XLR8NSS

iTrader: (4)

Alright, I've decided to convert my welder over to gas but, I need to know which gas to get.

I want to weld some stainless(304) and will probably try some aluminum welding also.

Is there one gas/mix that can be used for any type of welding with stainless/aluminum/mild? I want to get a cylinder this week/weekend so help me out.


John

felton316

I know at my shop, the welders use argon with 10% helium for aluminium. I'm not sure what they use for stainless.

jimmyblue

iTrader: (11)

Mild steel usually Argon 75 (25% CO2).
But this will leave carbon **** on
stainless, in my experience, and I think
straight Argon is the way to go. I got an
"owner bottle" at Harbor Freight store
for only $75. God Bless the Chinese!
If you want strong penetration on plain
steel then use straight CO2. Argon on
mild steel is OK, but makes for even less
penetration than Ar75 (which may be a
good thing). Straight Argon is also usable
on aluminum, where Ar75 pops like a bastard.
If you only have one bottle, go with straight
Argon.

XLR8NSS

iTrader: (4)

Man, thanks alot Jimmy and felton.

I've never used or bought a gas bottle before. I just figured you paid a deposit for a bottle and just kept taking it back and exchanging it for a new one when you emptied it. I'll have to check out the welding supply places(The Three Mules ) policy/prices to see if I should just buy my own bottle. I'm going to check it out this weekend.

Less penetration with this little welder wouldn't be a good thing but, for the light stuff I mess around with I don't think it'll be a problem. It can weld 1/4 mild all the way through with two passes(front and back) with the flux core wire.

Thanks again.

jimmyblue

iTrader: (11)

Flux cored wire has no cooling flow and will
penetrate more than a gas-shielded true MIG.

You can get rental bottles and if you move
around a lot this is maybe a better way to go;
they will charge you a deposit (that may be as
much as buying outright) but you get it back.
The thing about owner bottles is, you don't get
to keep yours, you get exchanged, and different
welding supply places don't always take each
others' owner bottles as exchange (on account
of being bitches). Then you have to go and put
some Bondo in the stampings they used to ID the
tank and repaint it so they don't notice. Not
that anyone I know has ever done that.

For sheet metal work and maybe even exhaust,
less penetration is what you want (too easy to
blow through with flux cored wire).

XLR8NSS

iTrader: (4)

That's what I've read about flux core. It can be used on a lower power setting than non-flux core wire since it has no cooling from the gas.

I think I'll just do the rental bottle thing. They don't charge extra if you have it for a few years do they. I think I'll get a little/medium sized bottle to start.

Thanks for your help.

2001CamaroGuy

iTrader: (6)

I use pure Argon with my Tig welder (mild steel, aluminum, brass, stainless, etc...) and 75%/25% Argon/CO2 with the MIG (mild steel only).

Cal

iTrader: (1)

The local AirGas welding supply told me to use C25 (75%Argon/25%CO2) for mild steel and chromoly, and straight Argon for aluminum. My Miller 210 has two independant sets of regulators and plumbing for the two types of gases, so I can switch at will. I've also welded stainless exhaust systems with the C25 and ER70S-6 wire with very good results although you're supposed to use stainless steel wire. If you weld aluminum you really need a spool gun because the the aluminum welding wire is too weak to be pushed through the MIG cable. Much better than a MIG would be a TIG if you want to weld a large variety of metals, but they cost big bucks.