How to Select the Correct Plasma Cutter
Jeff Noland of HTP
The most important consideration when selecting a plasma cutter is the thickness of the material you will need to cut. Don't just say 1/2-inch because it is a nice round number that comes to mind-get a ruler, caliper, micrometer, or some measuring device and actually measure the thickness of the material you will be working with.
An analogy I like to make is it's like buying horsepower-the more amperage you have, the thicker you will be able to cut. However, more is not always better! A higher amperage machine will have a larger plasma cutting torch to dissipate the higher heat involved with cutting thicker material. The bigger torch is bulkier and won't get into tight places.
Another consideration is cost-a higher amperage machine will cost more money. A 25- to 30-amp machine gives you the ability to cut thin sheetmetal all the way up to 1/4-inch steel. And how much cutting are you really doing beyond that? This should tackle pretty much any automotive project you would be doing in your garage.
If you move up to a 40-amp machine, it will give you the ability to cut 1/2-inch steel. A benefit of a 40-amp machine over a 30-amp machine is it will cut any given thickness faster. So if you were doing a lot of cutting in the 1/4-inch range you would be able to cut at 25 inch/min vs. 12 inch/min.
A 60-amp machine is probably at the top end of the spectrum for anyone doing automotive work. These machines give you the capability to cut 3/4- to 1-inch steel. You better be building a lot frames in your garage to cost justify one of these cutters.
Two more things to take into consideration are air consumption and power supply. Some plasma cutters will operate on 110 volts, some operate on 110 and 220 volts, and some are 220 volts only. Make sure you have the correct voltage and amperage to run the machine you intend to purchase. Don't buy a cutter and then have to spend hundreds of dollars to upgrade your electrical service.
Generally speaking, for those working in their garage, air consumption usually is not an issue. The reason I say that, is because more than likely, you won't be doing "production" cutting at home. Let's say you have a 25-amp machine and are cutting a bracket out of 1/4-inch steel and need to make a 4-inch cut. At 12-inch/min that is a 15-second cut. A 25-amp machine will need about 31/2 cfm at 60 to 80 psi. Even if you have a small air compressor, you probably have enough air in your tank to get the job done. And with cutting speeds in sheetmetal upwards of 100-inch/min, you can cut a lot of sheetmetal before your air compressor will kick in.
The Super Dry filter is attached...
The Super Dry filter is attached to the provided pressure regulator at the inlet side of the 301 plasma cutter. The regulator is adjusted to 72 psi with the inlet air attached and the trigger of the torched depressed.
Editor Manson already had...
Editor Manson already had a pair of 220-volt, 30-amp outlets in his shop so he changed the plug that came installed on the 301 to the existing style. An easy job for the average person, but if there's any doubt in your mind, consult a professional before burning your garage down!
The plasma torch is fairly...
The plasma torch is fairly simple: The electrode is at the center, and the nozzle is just below it. The swirl ring is the second from the right; it causes the plasma to turn rapidly as it passes by.
A Plasma Parts Kit is a must...
A Plasma Parts Kit is a must have, especially if you're using one for the first time as you might go through some of the consumables faster than an experienced user. The kit consists of a spare gas diffuser, two extra cutting tips and electrodes, and an extra swirl ring. We also added an extended electrode and cutting tip, useful for getting into tight corners and great for pattern cutting.
Like any kind of work in the...
Like any kind of work in the shop or garage, safety is an utmost concern. A good, heavy-duty set of welding gloves are a must have and a pair of safety glasses that are shade-rated for using a plasma cutter are necessary. HTP offers a welding helmet that features a weld, cut, and grind function that has an adjustable lens that makes it simple to go from welding to grinding to plasma cutting with a flick of the switch, all the while offering full face protection while letting visible light through at a shade of 2.75 while offering UV and IR protection to a shade of 14.
Proving he's as talented as...
Proving he's as talented as he is good looking, our fearless leader uses the MicroCut 301 and a straight edge to cut a piece of 14-gauge sheet metal to repair the front valance panel on his F-1.
The MicroCut 301 allowed a...
The MicroCut 301 allowed a patch piece to be cut accurately with a gap close enough to weld up easily.
Unlike a cutting torch a plasma...
Unlike a cutting torch a plasma cutting machine will slice through any material that will conduct electricity, which makes cutting stainless steel, copper, brass, or aluminum plate as shown here, a breeze.
The MicroCut 301 allowed a...
The MicroCut 301 allowed a patch piece to be cut accurately with a gap close enough to weld up easily.