How to Use a Plasma Cutter

When you first get into metalworking it can be pretty overwhelming. There are tons of principles and practices to learn for you to actually become good at metalworking… there are a few machines and tools you will need to master.

So I totally get it – I’ve been there and  I understand how it’s easy to become overwhelmed. The best solution I found is to learn one small thing each and every day. That way, over the course of a few months you’ll pick up a good amount of important tips, tricks, and best practices.

When you look back and discover all the things you’ve learned along the way, you’ll be amazed.

Our goal is to help you become a better metalworker. So, in this article, “How to use a Plasma Cutter,”  I’ll share my experiences and know-how that I have learned along the way. Don’t worry, even if you’ve never heard of this machine I promise you will have have a solid working knowledge when we are finished.

In this article  we will cover:
  • What exactly is a plasma cutter
  • Uses of a plasma cutter
  • How a plasma cutter works (and the science behind it)
  • Plasma cutters vs. Multi Process machines
  • Using a Plasma Cutter (specifics and details)

A plasma cutter is a great tool to have. Especially if your building or running a fabrication business. They are portable, easy to use and can really make you some quick money.

I started using a plasma cutter several years ago, and I wish I learned about them even sooner.

Before my new favorite tool came along, I would use an angle grinder and a bandsaw to make all my cuts. But now, my plasma cutter takes on all that heavy work with ease.

Additional information about plasma cutting can be read in these two additional articles on this website:

So, let’s jump in and explore the plasma cutter, how it works and the different types available on the market.

What exactly is a plasma cutter

Now, to really understand a plasma cutter it’s important to talk about the science behind it. You’ll not only have a deeper knowledge of the machine, but you’ll have a better idea of how to troubleshoot problems if and when they come up.

The Science

“ So what’s the deal – I just buy a plasma cutter, hook up the gas and electricity and I’m good to go… right? “Well, not exactly.

Plasma cutters work off of different types of gas, they could use compressed air (like your shop compressor), argon or oxygen. In this article, we will stick to hand-held plasma cutters so the majority of these machines will run off of compressed air.

Now, here is the cool part.

We all know about ice, steam and liquid water right? Yes, we are stepping back to our 6th-grade science class for a second. The ice, steam, and water represent the different states of matter we are all familiar with: Solid, liquid and gas.

But hold on a minute: there is the 4th state of matter that we rarely discuss- Plasma.

So you might ask, “How does that differ from a regular gas?” And that’s a great question. So let me answer it. One way plasma differs from a regular gas is that it has an equal number of both positively and negatively charged ions.

Whenever high heat is applied to the gas, thus turning it into plasma, it is endowed with a rather unique capability. When plasma is directed at high speed toward a piece of metal, the electrons in the plasma collide with the base metal. Consequently, the metal is literally melted and blown away in the form of a cut.

Now that you know a little about how a plasma cutter actually works, let’s talk about the setup and tools you’ll need.

The Machine and Setup

The plasma cutter itself is a pretty straightforward machine. With a basic handheld model, you have your torch and your electric and gas inputs. It’s important to know that a plasma cutter needs a supply of dry air.

Most machines come with a filter to dry and remove any impurities from the air feed. But some value machines do not. So keep that in mind. A good compressor for the shop would be this one.

For the hobbyist, a plasma cutter that can run on either 110v or  220v is a nice choice. Since 110v is available just about everywhere, this type of machine is highly portable. However, the metal thickness you can cut using 110v is limited to the much thinner stuff. Take a look at the plasma cutter the owner of this site uses, here.

Once you have your air setup and your machine is plugged in, you are ready to go. You simply mark your metal and start to cut. Keep in mind, most machines need 220v for metal thicker than ⅜” inch and above.

The biggest thing to keep in mind for the new user is this, travel speed. A good rule of thumb is the thicker your metal, the slower your travel speed needs to be. If you move too fast you’ll fail to achieve a thorough cut.

Consumables

Just like welding, there are consumables you will need to replace from time to time when using a plasma cutter. The main item that will need replacing every so often is the tip.

Some brands are designed so that you must purchase their tips. And others come with generically designed tips which are available at a much cheaper price. This is just something to keep in mind when deciding on which cutter to purchase.

How to use a plasma cutter effectively.

So far we covered a bit of the science behind the plasma cutter, the machine itself and the setup. Now let’s shift gears and talk about major uses for a plasma cutter and how to best use a plasma cutter.

You can find plasma cutters in the field and in the shop. Sometimes they are dedicated shop machines and sometimes you can use a portable machine in the shop and in the field as previously mentioned. It all really depends on your needs and the projects you want to work on. But ideally, you will want to have a dedicated shop and a separate field machine.

Field use

There are many portable plasma cutters on the market to choose from. They range in price from the inexpensive value brands to high-end models. Most of the machines are pretty solid performers. Just be wary of the bottom of the barrel machines. You will probably end up with something less than useful.

For field use, you’ll want a machine with 15′ or 20’leads. This is so you can easily reach your work and still be able to hook up your air and electricity.

You can also run a plasma cutter, or welder for that matter, off of a generator if there is no 110v power available. I’ve done this several times and it is great to know that this is an option. With a generator, you are truly 100% portable.

Typical uses

Typical use will vary and are going to be based on the projects you are doing. Therefore, let me give you some ideas about the projects I’ve used my field plasma cutter to complete.

  • Apartment renovations.

We had a project where an older building was being converted from rental apartments into condos. The designers wanted all the trash chutes and HVAC ductwork removed for a new high-efficiency system. To save time we had about 12 plasma cutters going at once( on different floors) to cut out and remove all the duct work.

  • Art Installations

Artists can be a fickle bunch, so sometimes it best to do finishing work in the field. We once had a 35’ steel figure that had to be secured into the ground and to the adjacent building. Once the artist liked the “look” of the statues support,s we had to fabricate steel anchors to fit curved metal. So, we traced cardboard along the figure to get an exact fit. We then traced our cardboard over the steel and cut the anchors with the plasma cutter.

  • Maintenance

Sometimes we come across a machine or a structure that needs a small repair. A plasma cutter can efficiently cut an odd shape or small piece of metal without having to go back to the shop. It saves time and completes a repair quickly.

Shop use

Now, shop use is a bit of a different story with plasma cutters. Plasma cutters can be used with a CNC machine and the results can be amazing. You can take a raw sheet of steel and transform it into some amazingly designed works of art.

More than just making beautiful pieces, these designs can be repeated over and over. This allows your shop to take on big orders for larger clients. Some examples I’ve seen :

  • Design and produce 79 window guards for a small apartment building
  • Produce 125 metal pumpkins for a small town Halloween festival
  • Design a metal exit door for a museum (with stain glass to be added)

This is just the tip of the iceberg when it comes to shop use with a CNC table. But the main idea is that you can produce accurate cuts over and over again. Which will be a big deal if you are looking to break into production work or have a job where you require a lot of the same parts.

 Attachments and accessories.

I would like to cover some of the attachments and other items for plasma cutters. Just in case you may not want to go the CNC route. You may have a fabrication shop or are thinking about doing some of that kind of work. In that case, some great attachments and accessories to have would be the following :

  • Plasma cutting table

Here is a good one from Eastwood. It’s very handy to have for two main reasons – 1) you don’t want to cut on the floor and 2) if you secure the metal to your welding table, the part you cut will usually fall to the floor. This table allows you to make secure cuts and supports your entire workpiece.

  • Magnetic guide.

Here is another good one from Eastwood.  Sometimes you need to make a curved cut. Especially, if you’re working on car body panels or artwork. This guide will allow you to run your torch along the edge for an accurate cut.

  • Circle kit

Let’s say you need to fabricate a steel bar, and to anchor it in place you’ll need to cut 73 through holes so you can bolt this bar in place. How can you do that easily? With a circle attachment. Or let’s say you need to cut circular disks for an art installation – well, this attachment will come in handy for you.

You can use a plasma cutter effectively in the field and in the shop. Depending on the project you may need some attachments to produce high quality work quickly and effectively. Most of the time you can purchase the attachments and tools as you go, so over time, you have a good selection of attachments to make jobs much easier.

Plasma cutters vs Multi-process machines

The major difference between a plasma cutter and a multi-process machine is this: the plasma cutter will have one function, cutting. The multi-process machine will have several functions, usually stick welding and TIG welding in addition to plasma cutting.

Who should buy a multi-process machine vs. a plasma cutter?

There is no hard and fast rule to answer this question, but it comes up a lot so I’ll give you my best answer.

If you are a DIY’er and like to weld on the weekends, then a good MP machine will suit you well. You can hook up to 110v (home power) and cut ⅜” steel without a problem. Then you can easily set your machine weld.

An MP machine is a good investment and owning one will save you space rather than owning separate welders and a plasma cutter.

If you are a small business or general contractor then it pays to have a dedicated plasma cutter. You’ll be more efficient at jobs and the savings in labor cost will pay for the machine in no time – including any special attachments needed.

Using a plasma cutter: the specifics and details

Every plasma cutter is going to operate a bit differently. Consequently, it’s always best to consult your owners manual before starting. Some like the Lincoln plasma cutters will have built-in air and safety guards. While others will need shop air and have limited safety guards. It’s always a good idea to get acquainted with your specific machine before using it.

Below are a few general points that we will cover in this article concerning how to effectively use a plasma cutter. We have broken them down into bite-sized pieces.

 Getting the machine ready

When you’re ready to use your plasma cutter let’s make sure everything is hooked up and ready to go.

  • If your machine needs external air, then hook up the line now. If the machine compresses it’s own air, make sure the unit is hooked up to electricity, the pressure gauge is active and the air is building up.
  • Your machine will have a specific air pressure for optimal cutting, be sure to reference the manual. When you begin to cut the air pressure will drop. This is normal and to be expected. When you release the trigger and stop your cut the pressure will build back to whatever PSI you selected and the gauge will show your current PSI.
Adjustments

Now that your machine has power and the air is flowing, you’ll need to make some adjustments.

  • Check your Amperage. You’ll need to set your amps to accommodate the material you’re cutting. The rule here is of course, the thicker the material the higher the amps. Many machines will have the standard 50 amps. And those will cut everything ½” thick and less. Lower amp machines will necessarily be reduced to cutting thinner materials.
  • The Torch. Since you’re cutting with very hot compressed air most guns have two safety features built in.
    • The first being non-operation: the machine will not work if the torch is assembled and missing a piece.
    • The second safety is the trigger guard. Since the plasma cutter will cut anything that conducts electric you want to make sure you’re aligned with your workpiece and ready to go. So once you have the torch-lined up you’ll want to lift your guard then depress the trigger to cut.
Safety

We’ve just covered the current adjustment of the plasma cutter. But let’s talk about you for a second. Cutting with plasma is messy. Sparks and dross can fly everywhere. Especially if your travel speed is off. So, in order to be safe you’ll need:

  • Good eye protection. Welding requires a hood because sparks fly toward you and the light is much brighter when compared to plasma cutting. We recommend that you use shaded cutting goggles or a welding helmet with an adjustable shade.
  • A flame resistant jacket is also essential.
Operations

Ok, you have your plasma cutter machine ready and powered up. The amps are adjusted to the material your cutting and both you and the machine are safe. Let’s talk operations.

If you’re using a cutting guide you will want to have that lined up for a straight cut. If it’s a curved line, then have your magnetic guard set up.

  • Take your torch and line it up 90 degrees to your workpiece. You’ll then depress the trigger and start to move it along the workpiece. You’re actively making a cut at this point. Notice your travel speed.
  • Travel speed is important to note, and it’s easy to determine if you’re moving too fast or too slow. Here’s how :
    • Travel speed too fast: sparks and dross will fly upwards towards you, the operator. If that is happening then slow down your speed right away
    • Travel too slow: You might notice an uneven cut. If you’re moving too slow you might give the torch room to wander left or right, resulting in an uneven cut if you’re not using a guide.
    • Travel speed is just right: all the sparks and dross will be falling to the floor as you are making a through cut.
  • Finishing the cut: Strive to keep the angle the torch a true 90 degrees. This will ensure the cut is clean. If there are a few places that were not cut all the trough you’ll need to grab a hammer and give the piece a little tap so it separates completely.

Conclusion

In this article, we covered the science behind a plasma cutter, the different types of cutters available, attachments and accessories you’ll want to consider and the major uses for a plasma cutter. Plasma cutters are versatile and easy to use machines that can be used by the DIY’er and the professional alike. There are many available in today’s market, and for under $800 you can get a good MP machine, a small consumables kit and a shop compressor to get you started. If you have welding experience under your belt and you want to take on bigger and more complex projects a plasma cutter is a great investment.

For a Great How to Video from Lincoln Electric click here!