Millermatic 250 gas setting

[cassidy]

Hey guys I recently picked up a older but like new Millermatic 250 welder. What should the pressure on the argon regulator be set to, the previous owner has the gas maxed out, he used it to do bodywork and has .023” wire in it. What’s the best size of wire for general purpose shop work such as building car trailers, frame repair etc? I was thinking .035” possibly? Thanks for any advice


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[cvairwerks]

Not a MIG guy, but I believe you set a flow rate and not a pressure for MIG.

 

[BukitCase]

cvairwerks is correct; but most MIGs these days actually come with a PRESSURE gauge - the gauge reads the pressure drop across a fixed orifice, so an increase in FLOW causes the gauge to read higher - some people swap these out for an actual FLOW meter (a "bouncing BB" type) - but the pressure gauge type works OK as long as there are no leaks in the system...

Typical shielding gas flows run from 15 to 25 CFH; less than that will give you porosity problems and much more than 25 will tend to re-shape the puddle IIRC -

I have a MM211 digital and an MM252, normally run 20 CFH unless there's a VERY SLIGHT breeze (you can barely feel it on your face) or I'm running thin metal (23-24 CFH seems to reduce burn-through)

.035" wire is all I run, it's a little touchy on 16 ga. but I've welded 3/4 plate with it, I hate having to pull the wire out of the gun, change liners, etc, for a small job - for REALLY light stuff sometimes I'll just use .023" in my spool gun- gun's a bit clunky for tight spaces tho...

For a LOT more, check out weldingtipsandtricks.com - if Jody can't weld it, it's probably made out of pnut butter ...Steve

 

[sberry]

The 250 is a 035 machine. It will run them all and the tiny wire is better for auto body sheet but the 250 has the power to use larger wire, is way faster and cheaper to put more wire with the same gas and time. Start at 15 gas, go from there. Saves a lot of money to keep it down.

 

[dr_clyde]

If you have the standard 2 gauge welding gas regulator, one gauge will be graduated for high pressure, and the other side is used to measure flow. The high pressure side reads the supply pressure. Usually from a cylinder. The other gauge is typically graduated in both LPM (liters per minute) and CFH (cubic feet per hour). For general shop welding, I run 15-20 CFH on pretty much any welder in the shop. TIG MIG or otherwise.

I have two 250 class miller welders. I run .035" wire in both. I have a spool of .023 for thin sheetmetal work, but I haven't had it on in years.

My favorite wire is Lincoln's SuperArc, but their SureArc is a bit cheaper and runs pretty well. SureArc is designed for automated welding where feeding consistently is super important.

Not a fan of cheap wire. A good spool will set you back $75 for a 44lb spool but in the home shop they last a long, long time.

 

[Lelandwelds]

The 250 is a 035 machine. It will run them all and the tiny wire is better for auto body sheet but the 250 has the power to use larger wire, is way faster and cheaper to put more wire with the same gas and time. Start at 15 gas, go from there. Saves a lot of money to keep it down.

The small wire is slightly easier for body work. The early generation of MM250 was a low inductance machine and a little agressive on the little end. Great welders.

 

[dr_clyde]

It's worth noting that he said the PREVIOUS owner used it for body work. OP is going to use it for fab. .035 wire all day.

 

[Bopbop]

I have a Miller 250 mig welder. It is about 25 years old. This is a great machine. Like it was said above use the .035 wire and set the regulator flow at 15 to 25 CFH. You may need to play with the flow some depending on the gas. Straight CO2 vs. Mixed gas. I second the comment about using the best wire. Pay the price for the good stuff.

 

[sberry]

The LWS is about like a card in a whirlwind. i have used L56 especially back in the day. Used it in large and 10#. I had some other wire on 10 that didn't work great but it was 20 years ago. Hobart is good. A while back i priced some and the house brand, a generic China wire they carried was about 1/2 price. He said it was good. It was, really good in my pos 255 Wirematic which is fussy. Next time I say,, great, give me the same thing. Don't have it anymore but got WA or Radnor, I figure ok, about 20$ more. Not the same, put it in directly following, night and day difference. I should have bought another roll of China right after I see how good it ran. I don't care for the Radnor 7018 but I am not as fussy or well practiced as I was 15 years ago.

 

[koditten]

My MM 250 is set at around 5-8 on the secondary gauge. I don't think I've changed the settings in 20 years.

I tossed the flow gauge years ago. It was fun to watch when I got it, but was really useless after getting the flow set.

 

[koditten]

I like what you say about wire, Cary. If you buy a brand that is treating you great, better go back and get a spare roll. Even though they are labeled the same, a couple years difference can be by a world of difference when it comes to welding.

 

[sberry]

That stuff ran as good as any I ever used. Was in a white box, no label.

 

[Lelandwelds]

I second the comment about using the best wire. Pay the price for the good stuff.

Only way to tell if it is good is to run it. Airgas changes the source for Radnor often. (They may charge more than the OEM does under the name brand.) Lincoln lists twenty or so countries as the origin for the wire they draw down for L-56. Two of my favorite wires used to be Imperial (who mostly made floral wire and construction industry stuff) and an Italian whose tiny plant only had 200 amp electrical service and struggled to send our container on time. Kobelco and Esab is nice. Hobart is good. I am pickier about dualshield.

Sorry, I got the OP bodywork vs structural wrong. I am sure he gets that gas flow isn't brand or work dependent. Many flow gauges aren't accurate anyway. "If your weld is ugly colored, bump it up" is probably the best advice.

 

[Lwel9226]

Miller 250... about 12 CFH with .030 wire..... think I'll go to .035 wire the next time I run out...... tried .023 for a while, didn't like it very much, couldn't turn down the heat enough!!!

LynnW