires a higher voltage and creates a high-energy hot arc. It is often used in small amounts in a "Tri-Mix" mixture to adjust arc characteristics, penetration profile and prevent oxidation. Helium is added to pure argon when welding exotic metals greater than 0.5 inch thick.
What is the best mixture of argon and carbon for MIG welding? (What gas mixture is used to weld sheet metal?)
The exact argon-carbon mixture depends on the metal you are working with and the type of solder joint you prefer. I usually work with C25, but I can do most of my work with pure CO2when I run out of C25.
The most common mix for MIG welding is C25 (75% Argon and 25% Argon). C25 only allows short circuiting and spherical metal transfer. For the average amateur, this method offers the best value for money.
- More argon generally means tighter and reduced penetration. May be preferred for fillet and butt welding. However, if you are welding stainless steel, for example, you want a lower argon to CO2 ratio.
The use of argon helps to stabilize the arc and produce less spatter. Argon's inertness makes it desirable for reactive metals such as aluminum and magnesium. When working with soft metals, you generally want an argon mix. Pure argon is not commonly used for welding.
- The CO2 contributes to deeper penetration and increases the heat and energy of the arc. Since CO2 is not inert, it does not prevent oxidation as effectively as argon or helium. It also generates a noticeable amount of splash.
You can also go with 100% CO2 seThey won't work on thin or exotic metals like aluminum. The arc is less stable than if you mixed an inert gas and there is more cleaning to do after each weld.
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The C50 mixture (50% Argon and 50% CO2)it's not as wet as the C25 and the solder tends to stick where you applied it. C50 is widely used for short arc welding of pipes, especially when the surface contains contamination.
By increasing the proportion of argon in an argon-carbon mixture to 80% or more, you improve weld penetration and reduce spatter (thus increasing deposition rate). You can use all four transmission modes even with such a high argon ratio.
If you intend to weld sheet metal, it is best to use an argon-based mixture (ie at least 75% argon) - the higher the argon content, the less heat and spatter.
C15 (85% Argon and 15% CO2)is popular with many companies working with structural and carbon steel. If you are working with thick metals (approx. 0.5 cm) or prefer to weld mill scale, the C15 is suitable.
The C15 also supports all four metal transmission modes. By switching between transfer modes, you can weld both thin and thick metal parts. However, due to 85% argon, wetting can be stronger, although with practice you can get better control of the weld pool.
C15 short circuit transfer works well when welding sheet metal and there is less chance of burning than CO2misturas made from
If you want to go for aesthetics, you can use aC10 mixture (90% Argon and 10% CO2).The resulting weld is smoother and flatter with less spatter to clean up.
The penetrating power of C10 is good, but less than that of C15 or C25. C10 is good for spray transfer and generally not good for short circuit transfer with many welders.
The bow becomes less energetic as you move downC5 (95% Argon and 5% CO2). One of the main benefits of the C5 is that it allows for good impulse spray transfer. It is suitable for welding through lamination flakes. However, if you've never used it before, you'll need to get used to the puddle control.
Compound C5 can also be used for short circuit transfer, although you must carefully adjust the welding parameters so that the heat released is not too low.
MIG welding gas prices
Gas prices depend on bottle size, type of gas and where you live. A 40, 80, or 125 cubic foot (CF) cylinder is sufficient for most home welders.
Noble gases like argon and helium are more expensive than CO2or oxygen. You can expect to pay between $150 and $350 the first time you buy a full bottle. Top-up packs are usually much cheaper. Refilling a 125 CF cylinder can cost as much as $40 for pure argon, $30 for C25, and $20 for oxygen.
| Volume (CF) | average Cost of an empty bottle |
|---|---|
| 20 | $ 110 |
| 40 | $ 140 |
| 80 | $ 200 |
| 125 | $ 235 |
Diploma
There are several welding gas mixtures available on the market. Each combination results in a unique penetration profile and transmission mode. In general, carbon dioxide and argon are used independently or mixed together, sometimes with helium or additional oxygen. MIG welding gases produce less smoke and spatter than traditional welding.
Below is a helpful YouTube video on gas welding for beginners.
More reviews about welding machines
Welding hazards and safety precautions
Arc and MIG welding, what's the difference?
Welding Safety Checklist: A Guide to Safe Welding
Top 5 Welding Carts with Reviews and a Buyer's Guide
FAQs
What is the most common mistake when MIG welding? ›
Porosity, one of the most common MIG welding defects, is the result of gas becoming trapped in the weld metal. Inadequate shielding gas coverage is among the biggest culprits, and this can be addressed in several ways.
What is the hardest welding process to learn? ›TIG welding is the hardest form of welding to learn for a variety of reasons. The process of TIG welding is slow and takes time to get used to as a beginner. A TIG welder requires a foot pedal to feed the electrode and control the variable amperage while maintaining a steady hand at the welding torch.
What is the number 1 rule in welding? ›Weld from the bottom up.
Like building a house, you cannot start the bricks at the top. Weld metal is a liquid. When it goes in it needs support, that is why we need to always start at the bottom.
There are a couple shielding gas options for MIG welding gas, depending on your application and needs: A 75 percent argon/25 percent carbon dioxide blend (also called 75/25 or C25) works as the best all purpose shielding gas for carbon steel.
Why doesn't my MIG weld penetrate the metal? ›Excessive heat input is usually to blame for the problem. To correct this, select a lower voltage range, reduce the wire feed speed and increase your travel speed. Conversely, insufficient heat input can cause lack of penetration, or the shallow fusion between the weld metal and the base metal.
Can you have too much gas when MIG welding? ›Operating with an excessive gas flow rate can cause turbulence to occur at the base of the welding gas nozzle. Turbulence means air gets sucked into the flow of welding gas. This can result in the appearance of porosity, inclusions, and spatter – all the issues that welding gas is meant to prevent in the first place!
What is the hardest position to weld in? ›Overhead
The overhead position weld is the most difficult position to work in. The welding will be performed with the two pieces of metal above the welder, and the welder will have to angle him or herself and the equipment to reach the joints.
TIG welding is often considered the strongest weld since it produces extreme heat, and the slow cooling rate results in high tensile strength and ductility. MIG is also an excellent candidate for the strongest type of weld because it can create a strong joint.
What type of welding pays the most? ›The highest paying welder jobs are in industrial construction. Pipe welders, tube welders, rig welders, underwater welders and combo welders are the highest paid of all welding jobs. The type of welding is important and so is the industry. The top welder salary can be over $200,000 per year in industrial construction.
What is the golden rule in welding? ›1. Joint preparation is critical. 2. Comfort is more important than welding technique.
What does 135 mean in welding? ›
135 metal active gas welding (MAG welding); 136 tubular cored metal arc welding with active gas shield; 141 tungsten inert gas arc welding (TIG welding);
What PSI should MIG gas pressure be set at? ›The ideal pressure range for most standard MIG welding jobs is between 3 to 8 PSI.
Do you push or pull when welding? ›Push or pull: Here the rule is simple. “If it produces slag, you drag,” says Leisner. In other words, you drag the rod or wire when welding with a stick or flux-core wire welder. Otherwise, you push the wire with metal inert gas (MIG) welding.
Can you run 100% argon on MIG? ›The most common gas used for MIG welding aluminum is 100% argon. This gas allows you to get into a spray transfer or pulsed spray transfer mode easily for aluminum due to its low ionization value. Another benefit of 100% argon gas is that it can also be used for TIG welding aluminum.
What voltage should a MIG welder be set at? ›The voltage and wire feed speed vary though. A 0.024-inch wire would operate at 13 to 15 volts (electrode positive) with a wire feed speed of 130 to 160 ipm, whereas the 0.30-inch solid wire would require 15 to 17 volts and 75 to 100 ipm wire feed speed.
Do you push or pull sheet metal when MIG welding? ›The everlasting discussion is whether to use the pull or push technique with MIG welding. Pushing is a better choice with sheet metal, as it allows a better view and control of the weld pool and lower penetration than pulling.
Why does my MIG welder splatter so much? ›Welder settings differ between TIG and MIG welding, with MIG techniques requiring the wire feed to be at the correct speed. If it is too fast, the metal wire will hit the molten pool and cause it to splash and spatter, but if it is too slow and the wire is vaporised before it reaches the weld, there will be spatter.
Why are my MIG welds bubbling? ›The further away the gun is from the weld site, the more likely air and gas will seep into the weld puddle causing bubbles to form which will in turn make a weak weld. Preventing porosity in your weld will overall increase the durability and purity of your weld.
What is the most common causes of excessive spatter during MIG welding? ›Dirty or Contaminated Metal Surface
Dust, oil, grease, and marker pen lines are some common contaminants that cause the molten metal to spit and spatter. Sometimes, metals also have protective coatings that aren't designed for welding, so they increase the amount of weld spatter.
An edge joint is the weakest type of weld join, so isn't suitable for load-bearing jobs. Instead, it's ideal for reinforcing metal and replacing worn and damaged metal.
What is the easiest metal to gas weld? ›
- Mild Steel. Mild steel is a metal which contains low amounts of carbon and is predominantly made up of iron. ...
- Stainless Steel. ...
- Nickel. ...
- Aluminium. ...
- Bronze. ...
- Copper. ...
- Cast Iron. ...
- Galvanised Metal.
A weld that is too small or too short for the application can fail from tension, compression, bending or torsional loads. If a weld is made to be in an application where a cyclical load is going to be applied, it will be beneficial to consider a filler metal option with increased impact toughness and ductility.
Is a bigger weld stronger? ›The strength of the weld is determined by the filler metal used and its effective area. The effective area of a weld is determined by multiplying the length of the weld times the throat. So the bigger the throat the larger the effective area and thus the stronger the weld.
Is MIG stronger than stick? ›Stick welding produces stronger welds than MIG welding as it can better penetrate thicker metals and dirty surfaces.
Do welders make $100 an hour? ›Depending on the job they undertake, they can make up to $120 per hour if it's difficult to complete. Some jobs may require the welder to be at sea for 30 days. Education requirements: A high school diploma and GED is required, along with two to five years of experience with welding on land.
What state pays welders the most? ›Alaska. The highest-paying state for welders is Alaska. The welding professionals working in Alaska have an annual salary of $70,000. The high salaries in Alaska are due to the state's vital oil and gas industry, which requires many skilled welding professionals.
What is the highest hourly pay for a welder? ›| Annual Salary | Hourly Wage | |
|---|---|---|
| Top Earners | $51,500 | $25 |
| 75th Percentile | $44,500 | $21 |
| Average | $39,931 | $19 |
| 25th Percentile | $34,000 | $16 |
The rule of thumb assumes you need to achieve full strength. This means that exceeding the size specified would increase weld strength, but not the connection strength. Meaning welding anything bigger would be total waste with no added benefits.
What is the cardinal sin of welding? ›Undercut. One is undercut, which is the cardinal sin. That's where you cut into the steel and don't replace it with filler metal. This can result in longitudinal cracks that can cause the weld to fail.
What is the welder formula? ›the width of the weld cap, w, is given by w = 2(tan b x (t-r)) + g +2r. the area of the excess weld metal is given by the formula (w x h)/2. the area 'A' is (t-r) x (2r +g).
What should welders avoid? ›
Always keep the hands and the body dry during a welding operation. Avoid standing in water, on wet surfaces, or working with wet hands or wearing sweaty garments.
Can you weld over a weld? ›It should be remembered that welding over weld metal is actually a very common occurrence. Multi-pass welds after all are manufactured by welding over weld metal! There are also many accepted procedures in which welds overlap.
What does 3 F mean in welding? ›Vertical Position (3F or 3G)
In vertical position welding, the axis of the weld is approximately vertical. When welding is done on a vertical surface, the molten metal tends to run downward and pile up.
Filler Metals: The F Number
This number is used to group filler metals used in welding procedures and welder performance qualifications.
F stands for fillet weld, while G is a groove weld. A fillet weld joins together two pieces of metal that are perpendicular or at an angle. A groove weld is made in a groove between workpieces or between workpiece edges. Using this system, a 2G weld is a groove weld in the horizontal position.
What is the correct gas flow for MIG? ›Typically for MIG welding, 15-20 l/min will suffice and for TIG welding 6-10 l/min. Your welding application – typically, manual tasks need a lower flow rate, while automated or mechanised work requires a higher flow.
How many PSI is a full MIG tank? ›But when an Argon of Argon/CO2 tank is full, it should read near the maximum pressure (which is 2015 psi most times). As you use gas, the pressure will drop accordingly. Some examples, as you use gas to weld, you will have ¾ of a tank left when the pressure reads about 1500 psi. At ½ full, it will read around 1000 psi.
What is MIG welding gas called? ›The basic gas for MIG/MAG welding is argon (Ar). Helium (He) can be added to increase penetration and fluidity of the weld pool. Argon or argon/helium mixtures can be used for welding all grades.
What is the hardest thing to do in welding? ›TIG welding is the hardest form of welding to learn for a variety of reasons. The process of TIG welding is slow and takes time to get used to as a beginner. A TIG welder requires a foot pedal to feed the electrode and control the variable amperage while maintaining a steady hand at the welding torch.
What is the main rule of welding? ›Be sure the welder is properly installed and grounded. Never weld without adequate ventilation. Take proper precautions to prevent fires. Protect your entire body with fire retardant clothing, shoes, and gloves.
What is the easiest welding to learn? ›
MIG Welding (Beginner)
MIG welders are among the best type for beginners, as they're designed with a wire welding electrode on a spool that is fed at a pre-selected speed through a welding gun. As a semi-automatic or automatic process, gas metal arc welding (GMAW or MIG), is the easiest to learn.
Choose the right gas: Because aluminum is a non-ferrous metal, it requires a 100 percent argon shielding gas.
What is the best gas mix for MIG welding? ›MIG Gases. If you're going to be MIG welding, there are two main gases that are used: pure argon and an argon/carbon dioxide mix. The most common (and recommended) Ar/CO2 mix is a 75/25 ratio, with 75% of it being argon and 25% of it being CO2.
What should I set my argon on my MIG welder? ›Gas for MIG welding mild steel
A 75 percent argon/25 percent carbon dioxide blend (also called 75/25 or C25) works as the best all purpose shielding gas for carbon steel.
When the wire feed speed is too fast, it can cause the wire to pile up instead of melting properly into the weld pool. This can also cause burnback or birdnesting. A wire feed speed that is too slow doesn't feed the weld pool, so there is not proper penetration for a quality weld.
What are 3 defects associated to MIG welding? ›Typical weld defects found in MIG welding are lack of fusion and penetration, craters and cracks, undercut, burn-through, and porosity in the weld metal.
What are the worst mistakes in welding? ›- Improper Machine Setup. ...
- Bad Cables or Connections. ...
- Improper Gas Flow or Pressure. ...
- Overlooking Preventative Maintenance. ...
- Too Much Anti-Spatter.
Welding in the overhead position—with the workpiece directly above the welder—is widely thought to be the most difficult welding position. Pipe welding is also well known to be particularly challenging welding work.
Why are my MIG welds so high? ›Q: Why are my welds ropey? A: Ropey welds — welds that are too convex and high— typically occur when welding with too high of wire feed speed and too low of voltage. This is particularly true in the flat and horizontal position. Increase the welding voltage and/or decrease wire feed speed to remedy the problem.
What does a bad welding job look like? ›Materials: Typically used on stainless steel and non-ferrous metals such as aluminum, magnesium, and copper alloys. Signs of a bad weld include: Burnout, no filler metal used, wide flat bead without distinct bead pattern, erratic beads, tungsten inclusion, porosity and/or undercutting.
Which metal Cannot be welded in MIG welding? ›
Some examples of material combinations that cannot be fusion welded successfully are aluminum and steel (carbon or stainless steel), aluminum and copper, and titanium and steel. Nothing can be done to alter their metallurgical properties.
How far away from the metal should you be when MIG welding? ›For wire (flux-core or MIG) welding, keep a work distance of ⅜ to ½ inch. With stick welding, look to keep that distance ⅛ inch between the rod tip and work piece.
What is a bad weld called? ›Bubble Gum: A poor quality weld that looks like chewed bubble gum. Busted Out: Failed a weld test.
What is the most severe welding defect? ›Weld Crack. The most serious type of welding defect is a weld crack and it's not accepted almost by all standards in the industry. It can appear on the surface, in the weld metal or the area affected by the intense heat.
Why do I keep blowing holes when stick welding? ›This means that once the weld pool has developed the wire is then dipping into a liquid. If this then becomes too runny, the dipping of the wire creates a popping effect much like a needle popping a balloon, and this can pop it causing a hole.
Is it unhealthy to be a welder? ›Both acute and chronic health risks are associated with welding fume. Occupational lung disease, including lung cancer, is the most common health risk, but welding can also affect the eyes and skin.
What is the pressure setting for gas welding? ›The adjustment of the pressure of the oxygen bottle must be set between 0.8 and 1.5 bar. The one for the acetylene bottle needs to be between 0.3 and 0.5 bar. You will then open the valves of your blowtorch. This adjustment will lower the pressure that you will need to readjust before welding.