Are Sharpies Flammable?

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The humble Sharpie is a key feature in nearly everyone’s formative years and many of us still have our desk drawers full of them. They write very well, and they are cost-effective and attractive. Plus, they are a brand that many of us have fond memories of. But would we be as happy if we were to learn that the sharpie was a fire hazard? Let’s take a closer look.

Sharpies can be flammable due to alcohol in the ink. The plastic can also burn, but it does not catch fire easily.

Also read: What Makes Something Flammable?

What Is A Sharpie?

sharpie markers

Sharpie, technically speaking, is not a product. It’s a brand. 

That means it can apply to a wide range of pens, including gel pens, marker pens, and even rollerball pens and it’s important to note that, in general, when we are talking about sharpies, we tend to mean the marker pens.

However, when it comes to the flammability of sharpies and their ink, the same information is, broadly speaking, true across the range. There may be minor differences in the exact temperature at which a sharpie melts or ignites but there’s nothing significant in it.

Sharpies are not flammable. The plastic casing is, of course, combustible. If you heat anything up for long enough and for a sufficient amount of time, it’s likely to burn. The plastic would most likely melt and deform long before it caught fire, however, and that ought to give any user enough time to put the sharpie down and move it out of danger.

The ink used in a Sharpie is not, usually, flammable either with a very high water content which means it’s most likely to extinguish any flames that it comes into contact with. 

And, in fact, as far as we can tell – Sharpie markers come with no specific health or safety warnings (whatever Amazon customer care may have to say on the subject) and they are certified by medical experts not to contain any materials in sufficient quantity to risk anyone’s health or wellbeing.

This doesn’t mean, for the sake of clarity, that you can’t be irritated by or allergic to Sharpie ink, but it does mean you can use them with relative confidence. 

You shouldn’t write on your skin but there’s no evidence that this is a dangerous practice. 

Are They Flammable or Heat Resistant?

Sharpies can be flammable.

You can see here the ink will burn:

Why are Sharpies so flammable?

Though we do have some evidence that Amazon customer care is telling people that it is flammable, it’s can vary by definition. 

To some extent, a Sharpie’s plastic will be heat-resistant because plastics are reasonable thermal insulators, though we wouldn’t advise using Sharpies as any form of formal insulation.

It is worth noting that because Sharpies are full of ink, ink expands when it is heated, and a Sharpie can leak ink all over the place long before the plastic becomes damaged.

In fact, it doesn’t take a huge amount of heat for ink leaks to happen, particularly with a rollerball Sharpie as anyone who has been foolish enough to keep one in a trouser or pants pocket can attest to. 

So, our advice is to try and keep Sharpies away from heat because you may ruin the ink supply but you shouldn’t panic too much if they get warm, they may leak but they are unlikely to burst into flame and cause you any kind of lasting damage. 

Are They Flammable When Dry?

No, when the sharpie ink is dry, the water content may have evaporated, but there’s not enough left behind to be flammable. 

Even if Sharpie releases an alcohol-based marker, and we don’t believe that they have any plans to do so, the alcohol would have evaporated by the time the ink dried too.

However, it’s important to note that dry ink can be combustible and if you get the ink hot enough, it will burn. 

But we wouldn’t expect to encounter such temperatures in the day-to-day use of a Sharpie.

Is The Ink Flammable On Light Bulbs/LEDs?

Maybe. Sharpie themselves makes an Industrial Sharpie they say that the permanent ink from this particular Sharpie is highly heat-resistant. 

So, we think if we were going to write all over a lightbulb, given that lightbulbs can get very hot, we’d probably opt for the Industrial Sharpie.

However, we have no evidence that ordinary Sharpie ink would catch fire, either. 

One thing that we can be certain about is that under normal circumstances LED lighting generates very little heat and the LED light is unlikely to be much warmer than room temperature.

This means that Sharpie ink is not going to be flammable on LED lighting. 

Is There Alcohol In Sharpies?

Yes, Sharpies’ ink contains a few types of alcohol.

Ink ingredients:

  • Dyes.
  • Propyl alcohol (N-Propanol), 200-250 PPM.
  • Butyl alcohol (N-Butanol), 50-100 PPM.
  • Diacetone alcohol (4-Hydroxy-4-Methyl-2-Pentanone), 50 PPM.

It’s worth noting that pens that use ink that is based on Isopropyl Alcohol are highly flammable and so is the Isopropyl Alcohol wash. They should be stored with the intent of keeping them in a cool, dry, well-ventilated space and in closed containers.

Whereas your Sharpies will be fine in your desk drawer or in your bag, assuming it doesn’t get too warm and the ink leaks. 

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