Plasma Cutter Hotter Than Sun

Is A Plasma Cutter Hotter Than The Sun? Or The Earth’s Core?

A plasma cutter flame is really, really hot. But how warm does the hottest setting on a plasma cutter actually get? Is a plasma cutter hotter than the sun? And is it hotter than the Earth’s core? That’s what we are trying to figure out here. Let’s go on a journey together, into the hottest places of our solar system. And yes, that does include the flame of a plasma cutting machine.

I want you to imagine the warmest place you can imagine. Not the Sahara desert, not at the heart of a forest fire. And no, not even on the inside of a volcano. You have to think much bigger, much warmer. You can’t cut aluminum with a chunk of condensed lava. I’m talking about a new state of matter, one beyond what we are used to. I’m talking of course about plasma, a state of matter so hot we can barely comprehend it. But how hot exactly can plasma get? What’s the temperature we are usually cutting our metals with? Let’s look and find out.

How Hot Is A Plasma Cutter Flame?

It’s seriously hot. And I’m not kidding, you don’t want to put your finger in the flame. That’s gonna scorch it right off in an instant. The heat of plasma cutters can get really intense: up to a whopping 45,000 degrees Fahrenheit! That’s about 25,000 degrees Celcius (in case you prefer that type of temperature measurement unit). It’s really intense, so never look directly into the flame. That can permanently damage your eyes.


Look at that hot flaming beast

To compare that with a regular oxyacetylene flame (used in a regular oxy-fuel welding machine): that type of cutter is ‘only’ about 9,000 degrees Fahrenheit (5000 degrees Celcius).  The reason plasma is so great for cutting is exactly the mind-boggling amount of heat it produces. You can’t place a bit of plasma on an aluminum work desk, it would go right through it. That’s why they need to create complicated floating devices to keep plasma positioned. It’s like a little mini-star inside a box, such as the image below. Don’t worry, you don’t need to do this with a plasma cutter at all. But it’s a cool thing if you wanna keep a piece of plasma super-hot at all times. Just for fun.


Plasma is hotter than your daughter for sure

Keeping plasma as plasma is pretty energy-intensive, so keep that in mind when using your cutting device. It’s gonna eat through your electricity bill faster than it’s gonna cut those chunks of metal. So if you need to use it, keep it at it’s lowest possible setting ánd make sure you turn it on and off quickly. Not just for the electricity cost, but also for the risk it might pose (don’t put it near your body, that’s gonna hurt).

Is A Plasma Cutter Hotter Than The Sun?

Yes, a plasma cutter is arguably hotter than the sun, but it depends how you look at it. Plasma cutters are certainly a lot warmer than the average surface temperature on our Sun: around 45,000 degrees Fahrenheit (25,000 ° Celcius). The average temperature on the solar surface is 9,941 degrees Fahrenheit (5505° Celcius). So by calculation, a plasma cutter flame resembles roughly 4.5 sun surfaces worth of heat.

The heat of a plasma cutting flame would be similar to some of the upper inner layers of the flaming ball of heat we call our Sun. So it’s kind of difficult to use a measurement that focuses on solar temperatures. Perhaps another hot place in our solar system would give us a better measurement reference. What about the core of the Earth, might that give us a better measurement? Let’s check it out.


Such a cute little solar flame. So much weaker than my plasma cutter.

Is A Plasma Cutter Hotter Than The Earth’s Core?

Looking a bit closer to home, the hottest naturally occurring thing we can imagine is probably the very core of our own planet. A few miles under our own feet, things can get really hot really fast. The iron core of our planet is however not liquid, so it’s not as crazy as it sounds. The iron core is solid, but still way too hot to touch for sure.

But are average plasma cutter flames actually warmer than the core of the Earth? We can definitely say yes to this question: plasma cutters are hotter than the core of the Earth by a large margin. The estimated temperature in the warmest regions under our feet is 10,800 degrees Fahrenheit (6000° Celcius).

Fun fact: We used to think it was a bit cooler down there, but measured a few years ago that it was actually about a 1000 degrees warmer. So we have to adjust our measurement there. Taking into account the original 45,000°F, we divide by the core temperature of the Earth, and now we know that a plasma cutter is about 4.17 times hotter than the center of the Earth. Wow, that’s pretty warm isn’t it! Better not stick your fingers in front of that flame.

Why Is Plasma So Hot?

Essentially, this is because of the energy contained in plasma particles. As you might or might not know, plasma is the fourth state of matter, and it can be sorted right in with the more common states of matter: liquid, solid and gas. The more energy you add to a molecule or atom, the further it moves on the scale in terms of its form of matter. That looks a little something like the following:


The more energy you add, the closer we get to the ‘plasma’ stage

The heat is produced by atoms and molecules frantically moving up and down. So when the atoms are calm, they are orderly stored alongside each other and they ‘stick’ really well together, which gives us a chunk of solid matter. Now, the more those atoms heat up, the more they start dancing and moving around like a bunch of maniacs. Moving to a liquid state, a gas state, and eventually, those atoms reach a super-hot tipping point. And that’s where the magic happens!

This tipping point is the exact moment when a regular gas (such as the stuff you breathe in right now) gets a jolt of energy that it cannot ‘dance away’ anymore by moving up and down. Electronic jolts move from the electrons to the neutron and a freaky miniature thunderstorm starts to happen. Plasma is created, a monster of nature, with powers you have never imagined possible!

Okay, I’m exaggerating here, but I like to make these things sound a bit more fun sometimes. It is true though, that the more energy is added, the more dancing and moving happens, and the tipping points actually are very interesting on a molecular level. Those are, however, not things you should worry about in the workshop. It’s just something that happens on a tiny, microscopic level. So let’s close off this thought experiment with some useful, practical advice.

Some Practical Advice

Now, I don’t want to give a full physics lecture here, so let’s get a little more practical. It’s good to know that when using your cutting machine, the plasma flame emitted is not actually always this hot. You can adjust your settings to make it more or less the intensity you prefer it to be. You will certainly not always use it at the highest setting, because of multiple reasons:

  • It’s often completely unnecessary to go to the maximum heat setting;
  • It eats up a lot of electricity, so better not use it for too long to save on that electricity bill;
  • Most materials can be cut using other methods, it is a somewhat specialized tool;
  • The protection on your machine often prevents higher settings by default as a safety measure;

But it’s really fun to learn about super-hot things, and it’s even more fun to be able to use it. If you’re interested in learning about the different types of machines out there, I do have a recommended welding equipment list for you. Next to the plasma cutter machines, you can also find a lot of protective and safety gear there, which is something you certainly are going to need when starting to use these types of tools. You absolutely don’t want to use heavy duty machinery without protection, that’s very dangerous. So keep safe out there, and keep this fun fact about the surface of the sun in the back of your mind when using your cutter next time. Stay safe when using those tools though, it can be pretty warm out there!


  1. I saw plasma cutters being sold in a hardware listing. Although I am 59, I do not recall ever hearing of such a thing. (Then again, they generally did not teach Shop to the girls.). So I googled it and WOW! What an answer! Thank you! May the force of the plasma be with you!

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