How to: MIG Weld

The workhorse process for automotive. Strong, functional, and good looking.

How to MIG Weld.
“A grinder and paint makes a welder what he ain’t” – My dad

So, you want to MIG weld? The first thing you’re going to have to do is start criticizing other people’s welds on the internet. This is the first step, and the best part is, that there’s no welding experience required! Murphy’s law states that the best way to get the right answer on the internet is not to ask a question; it’s to post the wrong answer. Since the interweb welders have been SO gracious in giving their constructive criticism over the years (sarcasm), I’d figure I’d compile all of the comments that I’ve received on my welding videos for you to peruse. Approximately 400k subscribers know that I’m no artist with a MIG gun, but hey, here are some of my tips and tricks to help you out. Let’s get started. 

Why MIG? Why not TIG or Flux-Core?
“WHY THAT WELD LOOK LIKE CANCER IN A BABOONS BUTT.” -Anonymous Commenter

First things first, let’s go over some of the basics. MIG welding stands for Metal Inert Gas. MIG uses a continuous, consumable wire electrode and a shielding gas supplied by an external shield gas bottle, usually a blend of 75% argon and 25% CO2. This wire is fed to the weld pool, from the machine, through the torch, automatically. 

For automotive work, I find that MIG will be the “workhorse” process. Great for patch panels or fab work. TIG welding requires extra finesse since you’re feeding filler wire manually (however, TIG welds do look really pretty when done correctly; better for custom intakes, roll cages, that type of thing.) TIG also is a little more costly and takes much longer. 

Flux Core doesn’t require gas, but it is dirtier and a little hotter than MIG, which isn’t good for thin material. Spatter is the enemy, and too much heat will cause thin panels to “oil can”. In automotive, looking decent is kind of important. With that in mind, I find MIG to be the sweet spot for a lot of jobs.

MIG welding won’t work on aluminum. However, you can pick up the Aluminum Spool Gun, and if your MIG machine has the capability (MIG140, MIG180, MIG250) you can do it. You’ll have to switch polarities and hook up some pure argon, but you can weld aluminum with your Eastwood MIG, which is a pretty darn neat trick. 


The Eastwood MIG Welder Spool Gun (left) and the Eastwood MP140i MP200i Spool Gun (right)

Newbies beware, flux-core is not MIG. (how-to shop for a first machine)
“Nice weld. Only thing you couldn’t keep together was a family.” Ouch, dude. Chill.  

FCAW, stands for Flux Cored Arc Welding, which we’ll just refer to as Flux-Core in this article. MIG and Flux Core work almost the exact same. MIG uses an external shielding gas that flows through the machine. Flux-Core, however, doesn’t use an external shielding gas. Instead, it uses a hollow wire inside which contains flux. As that flux burns, it creates a small shielding atmosphere for the weld pool. No gas is required, which makes it great when you’re working outside of your garage/shop. You can even use a MIG machine to do Flux Core, as they both utilize a wire feed mechanism that feeds the consumable wire electrode into the weld pool. 


The Eastwood 90 Amp Flux Core Welder is strictly for FCAW as it doesn’t have a shielding gas input.

But you CAN NOT use a Flux-Core machine to MIG weld. You need a machine that has the plumbing for gas to flow through in order to MIG. That’s where the competitors get ya. They call their strictly flux–core machines a “MIG” machine. To me, that’s disingenuous. For a great first machine, I highly recommend taking a look at the Eastwood 90 Amp MIG welder. For right around $300, you can have a MIG and Flux Core welder that can handle up to ⅛”. It comes with all the equipment you need to do MIG welding, plugs right into a standard 120v wall outlet, leaves tons of room in the budget for gear, and it also comes with an industry-leading 3-year, no-hassle, warranty. 


The Eastwood MIG90 can do FCAW and True MIG welding (and comes with everything you’ll need except safety gear!)

Safety.
“That weld looks like 20 pounds of hammered dog sh*t”

Welding arcs are obviously super hot, and unbelievably bright, they give off dangerous fumes, and they also give off IR and UV radiation, so safety is very important. The first thing you need is a helmet. Helmets are impact rated, they’ll keep the sparks off your face and protect your eyes, and of course, allow you to see. I’d obviously recommend going with an auto-darkening helmet. That’s just the standard nowadays. Even when they’re undarkened, they’ll give you 100% IR and UV protection. and they darken in, not kidding here, a 1/10 of a MILLIsecond. So we’re literally talking about microseconds after starting an arc, fascinating stuff. (Remember to be sure not to block the sensors on the front of the helmet. Most helmets have multiple sensors to prevent this but it’s still possible when your head is in a tight spot) Any welding helmet you get is going to be able to do at least a shade 10. As you turn up the amps, turn the shade up to compensate. All the Eastwood helmets go up to at least 12 and most of them will go to a shade 13. Similarly, as you turn down the amps, you can turn the shade down to compensate. Just don’t go too low.

You’ll also need a good jacket or apron, some gloves, jeans, and close-toe leather shoes… Again, there are going to be VERY hot sparks coming off a weld, so, cover your skin with a non-flammable material, like a non-flammable cotton, Kevlar, or leather. Also,  you’ll need gloves too, kidskin is nice. Just keep in mind, that TIG gloves tend to be a little thinner for added dexterity but for MIG, you don’t need that so use the thicker MIG gloves for the extra protection. Also, gloves and a jacket will keep you from getting a suntan from radiation exposure which is always good to avoid. I also recommend a respirator. Breathing in these gasses for a long time is dangerous. The first time you weld, everything will smell like sweaty nickels for a few hours afterward. So, I recommend just wearing one; you don’t need anything crazier than a 2097 pancake-style filter. Lastly, a fire extinguisher is a no-brainer but is always a good thing to have close by. Be sure to unroll any cuffs as well, and make sure you have a nice tight fit. You don’t want loose clothes when welding.


JD and the recommended safety gear.

Other equipment and the right tools for the job.
“I hope Santa is getting you a grinder for Christmas” 

From there, a good workspace is a must. In the studio, I use a WeldTable. Yes, they’re expensive (even their mini tables are close to $500) but they’re a great product if you’re a “buy it for life” type of person.  It’s nice and level, it’s on casters, there’s tons of room to stick your elbows out, and a bunch of holes in it will allow you to bolt down some clamps. If you’re in a tight garage, or you’re just looking for a solid workspace that folds away, I’d recommend using the Eastwood 750 LB work stand with a welding top.

I also highly recommend some “arrow” shaped welding magnets, these can do an inside and an outside 90, and 45’s too. They’re a must-have if you ask me. The same goes for Stitch Weld Magnets. They’re super strong and you can pop them down to really hold two pieces of metal together as tight as possible. Of course, you want some heavy-duty clamps to hold everything nice, and still, once you get everything set up and laid out, you don’t want your project to shift around in the middle of a weld. Magnets and clamps are critical in minimizing air gaps between two pieces of metal. The key to a good weld lies in a good “fit-up.” Welding is just like painting, taking an exam, zombie apocalypses, or colonoscopies, the key to a good one is all in the preparation. 


Common “arrow” welding magnet angles.

Machine Setup
“looks like all the good welders at eastwood Argon” I hate this one…

Next, you want to do a basic setup for your machine. First thing is to plug it in. Most of today’s welders you encounter will run off of either a 120v (smaller machines) or a 240v (larger machines) outlet, or some can even do both. All of our MIG machines that utilize a 240v can also be adapted to run at reduced power off of a 120v outlet. This is a great feature for the beginner, if you don’t have a 220 in the garage, you don’t need it to get started with MIG welding.


240V to 120V adapter cord. Included with capable Eastwood welders. 

We also need to set up our wire spool. I recommend picking up a spool of .230 and a spool of .030. These gauges will have you covered for most automotive work. Get your wire installed by locking on your spool with the wingnut, hold the wire to prevent it from unraveling off the spool (this happens to all of us at least once), snip off the end, feed it through the drive roller and lock down the tension knob. Lay the torch cable out flat and feed the wire through. The Eastwood machines have a quick feed function. Just hold the trigger and after a few seconds, the machine will recognize that you aren’t trying to weld. It’ll set the driver rollers to max RPM to speed this up. 

It’s at this point you want to set up your gas. You can skip this if you’re doing Flux-Core. But for MIG welding on steel, most people go with a 75% Argon, 25% CO2 mixture. This mix will give good arc stability and reduce spatter. Make sure your gas hose has a snug connection between the welder and bottle. (careful not to overtighten, brass fittings are soft.) Crank the gas open and dial in your regulator. Anywhere from 15-20 cf/h will do fine. If there’s not enough gas flow, you’ll expose the puddle to the air and that will create pores, or little holes in the bead, which is known as porosity. On the flip side, you don’t want to waste any gas either. 

Next up, dial in the settings of your machine, the two big ones are wife feed (how fast the wire is coming out of the gun) and voltage (how much energy you’re imparting to the material.) This will take time and practice to develop a feel for, but understanding where you need small adjustments is what makes for a decent MIG weld. For now, refer to the settings chart inside the case of the machine. This will give you a good baseline to start with. Adjust your wire gauge, wire speed, and voltage accordingly.


The EW MIG 90 settings chart.

Really quick, let’s talk about “stickout.” This is how far the wire sticks out of the contact tip. Usually, you want to hang out in the ¼” – ½” range. Here’s what I do, I use the Eastwood MIG pliers. I press them up against the nozzle and trim the wire. The cutters are offset in the tool and this will give you a consistent stickout every time. Simple but effective. 


The offset cutters in the Eastwood MIG pliers make cutting stick out simple (cutters at the red line)

How to prep material for a weld (the more prep the better)
“You’re shaking worse than a chihuahua sh*tting a peach pit!” 

The first thing to do is to clean our material. MIG is a more resilient process. TIG requires perfect cleaning and Stick can be performed on pretty much anything, anywhere. Regardless, getting the material as clean as you can is massively important to the quality of the weld.  Rust and mill scale will ruin the quality of your arc. All you have to do is hit your piece with the flap disk, or if you have our Contour SCT, that works great. For the tighter spots, a Scotchbrite pad or a little die grinder is perfect. Following up with some Pre-Painting Prep is optional. If you use PRE, make SURE you let that dry all the way before welding.

If you have a bare metal table, you can ground to that instead of directly to the part. It’s also a good idea to make sure whatever you’re grounding to is also clean. Before getting started, it’s a good habit to clean your torch. You can use a clean wire brush to clean off the nozzle, and contact tip. Or you could use the Eastwood MIG pliers to knock the slag out of the nozzle. You don’t want that to impede your shielding gas flow. 

Technique
“Bigger the glob better the job ;)” Gross. 

Time to go. There are a TON of different ways that people move their torch. Most people start with “c”s or “e”s. “c”s are little crescent moon “c” shapes, moving slowly along the weld joint from top to bottom, with a little arc in it. I started off doing little lowercase cursive “e’s”. That’s where you make back-to-back loop shapes that double back over the weld joint in the shape of a lowercase letter “e”. There are a ton of more advanced patterns out there, in my experience, these are the most common.


“C” (top) and  “e” (bottom). Please excuse my crap handwriting. You get the gist.

No matter what you pick, controlling your eyes is one of the most important steps for puddle control. Don’t watch the wire, don’t watch the nozzle, don’t look at the material. Simply watch the molten weld puddle, focus on that and you will improve rapidly. You want to keep the proper distance from your material too. Too far away, you’ll make it tough for the shielding gas to cover the weld, which will lead to some porosity, and a poor joint overall. Too close up, you won’t be able to see what you’re doing and you’ll end up laying your head on the table in order to see, which isn’t good. Makes it even harder to get straight beads. Maintain that ¼” – ½” stickout range. 

Keep your ears open as well. When you listen to MIG welding, it should sound nice and crispy. People liken this to bacon frying in a pan. (but more consistent.) Also, I like to set up to use my other hand for some extra stability or support. You can’t always do this, like if you’re welding an inside joint or overhead. When you can, it keeps you nice and stable.  

Now, you can also push or pull the puddle along. I tend to like to push, however, you’re going to have to do both depending on the situation you’re in or what’s in your way. Regardless, don’t lean the gun over too much. A little lean is good so that you can see what you’re doing. I’d recommend 10-15 degrees either way but not any further than that. Again, you will be in situations where you’re fighting against gravity sometimes, and that’s going to change your technique drastically.

Start off with some basic welds, horizontal tee joints, lap joints, or butt joints. MIG welding is based a lot on feel. You really are juggling a lot of factors when welding, but MIG tends to be the most common functional, and structurally strong welding process. Before you weld something important, I recommend doing a dry run, make sure you have your range of motion set and you’re comfortable, then do a run on some scrap that’s a similar thickness, just to make sure you have your settings right; then go in for the real thing. 

Feeling the right settings
“colder than a witch’s tit in a brass bra” I’m stealing this one.

Voltage too high will make a wide bead, this creates a danger of melting through. Too low, will give you a cold weld. The wire will sort of bubble up on top of the piece and run into itself. Which is not good. A good weld penetrates by melting the surrounding material with the filler material. A cold weld will be a weak joint. 

When the wire speed is too fast, there’s not enough energy to melt all that material coming out of the gun, it will look cold as well. Too low will make a distinct tapping sound, this is the arc breaking and restarting itself.

Keep in mind that this is a learning process and as you go, you’ll become a stronger welder. Nobody is fantastic at this out of the gate, it takes years of practice and people make their whole careers off of this skill. so, don’t be too tough on yourself and keep practicing. 

Now, go enjoy commenting on other people welding videos. You’re now one of us. Gooble gobble. You’re forever doomed to notice all of the crappy welds in the world. This makes amusement parks extra exciting. While you’re there, practice squirting ketchup on your hotdog like a weld bead. Good luck!

Here’s the video for this topic: How to MIG Weld – The ULTIMATE Beginners Guide – Eastwood

As always, thank you for reading,
-Joe Dick
Media Host/Eastwood Content Creator/Honda Motorcycle Wrangler

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