Learning to arc weld

One thing I never really got around to learning in high school or in university was how to do a decent job with an arc welder. It's about time to change that- Sunset Chaser's trailer needs work, our weird new Starwind 860 will need a custom trailer, and there's always plenty of stuff that needs fixing.

It's one thing to read about how to do it- friendly old Google offers up 1.58 million pages on the subject. And, having been through engineering school, I have a pretty good idea how a weld works, what a good one should look like, and how the stresses are transferred across it.

Friends who know, though, always respond with "Well, you can read all you want, but the only real way to learn it is to lay down dozens of really bad welds until you start to get the hang of it."

So, for anyone else who's thinking of learning how to weld and is a bit intimidated by the idea, here's my "Day 1" report- complete with terrifying photos of beginner screw-ups.

The Tools

Fancy new welders are expensive. I might get one of those when I know more about it, but for now, a used 100-amp Lincoln Weld-Pak is just the ticket.

The Lincoln is a flux core wire feed type, arguably the easiest kind of arc welder to use. I tried a little bit of work with a traditional stick welder once, and have no intention of going back to that now that I've discovered wire feed. Gas shielding, i.e. MIG type, is the next step up, giving cleaner welds (less spatter) and more versatility (it can, with practice, work on a wider variety of metals). I think it's not worth the extra cost and complexity until you actually need it.

If you're new to welding, a small wire feed machine like this is an ideal starter unit. It has the distinct advantage that, since it requires only a standard 120 volt outlet, you don't have to re-wire your garage to plug it in. I'd skip the el-cheapo imports; a used Lincoln, Miller or Hobart costs about the same as, and will last longer than, a bargain bin no-name unit.

You'll also want an auto-darkening helmet (seriously, skip the old flip-down things and spend the $50 on a modern one), long leather gloves, some wire brushes, and a fire-retardent jacket to protect you and your clothing. If you don't already own an angle grinder, a good 4.5" or 5" model will come in handy.

The First Hour

So you get your welder, you put on all that protective gear, you fire it up, and start to lay down beads on some scrap steel:

Ouch.

Well, let's try holding the torch straighter, moving it more evenly, and timing our trigger pull to be just after the wire touches the work. A few more beads and perhaps we're ready to try a fillet weld between two pieces of steel:

Cutting it open is the best way to see whether you got it right. In this case, penetration isn't too bad, but the bead profile is horrific.

Or, in some places, the bead is more porous than Swiss cheese. Not cool. That's the result of an unsteady hand on the torch- the distance from tip to workpiece wasn't constant, and the feed rate was all over the map.

Here, I missed the centre of the joint by a couple of millimetres. The weld metal flowed into the joint, but there wasn't enough heat left in it to finish the job. A quick pass with the angle grinder reveals the resulting crack.

Getting better.... these fillets aren't great, but there are a few short stretches where they aren't showing too many flaws.

This bead's a little too big in places, and the start isn't very clean, but we're getting closer....

The bead profile still leaves something to be desired, appearance-wise. Upon cutting it open, though, it looks like I'm starting to get the hang of aiming the arc into the joint- the weld penetrates most of the way through the steel.

Still ugly on the surface, but as the hour progresses, there are fewer and fewer problems visible in the cut-away beads.

Let's try multiple passes, a technique that's sometimes necessary when welding very thick steel.

Holy spatter, Batman, but at least the beads are starting to look sort-of clean.

How about we try something that requires more complicated hand motions, like a fillet around a 25 mm rod?

I probably should have pre-heated that.

The fillets are starting to look a bit more like fillets, though.

And I'm starting to get the hang of using the current control knob to change the bead size and penetration. (100 A on the left, 30 A on the right.)

At the end of the hour (or was it two?), the bit of scrap looks downright awful, but I'm reasonably confident that, in due time, I'll be able to learn this skill well enough to build something useful.

I am pretty sure that anyone with steady hands and a bit of patience can learn how to arc weld. Just decide you want to learn, read up a bit (or, better yet, sign up for a 3-month night class), spend some time getting used to it on scrap steel, then go build something cool.

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