I bought a new miller welder and the Mig Gun Nozzle grounds out and arcs when it touches the work piece. I'm running solid wire with shielding gas and the polarity is set up correctly. Almost seems like an insulator is failing.
First thing to do is to take the nozzle off and clean it. There might be spatter inside that's shorting between the gas diffuser and the nozzle.
Otherwise, the insulator is bad and needs to be replaced.
Some MIG machines have a separate insulator and nozzle, newer ones have the nozzle + insulator as one piece. Should be able to get new ones at any local welding supply store. Or, order the parts online.
Does it do this all the time, or only when you're pressing the trigger? If it happens even when you're not holding the trigger, then you may also have a bad contactor.
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