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120V MIG welder question

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Re: 120V MIG welder question

Postby MinnesotaDave » Sat May 06, 2017 11:27 am

cj737 wrote:
MinnesotaDave wrote:If WFS is adjusted so that .024" and .030" wire are running at the same amperage, the higher current density could yield more penetration.

Stubbing into the weld is often due to a less than ideal ground and/or too fast WFS for the set voltage.

You are correct, IF the WFS is equal. Using 0.024 wire should allow lower voltage to yield the same penetration proportionally as 0.030 wire (all things being equal). In theory, that would reduce the amperage draw. But I would not make these changes to accommodate a electrical current draw issue. Fix the breaker, because ultimately you will overdraw the circuit.

If the WFS is equal, the .024" wire will be putting out less amperage than the .030" wire.

To output the same amperage, the WFS for .024" wire must be increased.

Then you have same amperage with different current densities and the smaller diameter wire should give deeper penetration.

Lincoln probably says it better than I do, so I looked up a quote from them:
Electrode Diameter: when welding with two different diameters of the same electrode and at the same current level, generally more penetration is achieved with the smaller diameter electrode than with the larger diameter electrode (see Figure 5). If you look at an end slice of each size wire, the smaller diameter has less cross sectional area than the larger diameter. As the same amount of current flows through each electrode, the concentration or density of current is greater in the smaller diameter electrode than in the larger diameter electrode. As a result of this higher current density, the smaller diameter electrode will have greater weld penetration than the larger diameter electrode. Note however that every electrode diameter has a maximum current density before the welding arc becomes very unstable and erratic. So as current reaches a certain level, it will become necessary to increase the electrode diameter.
Dave J.

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