A plasma cutter looks similar to an arc welder, but instead of joining metals, the job here is to cut through them quickly and accurately. We’ve been looking at the technical aspects so we can help you decide which would suit your shop. In addition to our buyer’s guide, we’ve picked a few favorites. Top spot goes to the Lotos 50-Amp model, which comes from one of the best-known names in the industry, and delivers professional-grade performance and reliability.
While other factors are important, maximum cut thickness is usually the headline figure. However, care is needed when looking at this. You should get two figures, one for “clean cut,” and a higher one for “severance cut.” The first is self explanatory — and what most will look for. The second is the thickness that the machine will cut through when pushed to its limits. However, the finish will be rough.
There’s another aspect to this, and it depends on the voltage. Most plasma cutters can adapt to either 110V or 220V power — but they may only reach their maximum cut on the higher voltage settings. It’s something worth checking, especially if you’re looking at budget machines.
Along with your plasma cutter, you’ll also need a gas or air supply. Traditionally pro shops would use argon, nitrogen or oxygen (the latter being potentially dangerous). Modern machines tend to use compressed air. If you already have a compressor you would like to use with your plasma cutter, you’ll need to check both PSI (pressure in pounds per square inch, and CFM (flow, in cubic feet per minute).
Plasma cutters generate a huge amount of heat, so they need periodic breaks to cool down. This is called the duty cycle, given as a percentage. Each model should provide information but the amps specified may not be the maximum. A 50A machine, for example, can probably run as low as 10A for cutting thin sheet. So, a typical duty cycle might read 30% at 35A, which means for every three minutes working at 35A, it needs to rest for seven minutes. Running at 20A, the duty cycle would be longer, while running flat out at 50A the duty cycle would be less. Duty cycles rarely exceed 60%, even on the most powerful plasma cutters.
Nozzles are either touch or non-touch, the advantage with the latter being that it doesn’t need to be in contact with the material. If the surface is bumpy, damaged, or has flaking paint, the plasma cutter works just like it would on clean, flat, bare metal.
Drag technology allows you to keep the nozzle in contact with the material, something that otherwise risks a double-arc (which could weld the torch to the metal). This makes it easy to follow a pre-drawn line to cut complex shapes — a popular option with decorative metalworkers.
The initial supply of electrodes and nozzles won’t last long, and this is an ongoing cost, so be sure to research in advance the price of these items for the unit you’re considering. An aftermarket supply can save money, but don’t be tempted by very cheap products that will affect performance.
Although you could find a cheap plasma cutter for less, we’d recommend spending around $250-$300 for a reliable 40A or 50A machine. There’s lots of choice in the $400-$600 range, and most people should find what they need for that kind of budget. High-power plasma cutters — 80A and up — will cost you anywhere from $1,000-$3,000.
A. If you just want to chop through thin sheet, it can be done, but you’ve got little control, and finish quality will be very poor. However, there are plasma cutter/welder combo machines available if you do a lot of both.
A. It’s a painful eye condition that happens if you don’t wear a welder’s mask. UV light damages the corneas, leading to severe irritation that can last several days. It’s a bit like sunburn to your eyeballs! So always, always put on a mask before you cut.
Our take: Powerful 50A tool offers excellent control on all surfaces.
What we like: Non-touch pilot arc is great for uneven, painted or rusty metal. 110/220 volt switchable. 3/4” severance cut. Fast, simple setup.
What we dislike: Not much. A few owners have had faults from near new units, but warranty should cover replacement.
Where to buy: Sold by Home Depot
Our take: Terrific value 50A machine for professional and home use.
What we like: Can run off 220V or 110V. It is also very compact so it's easy to carry around.
What we dislike: Instructions on how to use are a little vague, some units coming in with no manual at all.
Where to buy: Sold at Amazon
Our take: Reliable, entry-level machine from a well-known manufacturer.
What we like: Powerful enough for severance cutting up to 3/4”. Auto-adjusting voltage wherever you plug in. Surprisingly comfortable gun.
What we dislike: Nothing, but there are 50A machines for the same money.
Where to buy: Sold by Home Depot
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Bob Beacham writes for BestReviews. BestReviews has helped millions of consumers simplify their purchasing decisions, saving them time and money