Plasma Cutting Basics

Today with advancement in technology, Machine costs have become lower and their sizes smaller, compact and even portable. A great advancement in that path is the plasma cutter; the market is flooded with so many plasma cutters that you can use them right at your home, for any occasional repair and maintenance work easily.

What is a plasma cutter?


Plasma cutters are similar to electric welders, instead of joining they separate metals of varying thickness and electrically conducive materials. It uses a process of using high velocity jet of ionized gas which is delivered through a constricting orifice.

This high velocity gas or plasma conducts electricity from the torch of the plasma cutter to the metal and cuts it precisely by heating and melting the material.

As it does not require a pre heat cycle it is widely popular among smaller shops today and add to it the ease of use, higher quality of cuts as well as quicker travel speeds, one would not hesitate to buy the basic model for in-house purposes.

Basics of Plasma Cutting:

The method of cutting with plasma cutters is easy to learn. Even a novice can cut easily with just a few simple steps of knowing the fundamentals.

Let’s look at the basics for every beginner to make a quality cut using plasma cutters.

1. Thickness of the metal:

Plasma cutter can cut a wide range of metals which are electrically conducive like steel and copper. But the ideal thickness of the metal should be 1 inch or less than an inch to get the best quality cut.​

2. Amperage of the plasma cutter:

Most residential use models have an amperage setting of 40 amps to 100 amps.

The amps indicate the maximum thickness the plasma cutter can cut.

The amp also indicated the amount of power volts required for the machine. Usually 40 amps to 100 amps plasma cutters can be used for residential purposes as the normal voltage supply available would be 220V which is enough for this amperage.

The thickness of the metal in this case would be less than 1 inch.

When you use the very basic model from Longetivity – the maximum amperage allowed in the cutter is 40 amps and the maximum it can cut is 3/8” of metal thickness.​

3. Set your machine properly:

Air pressure settings:

How much air pressure you use is very important in the plasma operation.

More air can blow out the plasma, while less air cannot cut anything making the torch to meltthe metal into a mess.

All models will provide a guideline to set the air pressure, make sure you follow and set the air pressure right if you don’t have an automated model.

The normal air pressure settings for a good cut can be set around 60 psi when you are using it for residential purposes.

Voltage settings:

Set the right voltage you need for your plasma cutter.

This depends on the thickness of the metal to be cut.

Because, when you always use the highest settings, you will end up with erratic cuts with a lot of swags on thinner metals. When using aluminium use lesser voltage as compared to using it in Steel.

You will get these guidelines on the proper use of voltage by referring to your machine’s range.

Safety measures:

With the right air pressure and voltage you are good to start cutting up your metal. But, before than you need to take some safety precautions and use safety gear.

Get some heavy welding gloves and a coat or sleeves to protect your skin from the high levels of heat, electricity and light. Also get some gas torch goggles with a minimum #10 shades to protect your eyes from the light and sparks.

Another gear required in your safety list is the automatic welding helmet which has adjustable settings, so as to not to obscure your visibility while working.

Cutting techniques:

The right way to cut the metal is to drag your plasma torch along the metal.

Hold the plasma torch at least ¼” away from the metal and move in the direction you want to cut.

For thinner metals, a straight angle usually works as they get easily penetrated and cut, but if you want to cut thicker metals you need to hold the torch at a 45° angle so that the molten material is blown away from you and the cut.

Thinner material also requires faster travel speed whereas thicker material will require a slower process and more piercing time.

The right travel speed is very essential in your cutting technique, when you see that the torch has not properly pierced and cut the metal then you may be doing it very fast, or if you blow out the metal you might be doing it slow.

Also, not just sheets can be cut with plasma, but complex shapes of metals can also be cut. For that, you need to study the shape you are going to cut.

You will have to choose the right base of the complex shape that needs to be cut first. Usually the way to go is to choose the thicker and larger base and cut them, before proceeding to the lesser base.

Always hold your torch at 45° angle for best results.

Once the cut has been done in the metal, you will find some slag on both sides of the cut. This can easily be chipped off using a chisel or a hammer.

When thicker metals produce more slag which is difficult to remove, you may have to resort to the use of a grinder.

Once you have mastered these basics of plasma cutting, you might be on the lookout to try out new things with your plasma cutter.

It is very interesting as well as a lot of fun.

All you need is a little practice and precision. Start your practice with scrap materials and proceed to your actual ones that need to be cut.

You will go a long way with this great handy tool called plasma cutter in your home and sort out all your operating and maintenance work by yourself.

  • April 3, 2017
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