Why Do Pens Explode? – 5 Common Causes

Written by Laura Walker / Fact checked by Leilani Carroll

Why Do Pens Explode

Your pen exploded? Have you ever experienced the frustration of reaching for a pen, only to find an unexpected explosion of ink waiting to stain your hands and belongings? Why do pens explode?


The primary factors leading to pen explosions encompass air pressure alterations during flights, ink leakage in pockets, shifts in temperature, mechanical jolts, and defects in manufacturing.

Read on to know if we can prevent it from happening.

5 Common Causes of Pen Ink Explosions


There are no completely no-leak pens, as many factors can lead to an exploding disaster if we are not careful when handling them.

Let’s discover each cause now!

1. Air Pressure Changes on Planes


Air pressure changes are blamed for causing pen explosions, especially during air travel.

The difference in atmospheric pressure inside and outside the pen’s ink cartridge can expand the trapped air within the cartridge, potentially resulting in an ink explosion.

Therefore, if you bring your collection to a place with high altitude, your fountain pens can make a mess. Besides, it might not even write well due to the pressure.

2. Pen Leaking In Pockets


The situation becomes all too familiar when a pen leaks into your pocket, leaving behind an inky mess.

This can occur if the pen’s cap is not securely fastened, allowing pen ink to leaking into the cap. Movement or pressure changes can force the ink out, creating an unpleasant surprise.

3. Temperature Fluctuations


Extreme temperatures can significantly impact the viscosity of ink. High temperatures can cause the ink to expand, while low temperatures can make it contract.

Both conditions might cause pressure imbalances within the ink cartridge, potentially resulting in an ink explosion.

In fact, many people try to repair dried or stuck ink by heating the tip; as the temperature rises, the ink will seep out of the tip.

4. Mechanical Impact


Accidentally dropping a pen or subjecting it to rough handling can agitate the ink inside the cartridge. This agitation can build up pressure within the cartridge and potentially cause an explosion, sending ink flying.

There are no pens that don’t explode since incidents like this might happen, so we need to be careful.

5. Manufacturing Defects


In some cases, poorly sealed ink cartridges or manufacturing defects can increase the risk of pen explosions. Insufficiently sealed cartridges may allow air to enter, leading to pressure imbalances.

What Pens Are More Likely to Explode?


Because of their mechanism, ballpoint pens, rollerball pens, and fountain pens are more likely to leak ink.

The ink flow is controlled by the tiny ball at the pen’s tip. Under normal circumstances, the ball holds the ink in check.

However, the pens are more likely to leak if the ink becomes too liquid or is exposed to high temperatures, such as body heat.

What Pens Do Not Likely Explode?


Pens less likely to experience ink explosions are gel pens. These pens have been designed to resist leaking and exploding, even when subjected to body heat.

Gel pens are also less prone to leaks due to their thicker ink, which resists liquefying quickly in high temperatures.

5 Preventive Measures For Keeping Pens Safe


  • Always ensure that you securely fasten your pen cap after use.
  • Cases can shield pens from pressure changes and mechanical impacts, safeguarding them from potential explosions.
  • Storing pens with the tips upright can help minimize the pressure differential between the inside and outside of the ink cartridge, prevent excessive pressure buildup, and reduce the chances of an explosion.
  • Keep your pens away from direct sunlight, heat sources, and extreme cold to maintain stable ink viscosity and prevent pressure imbalances.
  • Choose leak-proof pens, as well-constructed pens with properly sealed cartridges are less likely to experience ink explosions.


Why do pens explode? While the phenomenon of pen explosions might appear trivial, understanding the underlying causes and taking preventive measures can save you from messy situations.

You can reduce the risk of ink explosions by securely capping your pens, using protective cases, storing them upright, and being conscious of temperature changes.

Ultimately, these efforts will ensure your writing experience remains smooth, hassle-free, and devoid of unexpected ink mishaps!

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