120-Volt Mig welder.

[MinnesotaDaveChalmers]

Sodo - looks like you dialed it in pretty darn good for your machine.
Were you able to get the knife edge to fully melt or did a straight line remain?

As I understand it, reducing wire speed makes the joint 'hotter' as well as increasing voltage.

The very short version:
Voltage sets the arc length and resulting bead profile.
Wire feed speed sets the welding amperage and penetration.

It's all about the proper balance of voltage to wire feed speed.

For example, I was building some gates for a customer this weekend out of his old galvanized fence pipe, the recommended setting had a little too much voltage so it would try and blow out the thin edge of the t-joints.
Dropping to the next recommended setting down fixed the voltage issue, increasing my wire feed speed a little gave me the penetration needed.
(the recommended settings on my machine are for an input voltage of 230 volts AC, my electrical service provides 244 volts AC - so they tend to be a little hot - normally just turning down my WFS fixes the problem on thicker metal)

From Miller:
1. Material thickness determines amperage. As a guideline, each 0.001 inch of material thickness requires 1 amp: 0.125 in. = 125 amps.

2. Select proper wire size, according to amperage. Since you don't want to change wire, select one for your most commonly used thicknesses.

* 30-130 A: .023-in.

* 40-145 A: 0.030 in.

* 50-180 A: 0.035 in.

* 75-250 A: 0.045 in.

3. Set the voltage. Voltage determines height and width of bead. If no chart, manual or specifications are available for setting the correct voltage, you can try this: while one person welds on scrap metal, an assistant turns down the voltage until the arc starts stubbing into the work piece. Then, start welding again and have an assistant increase the voltage until the arc becomes unstable and sloppy. A voltage midway between these two points provides a good starting point.

There is a relationship between arc voltage and arc length. A short arc decreases voltage and yields a narrow, "ropey" bead. A longer arc (more voltage) produces a flatter, wider bead. Too much arc length produces a very flat bead and a possibility of an undercut.

4. Set the wire feed speed. Wire speed controls amperage, as well as the amount of weld penetration. A speed that's too high can lead to burn-through. If a manual or weld specification sheet is not available, use the multipliers in the following chart to find a good starting point for wire feed speed. For example, for 0.030-in. wire, multiply by 2 in. per amp to find the wire feed speed in inches per minute (IPM).

 

[Sodo]

Sodo - looks like you dialed it in pretty darn good for your machine.
Were you able to get the knife edge to fully melt or did a straight line remain?

Hi Dave,

I didn't do any dialing in, just set it and welded. I had just a few minutes yesterday at my shop in the woods, and had to hustle. Plus I didn't want to waste my materials stock out there but its worthwhile if 120v discussion is now legalized.

Here's a pic of the backside. Thanks very much for the 120v tips they are appreciated!

 

[MinnesotaDaveChalmers]

Hi Dave,

I didn't do any dialing in, just set it and welded. I had just a few minutes yesterday at my shop in the woods, and had to hustle. Plus I didn't want to waste my materials stock out there but its worthwhile if 120v discussion is now legalized.

Here's a pic of the backside. Thanks very much for the 120v tips they are appreciated!

That's looking pretty good - almost fused the whole root.
It gets mostly second nature to watch for the root to fully fuse while you weld.
When it's fused like that, without visible straight lines of the parent metal, you're good to go.

When you bend it, if the machine didn't have the power to penetrate into the base metal, the weld will tear out of the v-groove in some areas.
In extreme cases, the weld will pop out of the groove on one side and it will come apart.

Edit: forgot to add - a bend fixture isn't really needed for home use, just a big vise and a good size adjustable wrench will bend it 90 degrees and check it pretty well. That's what I do when I quick check a student's welds. Sometimes they just break apart.

 

[dragoneggs]

Sodo - looks like you dialed it in pretty darn good for your machine.
Were you able to get the knife edge to fully melt or did a straight line remain?




The very short version:
Voltage sets the arc length and resulting bead profile.
Wire feed speed sets the welding amperage and penetration.

It's all about the proper balance of voltage to wire feed speed.

For example, I was building some gates for a customer this weekend out of his old galvanized fence pipe, the recommended setting had a little too much voltage so it would try and blow out the thin edge of the t-joints.
Dropping to the next recommended setting down fixed the voltage issue, increasing my wire feed speed a little gave me the penetration needed.
(the recommended settings on my machine are for an input voltage of 230 volts AC, my electrical service provides 244 volts AC - so they tend to be a little hot - normally just turning down my WFS fixes the problem on thicker metal)

From Miller:
1. Material thickness determines amperage. As a guideline, each 0.001 inch of material thickness requires 1 amp: 0.125 in. = 125 amps.

2. Select proper wire size, according to amperage. Since you don't want to change wire, select one for your most commonly used thicknesses.

* 30-130 A: .023-in.

* 40-145 A: 0.030 in.

* 50-180 A: 0.035 in.

* 75-250 A: 0.045 in.

3. Set the voltage. Voltage determines height and width of bead. If no chart, manual or specifications are available for setting the correct voltage, you can try this: while one person welds on scrap metal, an assistant turns down the voltage until the arc starts stubbing into the work piece. Then, start welding again and have an assistant increase the voltage until the arc becomes unstable and sloppy. A voltage midway between these two points provides a good starting point.

There is a relationship between arc voltage and arc length. A short arc decreases voltage and yields a narrow, "ropey" bead. A longer arc (more voltage) produces a flatter, wider bead. Too much arc length produces a very flat bead and a possibility of an undercut.

4. Set the wire feed speed. Wire speed controls amperage, as well as the amount of weld penetration. A speed that's too high can lead to burn-through. If a manual or weld specification sheet is not available, use the multipliers in the following chart to find a good starting point for wire feed speed. For example, for 0.030-in. wire, multiply by 2 in. per amp to find the wire feed speed in inches per minute (IPM).

View attachment 387946

View attachment 387945

Thanks Dave... good stuff! What I was trying to say/ask is if it is true that slowing the wire speed makes a hotter join (less cold lap)? I realize voltage and travel speed are factors but assuming those being constant.

 

[MinnesotaDaveChalmers]

Thanks Dave... good stuff! What I was trying to say/ask is if it is true that slowing the wire speed makes a hotter join (less cold lap)? I realize voltage and travel speed are factors but assuming those being constant.

I don't think I would put it that way - lowering wire feed speed lowers the welding amperage and lessens the penetration.
I'm a firm believer in adjusting volts and amps for the proper balance.

My reasoning:
1. for a particular metal thickness and weld position, a proper range for amperage can be determined
2. for each wire size the wire feed speed gives the welding amperage desired
3. the voltage gives the weld profile desired at that amperage - more volts makes it wider and wetter until it becomes spattery and unstable and/or undercuts

The amps and voltage combined give the desired result - a little tweaking here and there is expected.

Is that closer to what you were looking for?

 

[dragoneggs]

I don't think I would put it that way - lowering wire feed speed lowers the welding amperage and lessens the penetration.
I'm a firm believer in adjusting volts and amps for the proper balance.

My reasoning:
1. for a particular metal thickness and weld position, a proper range for amperage can be determined
2. for each wire size the wire feed speed gives the welding amperage desired
3. the voltage gives the weld profile desired at that amperage - more volts makes it wider and wetter until it becomes spattery and unstable and/or undercuts

The amps and voltage combined give the desired result - a little tweaking here and there is expected.

Is that closer to what you were looking for?

Gotcha... thanks.

 

[Big Barn]

Gotcha... thanks.

Yes. Nicely explained, Dave. Thanks.

Terry

 

[KubotainNH]

Dave, that's some good info there. I may need to print this. Thanks.

 

[Sodo]

When you bend it, if the machine didn't have the power to penetrate into the base metal, the weld will tear out of the v-groove in some areas.
In extreme cases, the weld will pop out of the groove on one side and it will come apart.

OK here's how the 3/8 thick test plate (welded with 120v) bent.

I bent only weld#2, the weld discussed earlier. It was very strong, had to reef on that 20T press to bend it to the 90-ish deg as shown.

From what I can see looking at weld #2 it's pretty obvious that:

---> #1 will be weaker
---> #3 will be stronger

But even though weld #2 was not 100%, it would not let trailer parts loose on the highway, it was firkin' strong.

 

[paulharvey]

Very nice.