For the blokes who want to know how they work.

Plasma is the fourth state of matter.
Heat a solid and it becomes liquid.
Heat a liquid and it becomes a gas or vapour.
Heat the vapour and it changes to a plasma state.

This folks is very hot. How hot? 60,000 degrees hot. Your metal does not burn, it vaporizes.I was told in training that this is hotter than the suns temperature.
In your oxy bin or on the floor there is a degree of solid slag residue left over. In a plasma operation most ( not all ) of the metal ends up as vapour with some fine solids on the floor.

This means if there is any nasties there you can end up breathing them. Its not a real issue with mild steel as far as I am aware but you never know. Tis best to err on the side of caution and wear a respirator.

Plasma will cut steel,stainless steel,aluminium and non other conductive non ferrous metal.

The plasma is generated by a very high voltage arc being pushed at super velocity with air pressure through a pin size orifice. When the air supply is contaminated with a moisture, oil or rust the tiny particles smash against the orifice and enlarge it at an astonishing rate.
This is why the air supply has to be filtered with a micron sized filter.

Cutting with a plasma is much quicker than with oxy . Manual models are used as per an oxy cutter with much the same hand position and action. Most of them sit up on a skid at a set distance from the plate to be cut. They require an earth just like a welder. After that it’s a press of a button.

The cut quality ranges from fair to good. On some cuts it tapers from large to small from the top to bottom and then swaps back at times to tapered to straight. Mind you I have not used a good one for several years now so the kerf situation may well have changed.


In the mid 80’s I used one mated to a high speed profile and have cut at over four lineal miters per minute. I am sure the that figure is improved since then.

Some specialized plasma systems can be linked to run on computer controlled cutter. There are sheet metal shops that specialize in plasma cut patterns for wrap around pipe lagging insulation work and they are amazing to see at work.They are CN drawn from the pattern entered on a computer.

If some one indicates they would like to see one I shall even round up an diagram for it.

Grahame