Guys, I am no expert welder but as far as I know MIG welding mild steel requires either pure CO2 or ARgon/CO2 mix.

However yesterday I saw guys at a workshop making beautiful welds with a MIG using pure Argon on mild steel.

I'm used to using CO2 and actually prefer it coz of the better penetration - have'nt encountered that much spatter yet.

But I am now seriously considering switching over to pur Argon as I can use that for my TIG as well.

Do you think it is a good idea using pure ARgon with the MIG? The only objection that I can think of is that weld area may have a lesser carbon content than the rest, but is that such a big problem?

i tried the same thing, had no succses, but that could have been down to me.......

As a spotty teenager, I was told the reason why not, buggered if I can remember though!

If you are welding SS or ALI, then go with straight argon, However when using it to do carbon steel, you will not get as good penetration even though the weld might look better. I was running straigh argon and have switched back to the 75/25 just for that reason.

David

nice avatar

We tried but couldn't get the penetration with it and the weld seemed brittle on thicker than 16g like it was cooling too quickly. Like Jon said, could have been us, probably needed to relearn the setup.

Well, I'm quite sure you guys have got more welding experience than me, so I'll stick to using CO2 for the MIG then.

Pity coz, I'll have to pay extra rental on the Argon.

i get best MIG results with "Argoshield" an argon Co2 mix.........

Yes, Afrox (part of the BOC group) also recommends that I use Argoshield, but one of the biggest reasons that I'm using CO2 is that the bottle is very portable. Important factor to consider when you're working alone on your projects.

They could'nt supply me Argoshield in a small bottle so I've opted for CO2.

I've learned tho that CO2 is a bit hot, especially on thin sheet metal, but I'm happy with the overall results.

again a problem i had too, i just used a longer pipe to feed the welder and left the bottle in the corner of the garage collecting cobwebs........

Thought of that but my garage is too cramped - too many tools not even enough room for the car.

How safe is it to store Argoshield/Argon outside? That is what I plan to do eventually and get a 5 - 10m pipe so that I can work anywhere.

Talking about Argon, wher can I get a bottle cheap and not one of the disposable ones? I always used co2 from my pub but aobviously haven't got Argon. Last tiem I went to a specialist I had to hire the bottle which increased the price. I want something I can keep for months.

I have no experience with it in terms of welding, but in a hypothetical physics thought, if you have a very long gas pipe you might get problems to do with pressure drop and or slow starting due to the inertia of the gas in the pipe.

I have no idea if the effects would be at all noticable over a 10m length of tube though. just a random thought.

most big fab shops have the welding gas traveling 10's of yards/meters from a large tank outside, you set the flow to suit the weld at the torch anyhow........

The reason you won't get a presssure drop when using a long pipe from bottle to plant is because the gas is swithed on (for want of a better phrase) inside the mig plant when you pull the trigger.
some of the bigger production companys use gas cartridges these are basicaly 10 or so bottles of gas joined together in a cage one pipe from this supplys the whole welding shop...

[Edited on 10/7/2004 by Viper]

Speaking of those little bottles you get at the hardwear store, how the hell do I fit it to my mig welder?

My welder is a 165 model CIG welder. It comes with the brass regulator that you can fit into the larger bottles you get at BOC, and it doesn't look like I can fit it anywhere. Do I need a special fitting to use the disposeable bottles?

All I got was dumb looks at the hardwear store

you'll need an adapter for the bottle as the original thread is way to big plus you usually get two square plates with holes in them where the bottles goes in and they slot into the back of the mig, if that makes sense.