You could use either for mig welding, but which one is
best suited to you application. Here we explain some of the differences between the two mig welding wires.
Which one should I use?
Now first up the gasless mig wire. Without a doubt the flux core mig wires are most commonly used for the DIY
welders and home handymen. Go here to see what a gasless mig welder
is.
They are also used by the professional welding businesses for various reasons too. We are talking about the use of
E71T-GS gasless wire here, there are other flux cored wires but they will need to use a shielding gas with them as
well.
These other flux cored wires might also be referred to as "dual shield" flux core wire. Or gas assisted flux core
welding wire.
Why would you want to use a gasless flux cored mig wire? Firstly because it will allow you to weld without the
normally associated bottle of shielding gas that is commonly used with the mig welding process.
By not having to use a shielding gas you will straight away save both monthly rental on a gas bottles and you will
save money by not having to use the actual gas in the bottle.
Gas company's make an awful lot of money out of supplying welding gases to end users. By simply using a self
shielding mig wire you can save these ongoing costs.
One of the main reasons the professional tradesmen will use gasless wire is because for onsite work that requires
only a few welds to be performed, the worker needs only to carry a small mig welder and a spool of gasless wire and
away he goes. There is no need to lug around a big gas bottle to the worksite as well.
Once again this is also the big seller for the DIY welder. Usually the average person only needs to weld every now
and then. Using gasless wire will save those gas costs.
Another major benefit of gasless mig wire is that you can use it outdoors in windy conditions. Unlike gas assisted
solid wires where the wind will blow away the shielding gas. The gasless wire has a flux that is manufactured
inside the core of the wire.
This flux is what provides the required shielding gases needed to weld. Gasless mig wire is much like a welding
electrode in that it uses a flux to create the shielding gases that are needed to make successful welds. A welding
electrode has its flux on the outside of the filler material, where as your gasless wire has the flux on the inside
of the filler material. The mig wire is much smaller compared to that of a welding electrode as well.
In comparison an average sized or commonly used size of welding electrode or welding rod is 3.2mm (1/8") in
diameter and an average sized diameter of mig welding wire for both gasless and solid wires is 0.9mm (0.035").
Showing most common size mig wire and electrode diameter for comparison.
Gasless mig welding wire produces a reasonable quality weld bead but the down side is that you get a lot of smoke
and spatter. This smoke can be very bad to your health if inhaled for long periods of time. It is highly
recommended that you use a welding breathing mask to filter out the smoke.
After the completion of a gasless weld there will also be a covering of slag over the weld bead. Compared to the
slag covering that is produced from a welding electrode, the gasless weld bead slag covering is very minimal. It is
extremely easy to remove as can be seen in the video below.
The weld bead in the below video is not very good. I have included some other photos so that you can have
a better idea of how good a weld bead you can actually get when using a gasless mig welder and E71T-GS wire.
Gasless mig welder welding video 1
This video below shows me welding the welds that are in the abouve pictures. The
parts that are being welded are pallet racking shelves. I needed to make them shorter to so they
would fit where they had to go.
Notice how the finished welds are nice and smooth, even, and have a good shaped profile to the
weld beads.
Listen to how the machine sounds when welding with this Kiswel K-NGS gasless mig wire so
that you can get an idea of how it should sound when you are mig welding. The welds done in this
video were with a small home mig welder type machine.
Gasless mig welder welding video 2
The weld bead in the below video is not very good. But it is showing how easy the slag is to
remove as compared to a welding electrode weld. The slag is much thinner.
Using the back of a wooden welding brush I am tapping the ever so thin layer of slag off the weld bead. Then by
simply turning the welding brush over and rubbing it a few times reveals a very easy cleaning weld bead.
A gas assisted solid mig welding wire is the most commonly used wire in general welding and fabrication shops. This
wire needs to use some kind of shielding gas for it to work.
One of the most popular choices of welding gas to use with solid mig wire is a mixture of carbon dioxide and argon
in the ratio of Co2 25% / Ar75%. And the most commonly used solid mig welding wire is what is called an ER70S-6
class wire.
The photo below is of a weld that I made using solid mig wire and mixed gas.
This is a good example of a weld you can expect when using a precision quality solid mig
welding wire.
Granted the weld bead is not dead straight as it was not welded in a robot, and my hand was
moving a bit. But the reality is, a weld like this will be good enough for any kind of job at home and good enough
for any general welding and fabrication work.
Solid mig wire. ER70S-6 + mixed gas
"See how there is no spatter anywhere."
The only thing done to this weld was to go over it with a wire cupped brush on an angle
grinder a few times.
This wire will run a straight Co2 gas as well as mixture of argon and Co2 gas as well. Carbon dioxide gas is much
cheaper to manufacture than the mixed gases so therefore it is cheaper to buy. It offers deeper penetration and
allows for higher torch duty cycles.
This picture shows a smaller aerosol can type disposable gas bottle
for use on the smaller 110volt and 240volt mig welders.
On the downside to using carbon dioxide gas when mig welding is that there is more spatter generated from the
welding arc. In Australia the gas of choice is the mixed gas of Co2 + AR 25%/75%. But in Asian countries straight
Co2 is more popular.
So to recap use an ER70S-6 mig wire with a mixed gas of Co2 and Ar 25/75 and you will get very acceptable welding
results in terms of fusion and penetration with smooth weld bead surfaces and less spatter than when using
Co2.
By reducing the amount of spatter from your welds, you can greatly save on labor costs by not
having to spend so much time on the angle grinder. This will also save money by not using as many abrasive wheels
like grinding discs, sanding discs and flap discs.
Conclusion
So to answer the question . Which mig wire should I use gasless mig wire or gas wire? The choice is really personal
and up to you.
If you can live with the extra spatter and a bit of slag and smoke. And you only need to mig
weld every now and then, gasless mig welding wire would be a very wise choice.
If on the other hand you will need to weld daily, you will probably be better of using a
solid mig wire with a shielding gas.
Gasless mig wire has received a lot of bad "vibes". People say that it is no good and a waste of time.
Gasless mig wire does perform very well indeed, with weld bead apperance much like that of gas assisted solid
wires.
If you are welding at home and all you want to do is basic repairs and general fabrication, the question arises of
which welding wire to use.
