80/20% gas mix?

[dobbslc]

An actual welding question for once
Is this mix of gas a common option?
80% argon 20% Co2.
I'm asking as I got a midi sized (2.2liter?) disposable bottle of gas with my GYS machine that I think was an 80/20% mix, that welded so well but unfortunately it didn't last that long so I ended up using the smaller more expensive bottles from Halfords that are definitely not as good for me.
I think these were just pure Co2, so what's the difference between an argon rich mix compared to Co2?
This is mainly for thin metal welding with a bit of 4mm angle iron now and again.

 

[Onthespotwelding]

5% co2 in argon is good for thin sheet metal up to about 6mm

20% co2 in argon is an industrial mix it’s really only suitable for thicker metal.

I have a cylinder of each and it does make a difference to flow, penetration and spatter.

 

[zzr1200]

I use:
5% up to 6mm (and have tried it for mig spray mig weld), 20% for above 6mm dip/spray transfer.

Stop wasting beer tokens on disposable bottles, Adams, Hobby Weld or SGS, is the way to go 20 ltr bottle, painful the first time then it's just a refill cost....

 

[dobbslc]

Interesting.
Would a 20% mix weld 'smoother' than a 5% one on thin metal?

 

[dobbslc]

Stop wasting beer tokens on disposable bottles,

I've got to return a bottle of pure argon I don't need anymore and get myself a bottle of mix gas this weekend so was wondering what to get, I don't want a 10 liter bottle of the 'wrong' gas as I don't use much.

 

[zzr1200]

I've got to return a bottle of pure argon I don't need anymore and get myself a bottle of mix gas this weekend so was wondering what to get, I don't want a 10 liter bottle of the 'wrong' gas as I don't use much.

The 20 ltr bottle is the half size bottle, easy to transport the most gas for your money, unless you go to a full size cylinder which can be a pain to transport. I used 20 ltr bottles for years, now I have both 20ltr and full size, the best of both worlds, capacity and transportability for mobile jobs...

 

[RWD3M]

Wasn't that what BOC used to call 'Argosheild Heavy' Sort of rings a bell.

 

[Dcal]

For thin stuff 5% is better.

The more CO2 the deeper the penetration which isn't what you want on thin steel.

 

[Munkul]

Interesting.
Would a 20% mix weld 'smoother' than a 5% one on thin metal?

no, but 80/20 will weld smoother than pure CO2.

the higher the CO2 %, the higher the voltage needed for a given arc length. This means when you want lots of penetration, you run higher CO2 and voltage, giving more arc energy.
But pure CO2 isn't great for heavy welding due to something in the as-welded metallurgy.
So 25% is usually the max for heavy MAG welding.
The less CO2, the wider the sweet spot is for short-circuit welding on thin materials. So it's generally smoother and easier to get right - within reason. The machine makes more difference at low amps than the gas, in my experience.

You can usually make anything work, but some combinations are preferable for certain jobs.
If you're happy with 20% CO2, then just keep running it

 

[steve t]

You can get a universal aswell think it was about 15 percent

 

[dobbslc]

@Munkul
Thanks!
The only fly in the ointment here is that I'm not 100% sure what that first bottle of gas really was, GYS seems to sell the 80/20 mix. I think I might have had pure Co2 in the small disposable bottles that didn't work as well so what you said makes sense

 

[Jelly_Sheffield]

Wasn't that what BOC used to call 'Argosheild Heavy' Sort of rings a bell.

Argoshield gasses are all Tri-Mix.

Light: 93% Ar, 5% CO₂, 2% O₂
Universal: 86% Ar, 12% CO₂, 2% O₂
Heavy: 78% Ar, 20% CO₂, 2% O₂

The Oxygen content improves the fluidity of the puddle and reduces spatter compared to straight Ar:CO₂

It's not a big enough difference that I would buy it if I wasn't already tied to BOC for my Acetylene cylinders, but if you're doing long welds that needs to be very neat, it is a little bit nicer than a two-gas mix.

You can get a universal aswell think it was about 15 percent

The universal is OK for universal use...

But in my experience it's best for 4-12mm thickness, but not so bad as to be unworkable for thinner/thicker jobs.

The Light (or a 95:5 mix with no oxygen) is a lot more user friendly on thin metal.

Stop wasting beer tokens on disposable bottles, Adams, Hobby Weld or SGS, is the way to go 20 ltr bottle, painful the first time then it's just a refill cost...

Amen to that.

I go through about 1½-2 "Size W" (47L) cylinders a year, even with BOC rental charges, it's still easily half the cost of disposable bottles.