Dry the air first
Compressed air carries water, and water in a plasma torch makes the arc wander, leaves dross on the underside and destroys electrodes and nozzles within an afternoon. A water separator is the minimum; a coalescing filter or small dryer is better. Drain the compressor tank regularly — that is where the water collects.
Let post-flow run
Air continues after the arc stops to cool the nozzle and electrode while they are at their hottest. Machines with adjustable post-flow should be set generously; on machines without it, simply do not switch off at the wall the moment you finish a cut.
Know what worn consumables look like
A nozzle whose orifice has gone oval or enlarged gives a wide, angled, dross-heavy cut. An electrode with a pit deeper than about 1 mm (0.04 in) in its hafnium center is finished. Both wear together and are usually replaced together.
Do not idle the pilot arc
On pilot-arc machines the arc burns between the electrode and the nozzle when it is not transferred to the work — the exact pair you are trying to preserve. Strike, transfer, cut, release.
The questions welders ask
My cuts have become slow and dross-heavy. What first?
Consumables, then air. Change the nozzle and electrode — they wear gradually so the decline is easy to miss. If that does not fix it, check for water: crack the drain on the separator and look. A machine fault is the least likely explanation.
How long should consumables last?
It depends entirely on air quality and technique. With dry air and correct standoff, a set of consumables lasts a long working session or more; with wet air, an afternoon. That difference is the argument for spending on air treatment rather than on a bigger machine.
Last reviewed 2026-08-14
