1slow01Z71

iTrader: (36)

100% argon or 75% argon 25% CO2 I have heard mixed opinions. Im picking up my MIllermatic 140 MIG this friday.

Jokeman

iTrader: (4)

90% helium, 7.5% argon, and 2.5% carbon dioxide

1slow01Z71

iTrader: (36)

Thats the first I have heard/read about using helium.

Phoenix 5.7

iTrader: (7)

thats if ur using stainless wire right?

Silverback

the Tri-mix stuff (with He) does give you slightly better weld "flow out" (the He makes for more heat in the weld) and reacts slightly less with the base metal, but isn't absolutly necessary unless you're making food grade welds. For most use C25, like you'd use for most mild steel welding will work fine.

100% argon doesn't work well for mig welding anything besides aluminum

1slow01Z71

iTrader: (36)

IS C25 argon 75 and CO2 25? Im a welding noob obviously.

Silverback

yep...

ghettocruiser

iTrader: (17)

I use 75/25 mix with good results. Thats with using either 308 or 309L wire. Its not the greatest, but will make a decent, strong weld. I havent been able to make any REAL pretty welds with it. But I was welding exhaust mostly which was kind of a pain in itself.

J.

LS1curious

No CO2 with stainless. It contaminates the weld. Flows out good but the weld is alway nasty.

TchargedLS1TA

iTrader: (9)

I use just straight argon. Helium is too hot- it penetrates better if yor good with it, but if not, you'll just melt through your workpiece

xfactor_pitbulls

iTrader: (16)

I was taught to use 95% argon, 3% CO, and 2% oxygen. The oxygen is supposed to help the weld cool more evenly. To be honest though I usually just run 100% argon, even though I dont mig stainless very much. With the tig it is 100% argon.

M3 Muscle

Also it is good to coat the inside (or underside) of the pipe with solar flux. It helps with porosity of the weld the same as back gasing.

SScam68

iTrader: (20)

Why don't you just ask the retailer, or where ever you're getting the gas, what needs to be used for the type of weld, base material and type of wire.

Too many opinions here.

BigJls1

X2

Use small dia. wire to help with whatever you do. .030 worked for me, With an argon, co2 mix (cant rember the ratio) as the vendor suggested it, It was like "blueshield" number 2 or 3 or 7, I cant rember. they may make .023 wire which would be awesome for exhaust.

ghettocruiser

iTrader: (17)

I used .023 wire when I used 308 and .030 when I used 309L. 308, from what I was told, is good for stainless to stainless welding. 309L is good for mixed welding. Like stainless to mild...i.e. my magnaflow pipes (stainless) to my flowmaster merge collector (mild).

I was also told that 100% argon would be best. But I couldnt buy a whole new bottle of that just to weld a few things together. Nothing I welded was structural, so I figured Ide live with semi ugly welds. Plus with the price of steel being so high, the initial purchase of the bottles is getting alittle crazy. Ill take my $15 refill of 75/25 and nasty welds over a new bottle that Ill only use once.

J.

BADD SS

iTrader: (4)

100% Argon

I have tried helium mixes, but heliums too expensive now for its slight advantages

Silverback

have you ever actually tried MIG welding anything with straight argon? It's just about impossible to lay down a nice bead on anything with straight argon. The only thing that it works well on is aluminum, and even that is for a fairly narrow range of applications where you aren't better off adding some He.

RiceKilla

iTrader: (15)

Used 75/25 mix on my exhaust.

BADD SS

iTrader: (4)

Have you?

Never, ever had a problem. To each his own I suppose.

01ssreda4

iTrader: (96)

at my job they require a tri mix for stainless, i weld a lot of 316L. i think is 75 argon 22.5 co2 and 2.5 he. dont quote me bc i dont pay a lot of attention to the label. i don't think that for exhaust it really matters though, i mean you aint gonna be pulling a trailer with your exhaust tip are you?