Mig Welding – Boy Scout Merit Badges

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As of Feb 2012, there is a merit badge for welding for boy scouts. This is Part 2 of a short series on Boy Scout Merit Badges for welding.

There are lots of things for the scout to know, but this video is geared toward the practical exercises listed in the welding merit badge pamphlet.

The practical portion :

1. Weld initials on a plate
2. Cover a 3×3 1/4″ with weld beads
3. Weld a square groove weld both sides
4. Weld a tee joint both sides
5. Weld a lap joint both sides

This video is on mig welding with .030″ er70s6 bare wire and with 75/25 ar/co2 shielding gas.

I used a Hobart 210 mvp mig welder in this video. The mvp stands for “multi voltage plug” because it will run off either 115 volt or 230 volt power.

I have used it on both voltages and with co2 as well as 75/25, and it’s a good little welder suitable for anyone’s garage.

I am trying to use welders that are likely to be found in garages and shops and barns. That is why the first boy scout video on stick welding featured a little red lincoln tombstone welder.

Setting the wire speed

There are several ways to set the voltage and wire speed settings on a mig welder.

All of them require you to weld on some scrap while setting the machine.

Straight up trial and error works, but sometimes burns up tips if you are way off.

Setting both dials at the mid point is not a bad way either, but is often pretty far off.

The best way is to use the chart on the inside of the welder (if it has one).

The Hobart 210mvp has a chart that is pretty darn close to what I would set the machine without using the chart.

I know, because I used the mid point method and then tweaked the settings until it looked and sounded right to me… then I looked at the chart and guess what? It was set to exactly what the chart recommended.

If you look at a weld calculator, settings are usually listed in voltage and wire speed in inches per minute. But dials on mig welders are not all configured like that.

For 1/8″thick steel, about 18 volts and about 250 inches per minute of .030″ wire are called out.

So that’s why it’s best to use the chart if there is one.

Otherwise, you can figure inches per minute by pressing the trigger on the mig gun for 6 seconds, measuring the wire that came out in inches, and adding a zero.

For example, 25 inches would be 250 inches per minute.

People hear me say this and roll their eyes, but it works. Wire speed drive motors are all different… but a ruler does not vary from one to the other and never needs calibration.

Once you have wire speed set, it’s just a matter of adjusting voltage up or down to achieve a smooth metal transfer and frying bacon sound with little or no spatter.

( As always, feel free to visit us at our sister site, WeldingTipsAndTricks.com. )

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