Metal Tech DIY: Why Every Enthusiast Should Have Plasma Cutter

Restoring classic vehicles has vastly changed over the years. Rusted hulks that wouldn’t get a second look are now being restored. Many need over 70-percent of the body panels replaced. While some vehicles are candidates for total body replacement, others are not. With the average cost of a replacement body at over $13,000, it’s not an option for everyone.  Sometimes you want to rebuild a particular car or are deep into a project and find there was far more damaged material than first thought. This is where many projects stall.

Some of us want to do the work ourselves, create the dream ride, or save a vehicle because of sentimental value. The price of restoring a car can be a brutal dose of reality with the average cost of a professional restoration running $50,000 or more.

Equipment manufacturers have made it easier for the DIY’er by building products that are better and more compact like plasma and welding systems that are the size of small suitcases. These systems are easy to set up, lighter, and use less power. This makes them a great choice for the home enthusiast.

plasma cutter

Today’s plasma cutting systems are compact, easy to use, and affordable. This Hypertherm Powermax30 XP is a 30-amp system. It’s only 13-inches long, weighs 21 pounds, can cut up to 1/2-inch of any kind of metal, and plugs into a 110 outlet.

One Step At A Time

Panel replacement can seem intimidating, but you don’t need a degree in mechanical engineering to remove rusted metal panels and install new ones. Requirements? The right tools to do the job: a welder, maybe a plasma cutter, clamps, die grinder, and some specialized hand tools. The main ingredient to the successful panel replacement? Patience while working and the ability to do some research.

We’re here to help you understand the fabrication end of restoration, whether you want to do the work yourself or understand the process if someone is doing the work for you. If you’re looking for a project car, this series can help you to see what’s in store if your project needs metalwork and find a project vehicle that is best suited for your skills and budget.

plasma cutter

These cuts were made using a plasma-cutting system. Note, the crisp, clean edges. Modern plasma cutting is precise and when done properly, requires minimal grinding or trimming.

Not Your Grandfather’s Plasma Cutter!

Plasma systems have improved greatly over the years. Today’s plasma cutters are not only smaller, lighter, and much more powerful. They do a much better job of cutting and are more energy-efficient.

Plasma vs. Torches

While oxygen/acetylene fuel is still used for heating metal to forge or remove stuck parts, plasma systems have quickly become the industry standard for most cutting. Plasma is quicker, cleaner, safer, and affordable. The cost of a plasma system is comparable to or less than a MIG welder. Plasma cut edges are cleaner and require less grinding. There’s no preheating, just turn on the machine and cut. Plus, the heat-affected area is very small, allowing for minimal, if any, distortion.

Understanding Your Plasma Cutting System

The plasma’s cutting arc is created when compressed air is forced through a small nozzle inside a torch. A power supply produces an electric arc that is introduced to the high-pressure flow of air. This creates a “plasma jet” which can reach temperatures up to 40,000 degrees. The plasma arc will quickly slice through metal and blow away any molten material.

Common Questions About Plasma Cutters

What size air compressor is needed?

When buying an air compressor, the general rule is, always to get more cfm (cubic feet per minute) than you think is needed.  Manufacturers recommend getting a compressor that is rated 1.5 times the cfm of your plasma cutter. A 30-gallon compressor, rated at 5 cfm, will work for most portable plasma systems.

When looking to buy a plasma system, keep the cfm capacity of your compressor in mind. If you’re making small cuts, a smaller compressor should be able to keep up. Most of the cuts you’ll make will be small to medium-sized.

plasma cutter

Make sure you have clean air going into your plasma system. Moisture in the compressed air can change the chemistry of the air as well as damage the consumables of your plasma system. This photo shows two ways to make sure your air is dry and clean. The Powermax45 XP (shown) has a water separator built into it. If your system doesn’t, make sure to mount a water separator near the machine.

How do I hold the torch?

With most plasma systems, place the torch directly against the metal surface at a flat/90-degree angle. Then, pull the trigger and drag the torch across the work surface. Using a plasma system is easy, but the techniques to use the systems can vary. Most plasma-system manufacturers will have training pages on their websites with videos and instructions on how to use the equipment.

While cutting the quarter panel off of a 1969 Camaro, the torch is held against the surface at a 90-degree angle. Using a cutting guide helps keep the cut line clean and sharp. I’m also wearing tinted safety glasses designed for plasma cutting.

Do I have to wear eye protection?

Wearing the properly tinted protective lenses will not only protect your eyes but also help you see the arc as you’re cutting. Some people use tinted glasses or shields made specifically for plasma cutting. Others use the plasma cut setting on their digital welding helmets. Don’t make the mistake of trying to simply close your eyes or turn your head away for a quick cut or pierce. Besides flashing your eyes, you also can make a mistake in your work by not carefully watching as you cut.

How thick can a plasma system cut?

Most portable systems for use in automotive can cut up to 5/8-inch metal. That’s thick enough for just about any tasks in your shop.

Myths about Using Plasma Systems

Myth 1: Plasma is only for cutting

Plasma systems are versatile tools. They cut, pierce, and bevel metals of all types, shapes, and sizes. But, did you know plasma can also gouge and even remove spot welds? Systems with a gouge setting are a little more expensive, but the gouge setting does something not many tools cannot do—precisely carve away specific areas of metal. The gouge setting turns the laser-like plasma arc into a fat, softer arc. During use, the torch is held at a flatter angle, and it “washes” away the metal. Need to remove a weld or bolt head on a frame? The gouge arc carves away as much, or as little, of the weld or metal without burning through.

To remove spot welds, use an angled feathering technique. Carve around the spot weld on the top layer of metal, without damaging the bottom layer. It’s easier and quicker than traditional spot weld removal methods. Just set the system on the lowest amps and air pressure, and use a triggering technique to start and stop the arc. Place the torch at an angle next to the spot weld. Heat the metal until it starts to “blow” away from the surface. Then stop the arc, allowing the metal to cool. Then repeat until there’s a circle of removed material around the spot weld. Triggering allows the metal of the top layer to cool enough so that the bottom layer is unaffected.

Check out the shiny groove in the top half of the photo. It was carved into the surface using the gouge setting. The bottom half shows spot welds being gouged on a Camaro trunk floor. Note how the metal of the frame rail under the trunk floor piece is not damaged by the gouging.

Myth 2: Plasma will only cut stainless steel

Plasma systems will cut any kind of electronically conductive metal. Plasma’s ability to cut stainless steel and aluminum is one of its primary advantages over oxy-acetylene cutting, which is not effective on these materials. Plasma is more effective at cutting painted, dirty, or even rusted steel, which makes it an indispensable tool for anyone working on cars.

Myth 3: A plasma cutter is for big shops or production facilities.

If you’re an enthusiast with a home shop, how do you cut your metal? Do you use a cut off wheel, air shears, or a nibbler? Some situations are better suited for those methods, but for quick and versatile metal cutting, you can’t beat a plasma cutter. Once you get a plasma system, you’ll find you use it more and more.

Here I’m doing a freehand cut. Look how clean the edge is. Steadily moving the torch, at an even speed that best suits the material thickness, will help obtain a clean edge that requires minimal post-cut grinding.

Getting the Most From Your Plasma Cutting System

In addition to cutting guides, many manufacturers offer accessories that expand the kind of cutting that can be done. Check to see if there are specialized tips and nozzles for your system. Companies offer consumables that are designed for specific tasks, like gouging, high-precision cutting, limited-access cutting, and flush cuts.

I’m using Hypertherm’s HyAccess extended consumables which have a very narrow torch tip. Extended consumables are mostly used for cutting in tight spaces. Know the accessories that are available for your plasma system to get the most from your system.

Making Parts

If you can make a template for a part you need, you can make that part! One of the advantages of plasma cutting is being able to easily cut metal thicker than sheet metal. Create structural components and frameworks. Need to make some bracing or brackets? Draw out the pieces you need on cardboard or poster board, then transfer the shape to the needed thickness of metal. Cut out the parts, clean up any rough edges, and weld the part together. The quickness of plasma cutting makes it easy.

Molly Gursky of Driven Restorations creates a patch panel for a project. Molly uses plasma for many fabrication tasks in her shop.

Get the Right System for your needs

Choose the best system for your needs. Many times, people make equipment decisions based primarily on price. Any plasma system will cut, but it’s the quality of that cut that is the difference between a machine that gets used all the time and one that simply takes up space in the shop.  A machine that makes ragged cuts might not get much use.

Plasma systems allow you to quickly make all kinds of parts in any needed shape. Here we use a coffee can to cut out a circle of 1/4-inch plate.

Accessibility

Build or buy a cart for your plasma system to keep it handy. Keeping your plasma system readily accessible helps you to get the most out of it. Store all plasma related items in one place, so you can quickly find things. This will make it easier to grab gloves, glasses, and any consumables you might need.

Consumables

Sometimes a system doesn’t work like it should because of something very simple. The electrodes and nozzles tend to wear out with use, so have replacements on hand. If the system is not working like expected, check the torch and see if something needs replaced. Electrodes and nozzles are inexpensive.

A Place to Cut

Having a fabrication table can make a big difference if you want to use your plasma system to create patches or repair things. Having a rolling metal table with a vise attached gives you the best place to get the most out of your plasma cutter and your welding machine. Make one yourself, find a used table online, or buy a kit.

This is a fabrication table we got at a farm sale for $65. It even came with the vise. Check your local online classifieds if you’re looking for a metal table. Farm sales are great places to find all kinds of shop equipment.

If you’re interested in getting a plasma cutting system, do your research, don’t make an impulse purchase. Look at reviews, and find the right system for your needs. A good system will last a lifetime and save you many hours of frustration. If you find a good quality system you like but the cost is too high, find a used system with few hours on it.

Car projects should be fun!

At the end of the day, it comes down to one thing: the rate of enjoyment while working on your project. Often, we focus too hard on the outcome, when we should be enjoying the journey. Having good equipment that gets the job done efficiently makes the work go easier. Next time, we’ll take a close look at welding systems. We’ll explain the different kinds of welding and examine welding systems that are easy to use and help newbies get professional results.

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About the author

JoAnn Bortles

JoAnn Bortles is an award winning custom automotive painter, airbrush artist, certified welder/fabricator, author, and photo journalist with over 30 years of experience in the automotive industry.
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