GMAW Ar/15%CO2 - good? (used in UK)

I'm just a "hobby welder" and my machine is a light duty Lincoln Weldpak 100 , but I've been using straight CO2 for years . I don't have what I consider excessive spatter ... Most MIG users here - including my neighbor who is a pro weldor - are using 25% CO2 unless they're welding aluminum , which calls for pure argon . Seems like from what you've posted here in the past that the industry there isn't willing to try anything new ... any chance you could rig a setup that would allow you the mix your gasses at different proportions to test your hypotheses ?

I use BOC Argoshield light which is 93% Ar, 5% CO2, 2% O2 I've never had a problem getting it. The Argoshield Universal is 86% Ar, 12% CO2, and

Snag - is commercial welding - fine line with productivity and cost. With a big industrial welding machine on 3-phase power, you can and will be using spray transfer a lot of the time. Around 8kW at the arc. More into the machine. This gas optimisation is about getting good spray transfer, which starts at 240A 29V - lowest commercial spray transfer condition and a nice condition actually.

OK - thanks for relating experience. It's the "Argoshield Light / Medium / Heavy", a catchy marketing slogan from some time ago, which is exactly why we have this problem, with it becoming an orthodoxy. There was only dip transfer then, which contributed to getting it fairly much the wrong way around. The problem is most have qualified their welds - done WPQR tests, with all the costs of witnessing and tests - with Ar 20%CO2 (2%O2) - which is in gas category "M21". Ar 12%CO2 (2%O2) is in gas category "M20". Which I suspect these days you'd want. But there's no way for me to know. Requalifying welds - expensive. "Painted into corner". A situation that's more political than technical?

I don't know if with 5%CO2 you'd have enough "bite" to do dip transfer on positional thick plate and box-sections (SHS, RHS - efficient low thicknesses compared to plate and beam)? Honestly - never chance to try, and no-one to ask.

I don't know how long the Argoshield gases have been around it's just what I use currently. My venerable old Eland MIG is only 160A so dip transfer only AFAIK but it suits my needs fine. The only time I've had the pleasure of trying spray transfer was at a small welding show back in about 1985 in Bristol and it worked great but I don't need to weld

Commercially - if "spray" would be advantageous, do it, obviously.

• penetration / fusion - very adequare - not absurd - about "Goldilocks quantity" = just right

• * no spatter * - not spending ages tidying-up / de-spattering

• washes away oxides - totally satisfactory welds low Execution Class 2 over light off-the-mill black scale and weldable primer.

• smooth low-effort welding - very radiatant arc illuminates area for easy view of weld

• etc.

By the way - best have a long shroud on torch which is optimum for spray.

Spray puts a lot of heat load on the torch. So one of

• water-cooled torch

• big spray-capable air cooled torch

• only spray where necessary, dip transfer when can get away with it - and "enhanced air cooling" - puncture a fine hole through a plastic bottle top, fill with clean water, and between runs squeeze bottle to make "spider's web strand" jet of water onto air-cooling fins of torch until stops evaporating

Reminds me I have come a long way, even if I am aware there is still so much to learn - only know a fraction of what someone does if have been a welder non-stop since leaving school.

David - sounds like a very good technically sound choice. "stick"/SMAW has that advantage. 'tother advantage is - while "stick"'s doing nothing, it's costing nothing. Good for infrequently used process, obviouisly. Whereas MIG/GMAW - gas bottle hire - need regular work to justify it. Well, you know all this. Just agreeing, for what it's worth. Rich S

Every bottle I have here is owned , not leased ... I leased an oxygen bottle for a couple of years because the supplier (NLR out of north Little Rock Ar) refused to refill my 20 cf bottles . When I found a supplier that would and returned that leased bottle , the new manager GAVE me a couple of empty 20's as an apology for the previous manager's being an asshole . They could have filled MY bottles rather than swap them , but he was an asshole who didn't like "small guys" .

Every bottle I have here is owned , not leased ... I leased an oxygen bottle for a couple of years because the supplier (NLR out of north Little Rock Ar) refused to refill my 20 cf bottles . When I found a supplier that would and returned that leased bottle , the new manager GAVE me a couple of empty 20's as an apology for the previous manager's being an asshole . They could have filled MY bottles rather than swap them , but he was an asshole who didn't like "small guys" .

Same here in NH, but the dealers will sell only the smaller portable tanks, not the industrial sizes.

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The only big tank I have is the argon for the TIG welder , it's a 300 cf . CO2 , oxy and acetylene are all the smaller bottles . That's OK though , I don't use that much of any of them - my last argon bottle lasted like 3 years . I might use a pair of OA bottles (20 cf O2 , "B" tank of acetylene) in a year ... especially now that I have a plasma cutter .

I am a big fan of owner bottles. I have several, and will probably get a couple more.

I think Snag was talking about setting up a gas mixing setup to test your ideas. I have not seen one, but I seem to recall people talking about having such a rig right here on this group in years past. They hook up two bottles and the rig mixes it to give you the desired ratio.

Oh if I've misread his post and said something skewy I extend apologies to Snag.

Bob is right about what I meant , and no apology needed . What you need is 2 (or more) flow meters working at the same pressure , you adjust the flow meters to the desired proportion - say 20 cfh Ar and 10 cfh CO2 would give you 66/33 . You can regulate the actual gas flow downstream , the critical factor is the ratio from each source .