Buying my first MIG welder

[Ian B]

All my life, when I've wanted to join bits of steel together, I've used a stick welder. 99% of what I do is stuff like 2" to 4" box section, angle, strip, that kind of thing. Very rarely stainless, and nothing that's going to be used on the space shuttle etc. I have a 350A Lincoln AC stick welder.

I'm now tempted to go for a used MIG welder. Largely because of the reduced mess from slag.

I had a go with one, and was surprised how easy it was to use. The one I tried was this one: http://www.parweld.co.uk/wp-content/...age.pdf?x71399 300A at 30% duty cycle. First welds that I made looked lovely, much to my surprise.

Really nice machine, but 1400 euros new. I'm looking to pay about half of that, for a used machine. There's lots on the market in that price range, also from known makes - Esab etc.

What should I look for when buying? The owner mentioned the 4 roll drive as being desirable, along with having most things adjustable (soft start etc). What goes wrong with these things?

The machine was set up with 0.8mm wire; will this do for most jobs?

Considering that I'll only be welding mild steel (no stainless / aluminium) with it, what are the "must have's", what can I do without? 3m of hose will be enough; it'll live beside a dedicated welding bench. Maximum metal thickness that I'll need it for will be 10mm, maybe occasionally more, but I'll keep the 350A stick welder for that. I'm looking for a 3 phase machine, as I have a 380V 25A power supply.

I don't think that I'll need a water cooled torch; I don't do huge amounts of welding, and I can afford to let things cool down. Not sure what I'll do about the gas bottle; buy, rent? A cylinder will probably last me 2 years, and I have a supplier around the corner. Equally, getting the welding wire is not an issue. The one I tried was a CO2 / argon mix.

Wise words?

Thanks,

Ian

[RMinMN]

Is all your welding with mig going to be done indoors? Air movement outside can blow away the shielding gas in which case you no longer have it protectiing the weld.

Amperage of the welder determines how thick metal it can join in one pass. Making your weld joint with a good vee can allow a lesser amperage welder to penetrate that bottom of the vee and subsequent passes don't have to penetrate to the bottom of the weldement.

Wire feed welders that use flux core wires can be pretty easy to use but the weld won't be as pretty. They can be used indoors or out since they don't use shielding gas making them cheaper and more flexible.

Look at some Youtube videos on mig welders and see what amount of money gets you what results. Note that wire feed welders like clean metal. I work on my old farm machinery and it may be dirty and will for sure be rusty. Sometimes the location of the break doesn't allow for grinding for cleanup. My stick welder doesn't much care, my wire feed balks.

Welding professionally needs a welder with a high duty cycle as time is money and waiting for the welder to cool costs money. Welding at the hobby level may not need the high duty cycle. Some of the newer cheap wire feed welders have a pretty high duty cycle too. Do your research.

[Ian B]

Yes, all the welding will be done indoors, so wind's not an issue. I wasn't planning on using flux cored wire, just the usual copper plated solid strand; probably 0.8mm, as this seems to be common.

The machine I tried had a 30% duty cycle. The owner is a professional user, and - so far - he hasn't had problems with overheating. My level of usage will be far lower than his, so from that, I'm thinking that 30% would be more than adequate for my needs.

Interesting point about the cleanliness of the work. Most of what I do is on clean box, angle etc, but that's another good reason to keep the old stick welder.

Thanks,

Ian

[RMinMN]

I think that 30% duty cycle will let you weld constantly at the highest setting for 3 minutes straight but then the welder needs 7 minutes of cooling. I have trouble welding for more than a minute before I need to change positions and the welder cools while I am doing that. I've never been able to heat my cheap wire feed to the point that it shuts me down.

[JoeLee]

All my life, when I've wanted to join bits of steel together, I've used a stick welder. 99% of what I do is stuff like 2" to 4" box section, angle, strip, that kind of thing. Very rarely stainless, and nothing that's going to be used on the space shuttle etc. I have a 350A Lincoln AC stick welder.

I'm now tempted to go for a used MIG welder. Largely because of the reduced mess from slag.

I had a go with one, and was surprised how easy it was to use. The one I tried was this one: http://www.parweld.co.uk/wp-content/...age.pdf?x71399 300A at 30% duty cycle. First welds that I made looked lovely, much to my surprise.

Really nice machine, but 1400 euros new. I'm looking to pay about half of that, for a used machine. There's lots on the market in that price range, also from known makes - Esab etc.

What should I look for when buying? The owner mentioned the 4 roll drive as being desirable, along with having most things adjustable (soft start etc). What goes wrong with these things?

The machine was set up with 0.8mm wire; will this do for most jobs?

Considering that I'll only be welding mild steel (no stainless / aluminium) with it, what are the "must have's", what can I do without? 3m of hose will be enough; it'll live beside a dedicated welding bench. Maximum metal thickness that I'll need it for will be 10mm, maybe occasionally more, but I'll keep the 350A stick welder for that. I'm looking for a 3 phase machine, as I have a 380V 25A power supply.

I don't think that I'll need a water cooled torch; I don't do huge amounts of welding, and I can afford to let things cool down. Not sure what I'll do about the gas bottle; buy, rent? A cylinder will probably last me 2 years, and I have a supplier around the corner. Equally, getting the welding wire is not an issue. The one I tried was a CO2 / argon mix.

Wise words?

Thanks,

Ian

A water cooled MIG ???? I've never seen one and the spec sheet for the OP's welder doesn't mention anything about it. Are we thinking TIG ??

JL..................

[Ian B]

Joe,

The water cooling that I referred to was for the torch itself, not the box of electrics. Some of the torches have a water circulation unit. Here's one: http://www.parkinsgroup.co.uk/prod/1...oled-mig-torch

The one I tried didn't have water cooling, although the owner has another MIG that does have it. Again, I don't see me needing it - just more weight & complexity.

Ian

[MattiJ]

A water cooled MIG ???? I've never seen one and the spec sheet for the OP's welder doesn't mention anything about it. Are we thinking TIG ??

JL..................

Water cooled MIG torch/handle/cable is common on high amperage MIG's but for home shop usually a total overkill.
Water cooled mig torches are typically used above 300 amps or so. Continuous duty 600 Amp rated air cooled torch/cable would be rather heavy.

[JoeLee]

Joe,

The water cooling that I referred to was for the torch itself, not the box of electrics. Some of the torches have a water circulation unit. Here's one: http://www.parkinsgroup.co.uk/prod/1...oled-mig-torch

The one I tried didn't have water cooling, although the owner has another MIG that does have it. Again, I don't see me needing it - just more weight & complexity.

Ian

I understand that......... I have a water cooled torch for my Miller Syncrowave 250, only used it a couple times when welding 1/2" thick alum. plate.

I never knew water cooled existed for MIG guns. I've seen some pretty big MIG welders in other shops but never seen one with a water cooled gun.

JL............

[oldwing]

A water cooled MIG ???? I've never seen one and the spec sheet for the OP's welder doesn't mention anything about it. Are we thinking TIG ??

JL..................

Would this work?https://m.youtube.com/watch?v=x2ai5eDzvxU

[Black Forest]

I personally don't like the step adjustment on a MIG welder. I like to dial in the voltage a little closer. Buy your bottle. Argon/co2 mix is what you want for welding steel most times.

[CPeter]

After 55+ years of stick welding, I finally bought a mig welder about 3 or 4 years ago. It is a Lincoln Power Mig Dual 180. It can use gas or flux cored wire and will plug into either 120 or 240V. I use argon/co2 and solid .030" wire 95% of the time. I have welded up to ½" with multiple passes. I normally am welding 1/8" and ¼" stock and it is really nice not to have the slag to deal with. I do use a spray bottle of anti spltter stuff that keeps any splatter from sticking. Unless you are in a production facility doing really thick steel, I can't see that anything bigger would be necessary. All my other welders have been Miller and I have Hypertherm plasma cutters, but I really like the Lincoln Mig that my welding store suggested. They do sell Miller and maybe ESAB, too.

http://www.lincolnelectric.com/en-us...ncolnElectric)

CPeter

[Black Forest]

I like the four roll feeders because you don't need to clamp or tighten the rolls as tight as on a two roll system. Which means you don't deform the wire and you will have less chance of bird's nesting the wire inside your welder if you put too much of a bend in the hose to the gun. A bird's nest is when the wire doesn't feed out the end of the gun but the wire is still being pushed inside the machine so it creates a "birds nest" of wire.

[JoeLee]

How does a four roll feed system work as far as preventing "bird nesting" ?? My MIG has one roll of wire. Never had a feed problem with steel wire.

Bird nesting usually happens when the feed line gets clogged with shavings or other contaminates, or kinked.

If the line is plugged all the rolls in the world won't push the wire through. It has to be cleaned.

JL.............

[Ian B]

Thanks guys, that's what I'm looking for!

BF, on the Argon / CO2 mix - is there a common percentage mix that would do me? I can imagine every mix being available. I'd be looking for just one, if I could get away with that.

Joe, on the 4 roll thing. It's not about the rolls of wire (there's still only 1 roll). It's the feed mechanism that pulls wire off the roll and pushes it to the handset. Smaller / cheaper machines have 2 rollers, the wire is pinched between them. I've had a system recommended that uses 2 pairs of rollers - seems this gives more drive as it spreads the load.

Ian

[3 Phase Lightbulb]

How does a four roll feed system work as far as preventing "bird nesting" ?? My MIG has one roll of wire. Never had a feed problem with steel wire.

Bird nesting usually happens when the feed line gets clogged with shavings or other contaminates, or kinked.

If the line is plugged all the rolls in the world won't push the wire through. It has to be cleaned.

JL.............

I think he's talking about feed rollers, not wire rolls. There are steel feed rollers that pinch/grab the wire and feed it through the flex tube and out the gun.