Best Plasma Cutter Guide for 2019 & Plasma Cutter Reviews
- 1 What is a Plasma Cutter?
- 2 Why use a Plasma Cutter?
- 3 How to Set up your Plasma Cutter?
- 4 What to look for in a plasma cutter
What is a Plasma Cutter?
A plasma cutter is a machine that allows you to easily cut through any conductive metal including aluminum, stainless steel, copper, brass, steel and more. The plasma jet is formed by forcing gas through a nozzle in the torch and combining it with an electric arc generated from the power supply. This reaches temperatures of up to 40,000° F and can instantly melt and cut metal.
Why use a Plasma Cutter?
Plasma cutters are the best way to cut metal. They cut much faster than oxy-fuel and are more precise due to a smaller width of cut. This means the surrounding area is not affected by the heat and you can be more specific with the area of the cut. Plasma cutting can also cut any conductive metal, including stainless steel or aluminum so it’s a versatile option.
How to Set up your Plasma Cutter?
- Follow all the safety instructions issued in the handbook, including wearing a helmet to protect your eyes from radiation and welding gloves.
- Connect the air compressor to the plasma cutter (see instructions as the way to do this varies). If your plasma cutter has a built in air compressor you won’t need to do this.
- Connect your cutting torch to the plasma cutter
- Connect your ground clamp to the plasma cutter and securely attach it to the work piece. Ensure that there is no rust or paint where the clamp meets the work piece.
- Ensure all the connectors are firmly attached
- Set the correct settings for the metal thickness you’re cutting.
- Test the torch to see if there is air flow by briefly holding down the trigger on the torch.
- If there is air flow – move the torch head onto the metal work piece to cut the metal.
What to look for in a plasma cutter
The number one thing you should look at when you choose a plasma cutter is the thickness of metal that it cuts. You should consider what thickness of metal you’re going to be working on the most frequently and look for an ideal cut at that thickness. Consider the thickness of mild metal that the machine can cut at a rate of 10 inches per minute. The severance cut will not produce as good results and you’re better off only using this maximum thickness occasionally and where you don’t mind dross. If you require quality cuts then you should look at the ideal cut.
The severance thickness is the maximum thickness that the plasma cutter can cut through metal, however, this requires an edge start to effectively cut the metal. At the severance thickness, the cut will be very slow and the machine won’t produce sufficient heat for a clean cut and will be rough and dross filled. Cutting metal at the severance thickness is not recommended for regular cutting or achieving the best results.
Built in Air Compressor
Most plasma cutters will require you to use an additional air compress before you can cut with it. But there are some plasma cutters that have a build in air compressor. These are a more expensive but more convenient option as if you’re out in the field you won’t need a separate air compressor with you. You don’t need to hook up an air hose or anything, you can simply plug it in and start cutting. These are definitely something worth considering for not much extra money.
Better plasma cutters will have pilot arc as a cutting feature which means you can make a cut without the torch tip making contact with the metal. Pilot arc helps to cut through painted and rusty surfaces. Remember that if you are cutting rusty or painted surfaces you’ll need to clean the area where you connect the ground clamp. Also, if you’re going across metal with gaps between the metal such as mesh sheet, you won’t need to stop and start the torch because it stays lit with a continuous arc. Most welders except the cheap Chinese ones will have pilot arc.
Once you’ve purchased your plasma cutter, an ongoing cost will be replacing consumables. The 5 parts that are considered consumables are the retaining cap, electrode, nozzle, shield cap and swirl ring. They all have different life expectancy depending on a number of variables but when you’re piercing metal and the molten metal blows back onto the torch they’re bound to take some damage. The hole in the nozzle will need to be perfectly round or the cut will be affected. Also if the put depth increases this will increase dross and affect the quality of the cut. The more expensive welders tend to have more long lasting consumables. Even though a Hypertherm machines are expensive, they have a low operating cost due to the excellent quality of their consumables.
Price is a huge consideration when buying a plasma cutter. It’s easy to go for a cheap chinese made plasma cutter, but make sure you know the risks. The life span of a low cost machine will be much shorter than a welder that’s made in the US or is from a reliable manufacturer. Hypertherm, Hobart and Miller are dependable and excellent quality and could easily last 3 or 4 times as long as a cheap plasma cutter – which is one of the reasons they’re more expensive.
Plasma cutters that run of 110/115/120V power input are compatible with your normal indoor power source. These are great for beginners or if you’re using them at home, but they’re limited in the power they produce. If you want a bit more power you’ll need one with a 220V input, which are only compatible with generators. If you get a plasma cutter with 110V and 220V power input then you’ll have the choice of power supplies to use, so these are my favorite types due to their versatility.
The Amperage of a plasma cutter will indicate the thickness of metal that it’s able to cut. e.g. a 30A output power amperage should comfortably cut 3/8 inch metal. but a 12A output power may only cut approximately 1/8 inch. If you use a 220V power input you’ll be able to get a higher amperage and cut thicker metal.
Duty cycle refers to the length of time that the machine can continuously operate before needing to cool down. For example, a 35% duty cycle at a set amperage & voltage will mean that on those settings, the plasma cutter can remain on for 3.5 minutes out of a total of 10 minutes without overheating. Duty cycle will increase you lower the amperage. A longer duty cycle at a higher amperage is better for making long deep cuts into metal.
Weight is always something to consider when buying equipment as you don’t want to be carrying around too much heavy equipment. Luckily, most plasma cutters are relatively light these days thanks to inverter technology. If you’re buying a plasma cutter with a built in air compressor it might be slightly heavier, but this will still be a lot more portable as you only need the plasma cutter and you’re ready to go.
Last but not least you need to consider safety as your number one priority. Read all through all the safety instructions supplied in the instruction booklet by your chosen plasma cutter. Make sure you get a good pair of safety glasses to protect your eyes. Even though the arc isn’t as intense as a welding arc it can still damage your eyes so try a pair of shade 3 or 5 glasses. You should also wear gloves, I like to wear MIG or TIG gloves that aren’t too bulky and let you feel what you’re doing whilst protecting you. Don’t use any gloves made from synthetic material because they can melt and stick to your skin, always go with leather. Cover your body, legs and arms with durable, cotton material to protect it from sparks and the arc. Finally, as you’ll be chopping up metal, wear some boots with steel protection to prevent injury from falling metal.
Hopefully this guide will help you choose the best plasma cutter for your needs. If there’s anything I’ve missed please feel free to leave questions in the comments below.
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Author: John Ward
John is the founder and editor of Kings of Welding