Setting Amperage on Diversion 180

[etornick]

I am a hobbyist using the Diversion 180. I was wondering why it is necessary to set the amperage on the unit to the thickness of the material. I assume that the amperage you set would be the max amount if you stepped on the pedal all the way. If I set it to the max amps (180) then if the material I am welding is not 3/16" thick all I need to do is not press the pedal all the way down. I watch the puddle and press down based on how the puddle looks. Is this wrong to do? I was thinking that perhaps by setting the max thickness it makes the pedal have finer control over the amperage but other than that is there any problem with just setting the amperage to the max and controlling it with the pedal based on how the metal is melting?

[coxey2]

setting

Aluminum needs more amperage to bust through the oxide layer thus needing more amps at the start. Aluminum needs less amps at the finish of the bead/edge of work; if its too hot at the end the bead will suffer insufficient crater fill...