MIG with no gas?

All of those tiny MIG welders are set up to use flux-core wire. These don't require shielding gas. Some of the welders can be set up with gas also, sometimes using hardware that costs extra. The hitch in the getalong is that it is very difficult to get a clean looking weld with fluxcore technology. That's probably why if you look at your local craigslist you will see dozens of MIG welders for about $200 - would all those guys be selling them if they worked for them? Not a chance.

Technically MIG isn't a correct term anyway, "wirefeed" is roughly synonymous with how it's currently used. Formal welding terminology is SMAW (shielded metal arc welding) or FCAW (flux core arc welding).

GWE

Maybe you can answer a question...

Is MIG a continuous arc, like TIG or DC stick or is it a series of sparks?

"Jim Stewart" wrote: (clip) Is MIG a continuous arc, like TIG or DC stick or is it a series of sparks? ^^^^^^^^^^^^^^^^ My MIG, a Lincoln 135, is DC, and it's continuous arc. Answering an earlier comment, flux core does not produce quite a clean a weld as gas shielded, since there is a thin deposit of flux over the weld. That's not hard to brush off, however. On the other side of the ledger, I'll tell you why I use it. My welder is small enough to be portable, and I don't want to drag a tank of gas along with it. Flux core works quite well out of doors in any breeze. Gas shielding requires still air. I'm still up-in-the-air about which is cheaper to operate. Flux core wire costs quite a bit more, but then there is no tank to buy or refill.

Calling flux-core "MIG" is technically incorrect, but that's the way language is. Words get used wrongly, and then usage forces their adoption.

There are at least two modes of SMAW. In one, the wire touches the workpiece, creating a short circuit, which heats up the wire very fast and it melts back, breaking the short circuit. As the wire advances, it shorts again. This is called "short circuit" mode and is characterized by the sound, which is often described as bacon popping in a frying pan. In the other mode, the wire is literally turned into tiny atomized droplets by the combination of the heat and the strong electric field, and the metal particles are injected into the puddle. This mode is called "spray mode", runs at very high currents, requires a very heavy duty machine, and is characterized also by the sound, which is a smooth hum.

GWE

If you do any serious "MIG" course in the UK it's hammered into you that it's MAGS rather than MIG, unless you're actually using an inert shield, like argon.

Both. There are a number of transfer processes, depending on how you set the machine. "Spray transfer" is continuous. You have a decent voltage and turn the wire speed up, then the wire melts at the torch and flies across in a continuous stream.

"Dip transfer" is used on thinner work, with smaller machines, or if you're using CO2 (a good reason not to use it). The wire is fed out, contacts the workpiece, and the arc melts the tip off. This then repeats with the intermittent low frequency buzz you're familiar with. It's a workable process for thin sheet, but it doesn't have the penetration for thick stuff.

"Globular transfer" is the bad process behind the pigeon crap welds. The blob forms at the torch, then flies across in one go. As it's too cold when it hits, it doesn't fuse cleanly. This is usually caused by inadequate wre feed for the voltage.

Any shop using C25 at a moderate current is below spray parameters. That doesn't mean they're doing pigeon crap welds or getting no penetration. They would be experiencing more spatter than in spray mode. There is a workable range below spray that includes globular transfer and definitely does not result in a cold weld.

Yes, and the "I" stands for inert (gas). Inert gases are argon or helium. And you can't produce them with core wires. The "A" in MAG stands for active (gas). A gas like CO2 (or O in little doses).

Seems that many people don't know the difference between MIG and MAG.

Nick

definitely does not

Globular transfer is _never_ right. If you're not working spray, you should be working dip. Melt a blob if you want, but do it on the workpiece, not on the tip.

Wrongly? :)

Q.E.D. (quod erat demonstrandum) ;-P Get it?... Good!

-->--

"Dave Lyon" wrote: Wrongly? :) ^^^^^^^^^^^^^ Webster's Second Edition, Unabridged: "Wrongly, adv., in a wrong fashion or way."

QED - I always think of the book of the same TLA. QED "The Strange Theory of Light and Matter" by Richard P. Feynman

Quantum Electrodynamics or QED for short.

However I seem to recall - that is the solution or that is it.

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH, NRA Life NRA Second Amendment Task Force Charter Founder

Bruce L. Bergman wrote:

On Wed, 09 Nov 2005 22:18:28 -0600, with neither quill nor qualm, "Martin H. Eastburn" quickly quoth:

Sounds fun, and my local library branch has a copy. Nexxxxt! (Dick's a fun guy.)

I just finished Honda's service tome on their Big Red trikes. My neighbor Glen's trike is stuck in 3rd(?) gear and he was taken for over $600 by an off-the-street bike repairman who split with his cash and a few of the parts he removed. To top it off, he went in for heart valve replacement surgery last month and his wife (who had suffered in bed for 4 years) died on Tuesday night. I'll see if I can help him with it on Saturday, before the funeral services.

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MAG is not a common term in the U.S. The official AWS term is GMAW for Gas Metal Arc Welding which fits both MIG and MAG. We tend to use MIG as a general substitute for GMAW despite technical inconsistancy.

Cheers,

Kelley.

MIG machines can also use a type of filler wire called flux core which needs no inert gas to keep the puddle from oxidizing. this wire is great for welding on dirty/greasy carbon steel and gets good penetration although it does spatter quite a bit. it runs very smooth in all positions. it is very forgiving in tough situations.