VIDEO: Tools for Cleaning Mild Steel

In this video, I want to explain to you how I clean metal for the best possible MIG welds

Now as I've mentioned before in other videos, strictly speaking, you don't need to get back to bare metal in order for a MIG weld to work

But for it to work to its full potential and for the bead to look as nice as possible and be as strong as possible

you do need to get back to bare metal. This is a piece of black iron pipe

It's called black iron because it's black on the surface, although the actual metal

isn't really black. What you're seeing on the surface here is something called mill scale

So you can imagine this started off as molten steel and it was

extruded. Actually, this is a this is welded pipe. I don't know if you can see that, but there's a there's a weld bead in there

So it actually started off as some flat stock and it was it was bent in a factory and and welded and seamlessly welded

You can't really see the weld on this side. But during that process of heating and forming and

manufacturing, there's a kind of with a mill scale forms on the surface. It's a product of

oxygen and I guess manufacturing oils and pressures and all kinds of things and that's why this is black

Now it's starting to rust a little bit here too because it's been outside. Bottom line is that we want fresh clean steel if we can for the best possible welds and

the usual tool for that is something like this. An angle grinder with what's called a flap wheel, which is an abrasive

It removes a fair amount of metal. It does it fairly quickly in most cases

but it's not the best for this sort of thing because it actually travels so quickly like this. The maximum rpm on this disk is over 12,000

I think it probably spins at a full 10,000. I don't know if it says anywhere here

Yes, sorry 8,500. So it's really spinning very quickly and so quickly in fact that it can actually burnish the surface of the metal and

not remove the mill scale as fast as you might like or as you can

What I have found works better than that and it's nicer to use too

It's more controllable and it's more effective and that's a regular woodworking

sander. This is a five inch random orbit sander. As I said, it's meant for working with wood

but it happens to do a great job getting off this mill scale. So I'm going to show you that but before I do I just want to point out a

couple of different abrasives. This is the sort of abrasive disc that's sold most commonly for use on a five inch random orbit sander. Works great on

wood and it works pretty good on metal too, but what works better on metal is

this mesh style abrasive. So you can see my fingers through it I think and

the advantage there is that there's, well the advantage for woodworking is

that there's all kinds of holes in here and sanders like this have a built-in vacuum system, a little vacuum system. These holes

suck the dust in, trap it in this canister. So something like this

maximizes the the airflow and the sawdust pickup when you're dealing with wood

But what I have found with metal is that the open weave clogs up less. The abrasive lasts longer, quite a bit longer, than regular sandpaper type abrasives and

it just does a great job. There's probably different companies that make this kind of thing. This is made by Diablo

This grit is actually a little fine. 180 is a bit fine for what I'm doing here. 80 grit would be better

But anyway, let's let's take a look and I'll show you how it works and what clean steel really looks like

Now that is bare metal and you can see where the sander kind of worked through the mill scale

This isn't as big of a job as you might think because you really only need to do it where you're going to actually do

the welding. You know, later on subsequent steps might involve cleaning the whole thing that you've made and applying some kind of paint

But as far as cleaning metal for welding goes, that's the ticket. It's perfectly clean and you'll get really good results if you try to weld to that