VIDEO: MIG Welding in Practice

In this video, I'm going to go through from start to finish the organization and setting up of the welder for a MIG weld

So just so you can see how it all works and how I go through the steps

So if you come and look here, I've got something set up here. It's a mock-up

It's not an actual part that I care about, but I have treated it the way I would a precious part

So there's two pieces of metal here. There's one that's upright and then one on the side

I've cleaned the surface where the weld bead is going to be, but can you also see I've put a groove in here

And that's by grinding an angle, 45 degree angle, on the two mating edges

That's going to give the weld pool a greater surface area to bond to

because we don't just have the flat surface, but we've also got the grooved surface

So we have more surface area for the weld, and also the weld is going to be a little bit lower, a little bit shallower

because now it has a depression to fit into. So I'm just going to pretend that this is a normal weld and this is how it works

My first step is to just get my cables organized. As you remember, there's two cables for every kind of electric welder

There's the ground cable and then the actual gun that's going to do the welding

Now I've got another piece of metal here too, because I never ever just jump in and weld a piece of metal that I care about

unless I test the welder, because there are settings, which I've discussed elsewhere in the course

they're crucial settings, and I want to see how this is going to work before I commit to this

because I want the weld to look nice. So my first step is to just put on the ground clamp

Now I'm going to switch on, and this particular welder, it's a little more sophisticated than the simple ones

and it can help you to decide if the settings are correct

This is step one, the MIG process with 25% carbon dioxide. That's the shielding gas I'm using, so I like that

I like that setting, and I press to select. This is the setup here, the positive and negative polarities on the various cables

So I rarely have to change that, so I'm going to press to accept

Now the diameter of wire that I'm using is 25 one thousandths of an inch

so that refers to the diameter of this wire here, the actual welding wire

So once again, I don't change that too often. Now is where we get into a more precise setting

So this thickness setting refers to the thickness of the metal I'm going to be welding

and you know, I can go quite thin, up to 5 sixteenths. So it's a quarter of an inch, so I'm going to choose that

And the machine, you can see, has already set itself up for 320 inches per minute

That's the travel rate of the wire out of the gun, and 19 volts, which has to do with the intensity of the arc, so how hot it is

We want it to be hot enough that we get good penetration of the metal, but not so hot that it burns through

or it causes the wire to melt faster than it's coming out of the gun

So notice here that there's a red sections and green sections, and both of these settings are in the middle of the green section

That's because that's the best guess of this machine for what I need

Now within those parameters though, depending on what I find here when I do my test weld

I can give it more wire speed feed within that range, or less, within the green range

And the same with the arc intensity, the voltage. I can crank it up, or I can crank it down

And technically it's supposed to be within the green range, and that works 99% of the time

Very occasionally, I will go a little bit outside the green zone when I'm adjusting

but right now this is good. We're going to start. Just before I go on, I'm going to grab a pair of wire cutters here

It's not unusual for a little bit of extra wire to come out. That's way too much to start with, so I'm just going to snip that off

and then we're going to lay down a test bead and see what it looks like. So here I've just struck the arc, and there's two things I want you to notice

First of all, I'm not rushing as I draw the welding gun across the workpiece

and I'm also going back and forth to make the bead wider than it normally would be

if I just pulled it along. And the result is a nice even weld that's complete and strong and ready to go

So now we're on to the real thing. So that went well

It's a nice neat weld. It's a little narrow here for my liking

but structurally there's no issues, especially since I did that that v-grooving before

Nice and clean, and if you take it out here, you can see there's good penetration

So it's a nice strong weld. If this was a part that really mattered and I had the opportunity

I would probably run a bead in there as well too, just to get it from both sides

But that's the MIG welding process in a nutshell