Plasma cutters cut so easily they seem like magic; even their name sound like something from a science fiction story. But they are real, and in the past 15 years the prices have come down to the point that nearly every shop has one, from the hard working professionals to the weekend warriors. In order to keep your plasma cutter working like a high tech X-acto knife, and not a rusty hatchet, you need to periodically replace the consumables to keep the arc consistent and the air focused.
What Are Consumables?
When talking about plasma cutter consumables people usually mean just 2 parts: the nozzle and the electrode. But there are other parts that may need replacing too like the diffusor and outer nozzle cover. Typically it’s the nozzle losing its focused jet of plasma, or the electrode producing weak spark that signals it’s time for a tune up.
Why are they consumed?
Plasma cutters can slice through thick hunks of metal like a hot knife going through butter, no joke. The plasma (super-heated, electrically charged air) which gives these tools their name is at a temperature of about 10,000° Fahrenheit, and moves at thousands of feet per second. The flow of air and electricity through the nozzle causes erosion the same way water does when running down stream. Sure the erosion is on the atomic level, but electricity flows at a much higher speed than running water, so with use it eventually wears out the precisely sized hole in the end of the nozzle.
The electrode does not have plasma running through it. The air, not yet charged or heated, swirls around it as it goes through the torch. The electrode needs this airflow for cooling so it doesn’t start to melt with all the heat coming off the end of it, where the plasma is formed. Just like the electrodes in a spark plug, there is a highly conductive core, surrounded by a lesser metal like copper. High voltage by itself will cause the erosion of the center of the electrode. Let it go too long and your torch will lose a great deal of its cutting ability, as the copper produces a lower voltage arc, and less hot plasma.
The outer nozzle, and diffusor don’t really wear the way the other 2 parts do, but it is a good idea to replace them occasionally too. A worn or cracked diffusor can cause the electrode or nozzle to run hot and wear out faster. The outer nozzle can be damaged by dropping the torch, or metal blowback into it, disrupting the air or plasma out of the gun. These parts should be replaced every ten times you replace the electrode and nozzle, even if they look okay.
Luckily, like many periodic maintenance projects, replacing plasma cutter consumables is a simple, quick and easy job on most machines. Once you’ve done it a few times it should only take a few minutes, provided you have the replacements handy already.
- Make sure the machine is off, maybe even unplugged. These machines can deliver more than 300v through you if they are on, so safety first.
- Unscrew the outer cover of the nozzle. The nozzle, diffusor and electrode should drop right out.
- Place the new parts in the torch and screw the outer nozzle back on, and you are done.
The 2 biggest things that cause quicker consumption of consumables are contamination in the air lines, and overheating the torch. Always run a quality oil/water separator on your line when using a plasma cutter, and be sure to drain the compressor tank periodically. Disposable in-line air dryers work well too, as added protection.
When cutting with your torch, working too slowly will expose the consumables to more heat, and cause them to wear out faster. Though move too quickly with your cut on thicker materials and the result will be lower quality, rough, slaggy cuts. Also make sure you are feeding the torch with enough air flow. Not only does the air provide the plasma, and the shielding/focusing, it also has to cool the electrode and the nozzle.
So in conclusion, like many other tools that make your life easier, plasma cutters require periodic maintenance. Most hand held plasma cutter torches make it easy; just a few minutes of down time are needed to do the job. The difference between a freshly tuned up torch and one with a worn nozzle and electrode can be as dramatic as being able to cut through inch thick steel, or having a hard time with 5/8”.
Consumable are not expensive either, as they are meant to be consumed. Eastwood carries all you should ever need if you bought one of our plasma cutters. A kit with 5 nozzles and 5 electrodes, plus a diffusor and an external nozzle is less than $50. The number of clean precise cuts you get, and the time you save with a well cutting machine are worth the price.
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