A Guide to Plasma Cutters
Tom Vondrasek | 10 May 2024 | 4 minutes to read
Plasma cutters are an easy way to cut metal. It is faster than gas cutting (oxygen, acetylene) and puts less heat into the metal. This reduces distortion, especially on thin metal sheet. Because the heat is so concentrated it also allows using a pattern, allowing you to cut complex curves on metal. Note that, being electric, you can only use plasma cutters on conductive materials like metals.
Besides the plasma cutter you will need an air compressor. The plasma cutter needs the air pressure to generate plasma. You also need a filter to take out moisture in the air lines from the compressor before it goes into the plasma cutter. Moisture will cause your consumables to chew out a lot quicker than without moisture. The input air pressure you need will vary between machines and most cutters will add the correct amount of air for the cut settings you choose.
How Does a Plasma Cutter Work?
Plasma cutters work much like an electric welder. They need an electric circuit to work. They also have 2 leads, a cutting torch lead and a ground or earth lead. Power flows from the machine through the cutting torch lead, through the plasma arc, along the job and back to the machine via the earth lead. The earth lead has a clamp on it so needs to be connected to the cutting job. Make sure it is on the piece you want to keep, not the piece you want to cut off.
The cutting torch on the plasma cutter is set up to swirl air around an electrode. When the electrode is powered up it ionises or changes this air to create plasma. It does this by making the air extremely hot. It also increases the air pressure so the plasma stream that comes out of the torch is at a much greater pressure than the incoming air. The heat of it is around 25,000 degrees Celsius, where our sun’s surface is only around 5,500 degrees.
Plasma Cutter Safety
Everything that applies for welding safety applies to plasma cutting. When cutting metal, the process involves melting it and blowing it away. You need to make sure the area in which you are doing this is clear of any flammable material. Molten metal will set most things alight or damage them.
For eye protection, a welding helmet is mandatory as the intense light produced by plasma is as bad as the arc on a welder. The helmets with auto darkening lenses are a must have as not using them can cause permanent eye damage. A good set of welding leather or Kevlar gloves should also be on your shopping list. The heat on a piece of metal is hard to judge by eye and you don't want to test it with bare hands.
For clothing, avoid synthetics and a set of overalls are a safe bet. Leather shoes or work boots instead of runners or thongs for your feet. Keep the area well-ventilated as cutting can produce toxic fumes. The respirator you use for welding can be used for cutting.
Choosing a Plasma Cutter
Choosing a plasma cutter is much easier than choosing a welder. The reason is that plasma cutters will cut all types of metal, it just depends on the thickness. The thicker the metal, the more power you will need to cut through it. Power is measured in amperage or amps and the higher the amps the more powerful the plasma cutter.
For example, let’s look at the Cigweld range of cutters. The Cigweld Easycut is a 30 Amp machine that will cut up to 10mm thick mild steel. It plugs into a normal 10 Amp household power point. The CutSkill Plasma 60 model is a 60 Amp unit that cut up to 20mm thick mild steel. It needs a heavy duty 15 Amp power point.
The only other thing you need to check is compressor air pressure. You need an air compressor that can match the input required by the plasma cutter.
Welding at Repco
If you have a welder and enjoy using it for projects or a hobby, then a plasma cutter is the perfect tool to complement it. You can use the same safety equipment and clothing thereby saving money. Usually where you get you welding consumables will be where you find consumables for your plasma cutter. Items in the cutting torch will need to be replaced from time to time.
At Repco we supply a wide range of welding equipment, including Cigweld Inverter Welders, chipping hammers, welding helmets, and other PPE that will set you up safely for your next big welding job.
