How to Use a Plasma Cutter





Introduction: How to Use a Plasma Cutter

Using a plasma cutter is very convenient and fairly easy.  The benefit is that "freeform" cuts can be made to metal based on guiding the cutter.  Since this machine works by directing plasma through the creation of a circuit, a ground clamp is necessary, much like welding. 

This instructable is strictly to show practical operation of a plasma cutter.  For an example where this operation is demonstrated to make something, refer to Sheet Metal Flower to Practice Plasma Cutting and Welding.

I made this at TechShop Detroit (

Step 1: Choose Work Location

Since we plan on cutting metal, placing the metal on a surface that is safe and allows for freedom of movement is critical.  A "grate" or  similar surface that functions as a table is perfect.

Step 2: Plug in Unit

Ensure that the unit is off and plug it in. 

Step 3: Connect the Air

Connect the external air compressor to the plasma cutter.  This is to ensure that the stream of plasma remains under high pressure. To attach the fittings, recede the outer flange of the female connection and insert the male connection.

Step 4: Turn the Air On

Turn on the air flow.  In this case, turn the lever ninety degrees from perpendicular to the air line to inline.

Step 5: Attach the Ground Clamp

Set the metal that you are using on the table and attach the ground clamp close to where you will be cutting.

Step 6: Turn on the Machine

Turn on the machine by flipping the switch behind the unit into the ON position.

Step 7: Set the Current

In this case we will set it to 25 for 18 ga sheet metal.

Step 8: Cut the Metal

Use the trigger on the gun to activate the plasma cutter.  Note the trigger has a safety that must be lifted before you can depress the trigger.  Keep the cutter (nozzle end) close to the metal and use the guide surrounding the nozzle to trace templates if you have them.

Step 9: Turn Off the Machine

When you are finished cutting your metal, turn off the machine.

Step 10: Disconnect the Ground Clamp

Disconnect the ground clamp from the metal you are working on.

Step 11: Turn Off Air

In this case turn off the air by rotating the lever 90 degrees, from inline to perpendicular to the line.

Step 12: Wind Up All Hoses

Wrap up the plasma gun line, air line, and ground line.



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    Skip the air, use propane and oxygen while cutting, much more fun, hehehehehe. (For the nubs, this was a joke)

    I was expecting some technique, rather than just "plug it in and turn it on"

    1 reply

    So I did...

    The air has to be as dry as possible, dryers in the line are a necessity. The water in the driers should be bled off before turning on the air.

    2 replies

    this is SOOO cool., I can't wait to get one=!!

    To turn on the air valve, turn the handle from perpendicular to inline.

    1 reply

    Fixed, thanks for your feedback.

    Could you have mixed up the photos showing "air on" and "air off"?

    3 replies

    most likely, never seen a ball valve on, at a right angle

    I did. Thanks for pointing it out, I appreciate the feedback.

    I just need to double check you on this. I have never seen a valve of that type that is OPEN when the lever is perpendicular to the pipe.

    1 reply

    Thanks for double-checking. I have edited the instructable and appreciate your feedback.

    It is not the posters fault that they chose her Instructable for the newsletter. Give her some credit I understand she did not provide much, but for some people this actually does help them. I know its not much, but this is also her 4th able and maybe she is going to continue posting as she learns more. Maybe she just started cutting and this was new to her. As for the air she does need to edit that it is a dangerous confusion. We are a friendly community please comment with constructive critiques rather than bashing that she did not give enough.

    Well that wasn't very informative at all.... go back and try it again

    I learned the hard way that cuts should begin from an edge on the metal, not from the middle of the surface. Also, could you say something about how far to hold the gun above the surface and how to know if travel is too fast or too slow? Thanks.

    2 replies

    With practice, I have found that cuts can be started quite predictably by piercing the metal at a shallow angle first - maybe about 50 degrees or so - and then 'rolling' your wrist and the torch jet to the regular cutting position and continuing as normal from there. Spatter can spray back at you (and has for me in a few cases) if you try and pierce metal holding the torch perpendicular to the surface. However I still drill a small hole for starting the cut on thicker pieces just in case.

    Good point! I addressed them in my recent "Sheet Metal Flower to Practice Plasma Cutting and Welding" one.