How to set your mig welding volts and wire speed

Adjusting your mig welder voltage and wire feed speed for that perfect weld is easy to do.

It is the most important part that you need to get right. If you do not do this properly it will make laying down that perfect weld very hard to do.

There are only two controls that you need to worry about. Voltage and wire speed.

A mig welding power supply is a constant voltage welding machine or CV for short. Some units have the ability to do both constant voltage and constant current.

With a mig welder the voltage is pre selected via the dials on the front of the machine. These are usually labeled as positions on the switch such as 1,2,3,4 etc... or A, B, C, D. Some machines may also list how many volts each position on the switch is. You could also check the instruction manual that came with the welder or worst case contact the manufacture for help.

Among other things such as joint preparation, welding torch manipulation, welding wire type, shielding gas type and so on. The first thing you must know how to set right is the voltage and wire speed adjustment.

The setting of the voltage and wire speed is the single most important aspect of tuning your mig welding machine or wire feed welder. It does not matter if it is a small 110 volt welder, a 240volt welder or a large three phase industrial mig welder. And also regardless of the welding wire diameter, or welding wire type i.e. solid wire, gasless flux cored wire, dual shield flux cored wire, metal cored wire. And regardless what welding state you are in, short arc, globular or spray arc welding you need to be able to adjust the voltage and wire feed speed.

Even the most simple mig welding machines have these two basic controls. The smaller units may only have a high or low voltage setting. For example there might be high and low setting on one rocker switch and then 1 and 2 on another rocker switch. This is much like on larger machines where you will have say a course voltage knob which might have the numbers 1, 2, 3, 4... and then another knob for fine voltage adjustment. So a small 90amp mig welder might have only 1-4 voltage selectable settings where a bigger machine might have say 16 or more selectable voltage settings. This all depends on the make and model of machine you have. Some machine have step less voltage control where you can dial in virtually any voltage you want.

So this brings us to the question, how do you know what voltage to use?

Selecting what voltage to run at is the key for good weld penetration and nice sound welds. The higher the voltage the hotter the weld. The lower the voltage the colder the weld.

So naturally for sheet metal work in 16 gauge (1.5-1.6mm) thickness you would want a much colder welding puddle as compared to if you were welding 1/2” (12.5mm) plate. If you were to weld on the 16 gauge metal with the 1/2” plate setting you will blow holes straight through the metal simply because the arc is too powerful and hot.

If you are an experienced welder you will know how many volts you need to use to weld certain thicknesses of metals. But for everyone else what do you do? Well one way is just to practice. The other way is to have a look at a mig welding volts, amps and wire speed chart. Some machines will have a chart on the inside of the cover of the machine showing you all these settings.

Once you have this information you can get a rough idea on what voltage to start with for a particular metal thickness.

Wire feeding speed

Now welding voltage and wire feed speed go together like two peas in a pod. And they need to be in a balanced relationship with one another.

The welding wire feeding speed needs to be adjusted to suit the voltage so that everything runs smoothly. And the way you do this is to start welding and see what the arc does.

As you weld take note of how the arc sounds and how it is welding along. 
If the wire is feeding too fast it will keep punching into the metal.  So you would need to slow down the wire feeding speed.

The opposite of that is if the wire is going to slow. And then you would need to increase the wire feeding speed.

 Here is a link to the miller welding calculator. You can also use this on your iphone an ipads, search for the miller welding calculator app in itunes.

Pictures of welding beads

Wire speed too fast

Wire speed too slow

Wire speed and voltage spot on

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