One of the most inconvenient aspects of welding with gas is lugging around a gas cylinder together with other equipment. Consequentially, many ask if it is possible to MIG weld without gas.
Technically the answer is no, however, yes, it is possible to MIG weld without gas, but you will need specific welding supplies. If you plan on doing a large welding project, you will need gas. If, on the other hand, you plan on doing a small home project or repair, MIG welding without gas may work for you and save you some money as well.
Why Gas Is Used When Welding
MIG or metal inert gas actually implies the use of gas right in the name. It normally requires a shielding gas. This is the gas that will prevent the molten welding procedure from being contaminated by or interacting with gases in the air.
Your ordinary MIG welding of mild steel makes use of the shield of inert gas so that it does not oxidize once it is melted. That said, theoretically, MIG gasless welding does not exist.
Flux Core Wire
If you normally make use of solid wire for your MIG welding, you know that it requires shielding gas to protect your weld and prevent contamination. A MIG wire that is flux-cored can permit you to weld without a gas.
The so-called “gasless” MIG procedure employs the use of the specific wire, “flux core wire”, that shields itself by turning the flux into a gas while the wire is melting This allows you to avoid using an external cylinder of gas, so the procedure is a bit simpler.
Gasless Welder Polarity
For gasless welding, set up your welder with positive earth and negative electrode. This should give more power for melting the wire.
Flux Core Wire Welding
When using flux core welding, there may be some weld spatter and a slag crust may form on top of the weld. Slag will bubble up as a protective coating and will not permit you to see the weld pool. This, unfortunately, is one of the downsides to welding without shielding gas.
When doing MIG welding with shielding gas you can adjust both speed and your technique because you are able to see the weld pool. To improve your results when welding without gas, practice on scrap metal will allow you to adjust your settings.
Some welders suggest moving your torch in a zigzag pattern with this type of wire. It should prevent any risk of your arc dipping back into a weld pool that is cooling.
Slag, in any case, should block the arc. With flux core wire welding, the arc is pretty stable, however, the slag will not conduct, so tack welds should be cleaned before you actually weld.
You can easily remove the slag crust that forms using a wire brush and the result should be pretty clean. Do not brush around the extreme edge of your weld.
Inappropriate Cored Wires for Gasless Welding
There are a couple of types of cored wire that are not appropriate for gasless welding. One is called a “dual shield” wire. It is generally used to weld very thick metals to better the toughness of the weld.
However, it does not have sufficient gasless flux to be able to shield the weld. This wire is used with shielding gas.
The other type of wire is called “metal cored”. This type of wire is filled with metals that have been ground up. This can present various properties therefore it requires the use of shielding gas when welding using it.
Advantages and Disadvantages of Gasless MIG welding using flux core
If you are learning MIG welding, using flux core wire is not all that easy. Some of the disadvantages include:
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- Not every material can be welded with this process.
- It is not ideal for welding thin metals.
- You will not be able to see what the weld pool is doing.
- Both smoke and flux can impair the visual of your welding, making it difficult to see what you are doing.
- Another consideration is that flux will not conduct electricity. This means you need to take extra care to not weld tice over the same piece of metal once it has cooled.
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Another consideration is your welding machine. You need to make sure that it will support flux core wire for gasless welding. Also, the flux core wire must be handled with care in order not to damage it before use.
Advantages of self-shielding flux core wire welding:
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- It can be used for a number of applications
- It’s a bit simpler to learn
- It’s more affordable for your wallet
- It offers easier transportability because it requires less equipment.
- You can weld outdoors in windy conditions.
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Apart from some economic savings from not having to rent a gas cylinder, the greatest advantage is to be able to weld in the presence of windy weather or wind gusts. This is an important consideration if you need to weld something outdoors.
Welding with gas shielding will struggle with even a small breeze, much less wind. The greatest advantage of flux core wire rather than using mild steel wire is that it can be used in an outdoor windy situation.
Considerations for Using an MIG Welder Without Gas
Safety is the first thing you should consider if you want to MIG weld with flux core wire. Keep in mind the risk of burns and UV damage.
This means wearing your protective equipment including safety gloves, safety goggles or glasses, a protective apron, and closed-toe shoes at the least.
While a flux-cored arc can weld dirty metal with good results, welding very clean metal will provide even better results.
Either brush or grind the metal surface that you plan on welding to remove grime or debris of any type. This will also help to remove any air that has been trapped, giving you a better weld.
Choose the correct welding machine. More power can treat thicker metals. Usually, a 115-volt welding machine or higher will be a good choice and these machines preheat well.
FAQ
Can I use an MIG welder without shielding gas?
Yes, you can use an MIG welder without gas by using a flux core wire that will create slag on top of the weld as soon as it cools. This slag will protect the weld puddle from contamination by atmospheric gas.
Is MIG welding without gas any good?
The greatest advantage to gasless welding is that it can be performed in windy conditions. It provides the same results as gas-shielded welding if done correctly.
Can I use flux core wire in my MIG welding machine?
Yes. Flux core wire is used in MIG welding machines.
Can I use gasless wire in my MIG welder?
No, MIG welding machines are designed to use wire with gas, wire with a self-shielding gas (Flux core wire, or both. The torch polarity defines the difference.
If you use a self-shielding wire (Flux Core Wire), the torch should be negative. If you are using wire with a shielding gas, your torch will need to be positive.
The Bottom Line
Because MIG stands for “metal inert gas”, technically one cannot do MIG welding without gas. The name itself implies this.
However, it is possible to weld without carrying a gas cylinder around because flux core wire has been created to form its own shielding gas right while you weld.
With the correct welding machine and supplies, you can weld without transporting a bottle of gas as the flux core wire will shield the weld for you.
