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Gas Vs Gasless Mig Welding

Wednesday, 18th March 2020
Graham (Tech Advisor)
The Welders Warehouse Online Shop

Gas vs Gasless Mig Welding, which is best? is a conversation I have with customers on the phone on an almost daily basis.

Gasless Mig Wire

Firstly, let me clarify that “Gasless” Mig is not actually gasless.  There’s no such thing as gasless mig welding.  The weld pool has to be protected from the oxygen in the air and this is done by displacing the air with gas!

So called “Gasless” Mig Wire is actually “Self Shielding”.

Self Shielding Mig Wire is a tube of metal with a flux core.  

As the welding arc melts the wire it also burns the flux, this produces a gas shield around the welding process.  So NOT “Gasless”.

The term “Gasless” comes from the fact that Self Shielding Wires do not require a Cylinder of Gas.

Secondly, I’m going to put my cards on the table!  I’m not the Worlds biggest fan of Self Shielding Mig Wire!

OK so it has its uses, but it produces a fierce arc that’s not much use on steel thinner than around 1.2mm.

As for car body welding, if a supplier tells you their machine can weld car body thickness steel without gas GET THEM TO DEMO IT!!!

Self Shielding Mig Wires also produce a LOT of nasty smoke, so are best used in the open air.  And that really is the only place I would advocate using self shielding wire.  Even then, I would only use Self Shielding Wire when its too windy to use solid wire and gas!

A Little Bit of History

Self shielding mig wires were first developed in the USA for use on the vast prairie farms of the mid west.  A small hand held mig welder was developed that would operate off a deep cell, 24v Tractor battery.  This welder was part of a tool kit carried by the farmer and used to carry out on the spot repairs to gates etc out in the fields.

Self shielding mig wires found their way into the UK DIY welder market in the 1980’s, before disposable gas cylinders became available.  At that time it was the only way retailers could sell Mig Welders to the DIYer.

Solid Wire + Gas

By far the most common and best way to use a Mig Welder is with solid wire and a cylinder of gas. 

With this configuration, the Mig Welder pours gas over the weld pool as you weld, thus keeping Air/Oxygen from contaminating the weld.

Solid Wire + Gas is easier to use and produces better quality welds

I’ve written a separate Blog article called:

Mig Welding Gas which you may find useful

Bottom Line

In my opinion, if you have a Gas/No Gas Mig Welder you should always use it with Gas, unless you absolutely have to use self shielding wire.

I personally, would prefer to protect the work area from wind with screens etc than use self shielding wire, but as I said earlier, I’m not a fan ?

We offer a full range of Mig Welding Wires for most materials, including Solid and Self Shielding wires for steel.

Can any Mig be used for Gas AND Gasless Welding?

No, a Mig Welder will be designed to either use Wire with Gas, Self Shielding (gasless) Wire, or both (Gas/No Gas).

The difference lies in the Polarity of the Torch.

To use Self Shielding (Gasless) wire, the Torch needs to be NEGATIVE (-).

To use Solid Wire with Gas the Torch needs to be POSITIVE (+).

A machine that can operate with both Solid Wire + Gas AND Self Shielding (gases) wire will have a way of quickly and easily changing the Polarity.  These machines are normally marketed as “Gas/No Gas” Mig Welders.


Gas vs Gasless Mig Welding, which is best?  Well I think you know my answer to this, Gas, almost every time! 🙂

Visit our Mig Welders Page to view our current range.

Need to Know More?

If you’re not sure what type of Mig Welder would best suit your needs, get in touch, you can write via our Contact Us page, or phone and ask for me! (numbers at the top of this page)

I hope you found this useful.

Please let me know what you thought of this article by leaving a comment.  Don’t worry, your email address won’t be added to a database or shared and you won’t receive any unsolicited email.



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