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A Weld of Difference

April 27th, 2017

MIG Skills Improved by TIG Failures

As a master of all conceivable types of TIG welding, I feel it is time to bless the confused and evil-smelling masses with an update on my metal-joining escapades.

A while back I got myself a length of 2″ x 1/8″ flat hot-rolled steel from Home Depot. The price was not that bad, and the metal looked surprisingly good. I needed something to practice on, and the nearest metal dealer is way down the road.

I was confused by the appearance of the steel. I’ve had hot-rolled that looked like it had lumpy black enamel on it, and I’ve had hot-rolled that had a nice matte black scale that looked like the black oxide they put on tools, but this stuff wasn’t black at all, and it was smooth. I wondered if it could possibly be cold-rolled. I’ve never had any reason to buy cold-rolled steel, so I don’t really know what it looks like.

Hot-rolled steel is steel which has been formed while red hot. It’s cheaper than cold-rolled, which is not as hot when formed. I assume hot-rolled is cheaper because it’s easier to form hot steel. Hot-rolled comes with black mill scale on it, and mill scale is harder than steel. Mill scale interferes with welding. MIG will produce useful, if ugly, welds through mill scale. It’s my understanding that stick will burn right through it, although I don’t know. TIG hates scale. The arc will wander around, and I believe the impurities cause porosity. I assume black iron oxide is less conductive than iron, so that must be what causes the arc problem.

The metal I bought did, in fact, have scale on it. I guess it was thin scale, because the metal isn’t black, but I can tell it’s there, because a flap disk bounces off of it. It takes forever to remove it.

Removing the scale has been the single most annoying thing I’ve had to do in my pursuit of TIG excellence.

I got myself a nice flap disk just for scale removal, but as noted above, it didn’t work too good. Then I tried the belt grinder. This is a 3-HP steel-eating machine that can consume a piece of angle iron like a fat kid sucking up a strand of spaghetti. The scale is too much for it. It comes off, but it’s very slow. Grinding disks work, but they gouge the work, and only a small part of a grinding disk contacts the metal, so removing scale is like using a Sharpie to turn a shoebox black.

I cleaned some pieces anyway, and I graduated from laying beads on flat metal to making fillet welds. Here’s the problem with that: when you weld one side of a piece of metal, new scale grows on the other side, so if you prepare two pieces of metal and do a fillet weld on one side, you have to descale them all over again before you do the back.

You can prevent metal from re-scaling by directing inert gas at the back side. That would require more tools and a lot of aggravation, so I’m not going to do it.

My solution is to TIG my clean metal, and then, when new scale appears, move on to MIG. The new scale isn’t bad enough to bother MIG.

If you want to avoid scale removal, buy cold-rolled, weld aluminum instead of steel, or get “pickled and oiled” steel. This is hot-rolled which has been de-scaled with acid and then oiled to keep new rust from forming.

I got a pleasant surprise from all of this. While I was struggling to learn TIG, I got a lot better at MIG. TIG takes a lot more skill, and the skills transfer to MIG. For TIG, you have to develop the ability to see what you’re doing. You have to have a steady torch hand. Same stuff applies to MIG. When I went back to MIG, I found myself producing very decent welds. I could see the puddle much better than I had in the past, and I was better at aiming the torch.

I cut two short pieces of steel, offset them a little, and clamped them together for lap welding. You see the result below. It looks better in person. Anyway, there isn’t much porosity, the welds are pretty uniform, and everything is just about where it’s supposed to be. If I put in another week, I should be able to make welds nice enough to put where people can see them. There are basically two grades of welds: display-worthy and not. Most MIG welders never get to the point where they can make welds that look good enough to be placed on the front of things.

The horrible mess behind the nice weld is a TIG weld I put down later. I cleaned everything very well, except for the underside of the top piece of metal. When it got hot, it started pumping fumes into the weld.

I bought a nice belt grinder, and while I like it a lot, the welds in it are total garbage. They look like a monkey did them. Belt grinders don’t take much stress, so monkey welds are fine, but it’s an example of the low standards most welders adhere to. I’ve seen a lot of photos of welds done by amateurs and even by professionals who aren’t primarily welders, and crap welding is the norm. I would like to do a little better than that.

My MIG welds are now better than my TIG welds. I never thought they would be this good, and I almost wonder if I should have bought the TIG welder. One of the main reasons I bought it was that TIG welds are more precise and better looking.

No! That’s insane. You should always buy whatever tool you think it is that you want. There is no such thing as a tool you don’t need.

I’m still not satisfied with my helmet. I was having a problem where all I could see was a hot weld arc and a sea of blackness. I was literally positioning the torch, flipping the helmet down, and welding where I THOUGHT I needed to be. I improved things by adding a magnifying lens and turning the shade down to the minimum, but things could be better. I’m thinking my issue may be caused by age. I don’t see contrast as well as I used to.

A couple of days ago, I had a weird experience. I’m pretty sure I welded with the helmet turned off. That means I had a shade somewhere below 5. I was protected from UV, because the glass alone will do that, but I don’t think I had any help with the glare. I saw pretty well. It took me a minute or so to realize what was going on. Now I’m wondering if I even need to turn the helmet on.

If my eyes are so bad I can weld with the helmet turned off, how am I able to drive and get around? Search me.

I finally found a really excellent Youtube welding resource. There are tons of welding videos on Youtube, but some are better than others. A welder named Jody runs a site called Welding Tips and Tricks. He fills the Internet with helpful videos that took a lot of work to create. All he asks in return is that you buy his product, the TIG Finger. This is a knitted fiberglass thing that goes over your finger to keep torch heat off of it. Very useful.

I hate to say this, but a competitor of his makes a knockoff “Finger” with a wrist strap to keep it from falling off, and I bought one. I kept dropping the original TIG Finger every time I put the torch down. Oh well. I did buy the original, so I think I’m off the hook. If you know where to get the fiberglass, you can make your own and avoid getting caught between bitter competitors.

I’ve put in all this work, and now I wonder if I should have started with stick welding. A stick welder will weld crappy metal outdoors in the wind (not suitable for MIG and TIG), and stick welders aren’t expensive. Bonus: no gas required. For some reason, people look down on stick, but I’ve seen the welds, and they look very nice. My TIG has a stick clamp, so I can learn stick whenever I choose.

One of these days I’ll do a TIG weld correctly, and you will see pictures here. I’m still working on my beer opener. I turned the end of a big Craftsman wrench into an opener, and I’m going to put it on a stainless back plate and mount it on a wall. Once that’s done, I’ll order an Swag Offroad finger brake kit for my hydraulic press (don’t ask) and weld it together so I can have one more tool I don’t use.

If you want to feel like a man and not a hopeless metrosexual snowflake, get yourself a MIG or stick welder and get started. It doesn’t even matter if you don’t need to weld anything. That’s not the point. If you can’t weld, there is something wrong with you. You need to fix it.

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One Response to “A Weld of Difference”

  1. Mumblix Grumph Says:

    Here’s another YouTuber you might like. He welds in this one but farts around in for the first thirty seconds or so.

    https://www.youtube.com/watch?v=2fUAHkUfTps