How To Stop A Fountain Pen Leaking Into Its Cap Fast!

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More and more people are making the switch over to using a fountain pen rather than a rollerball or standard ballpoint pen and with the surge in popularity, we have noticed more and more people reaching out with a number of questions about fountain pens. One of the frequently asked questions that we have noticed asked each month is based around problems with your fountain pen leaking into its cap.

Due to this being a relatively common problem for entry-level fountain pens, intermediate-level fountain pens, and premium-level fountain pens fountain pens on the market, we have decided to publish this dedicated article on the topic. We hope that we will be able to help any of our readers who are having problems with their fountain pens leaking into their cap and help you stop the leak.

Unfortunately, there are actually a number of common causes of fountain pens leaking into their caps and each unique cause needs its own unique fix. Thankfully, most of the required fixes are quick and easy to do in the comfort of your own home without you having to have any specific tools.

We have added our table of contents below to help save our readers time and let you skip to the cause you may think might be cause the ink leak in your pen. That said though, if you are not sure what the cause is, reading the whole article is probably the best option.

How To Stop Your Fountain Pen Leaking Into Its Cap

Please note that we have tried to organize the causes below in an order that should be able to help our readers and save you time. Work your way through the causes in descending order and move onto the next cause if you are confident that the first one is not the reason that your pen is leaking into its cap.

What Temperature Do You Store Your Pen At?

This one is an overlooked cause of fountain pen ink leaking into the pen cap too but this is rarely due to the actual fountain pen but the ink that you are using in it. If you are using cheaper, lower quality ink in your fountain pen then the temperature of the room can end up causing the ink to leak into the pens cap. Depending on the quality of the ink, your body heat can be enough to cause it to leak if you have your pen in your jacket pocket against your body.

Thankfully, this is one of the easiest ink leaking issues to fix as you simply switch out the ink that you are using in your pen. We usually recommend the Noodlers ink range to our readers due to it being a premium quality ink with a lower price tag than its competitors. It also offers outstanding performance while also being available in a wide range of colors too and is usually free from any temperature related issues.

Are You Storing Your Pen Correctly?

Without a doubt, the most common cause of a fountain pen leaking into its cap is due to your pen not being stored correctly when not in use. Although we have our article on how to store your pens that goes into much more detail on storing a number of different pens, you should almost always be using verticle pen storage and storing your fountain pens nib up when not in use.

If you store your fountain pens nib down then you risk your pen leaking into its cap, especially with the entry-level fountain pens but this is a quick and easy fix as you simply flip your fountain pen to being stored nib up. Although some people can get away with storing their fountain pens horizontally, this can still cause their ink to leak into their nib on occasion so can still be the cause of your problem.

Is The Nib Too Wet?

Although some fountain pen nibs are wetter than others by design, a regular wet writing nib should not routinely leak into its cap when not in use unless there is something wrong with it. The most common cause that can cause a wet nibbed fountain pen to leak is damage to the tines on the nib and a visual inspection of the nib of the pen should be able to show if this is the cause as the damage will almost always be easy to see.

Due to there being a few other reasons that can cause a wet nibbed fountain pen to leak into its cap we will just link you to our article on how to fix a fountain pen that is too wet rather than types everything out again here. A quick and easy way to check if this could be the cause of the ink leaking into the nib of your pen is to hold your fountain pen in your hand and flick your wrist to see if there is excessive ink splashing. If there is, there is a good chance that this is the cause of the fault.

If the tines on the nib of your fountain pen are misaligned then you are able to quickly and easily fix the issue at home in less than 30 seconds using the method in the video below.

Does Your Pen Have A Pull Off or Twist Off Cap?

An often overlooked cause of a fountain pen leaking into its cap is for fountain pens that use a pull off cap system rather than a twist off system. Due to the slight vacuum that the cap causes when you remove a pull off cap, it can for some ink out of the nib of the pen, especially on the more popular entry-level fountain pens and make it look like you have an ink leak when your pen is not in use.

Depending on the specific fountain pen model that you use, the vacuum created by applying the cap can be surprising and be enough to pull a large amount of ink from the nib when the cap is removed. Due to the amount of the ink being removed and the fact that it is being pulled out due to a vacuum, it can appear to be a bad leak with the nib of the pen when in reality, it is just the cap locking system making it look like that when there is no actual leak.

This one can be a little tricky to workout if the pull off cap is the cause of the issue or not but thankfully, there is a way that you are able to check. Simply clean the areas of the pen that have the leaked ink on them with a paper towel and then place your cap on it, don’t apply the pressure to actually lock the cap in place and cause the vacuum and then leave it overnight.

The next day, remove the cap and due to there being no vacuum, you should be able to tell if this was the issue as there should be no ink leaking from the nib. If the nib is clean then the issue is due to the push lock cap and unfortunately, at the lower price points for fountain pens, this can be common. If the nib does have ink leaking from it then the issue is something else.

Are You Using A Cartridge Converter Pen?

This tends to be a less common cause of modern fountain pens leaking due to modern cartridge convertors being much better than their older variants. That said though, if your fountain pen uses a cartridge convertor system rather than a piston filler, it may be the cause of the ink leaking into its cap.

There are two main issues, the more common one is that people are using third-party ink cartridges with their pen that don’t form a perfect seal with the cartridge convertor and end up causing a leak. Considering the official brands ink of the fountain pen you are using is usually only a dollar or two more, we would highly recommend that you use the official cartridges for your pen to ensure that you get that tight seal to stop any ink leaking.

The second is that the cartridge convertor itself may not be correctly mounted to the feed of your pen. Depending on the pen model that you are using this can be a bit of a pain to fault find. We feel the easiest way to tell if this could be the issue is to shake the pen and see if you can see the convertor wabbling around in the barrel of the pen or if you can hear it moving. If you can, your convertor is probably not mounted to the feed of the pen and this could be your issue.

Are You Using A Vacuum Or Piston Filler Pen?

An even rarer cause of a fountain pen leaking into its cap when not in use is due to over filler on either vacuum or piston filler fountain pens. The maximum ink capacity of fountain pens is clearly listed for a reason as overfilling can result in an overpressure that in turn can lead to ink leaking out of the nib when not in use.

The easiest way to try and workout if this is the cause of your pen leaking into your cap is to only half fill your pen and see if it keeps leaking. Unlike a cartridge convertor fountain pen, you don’t have to fill a vacuum or piston filler pen to maximum capacity with each refill so you can put a much smaller amount of ink into the pen and see if the fault persists.

Have You Had Your Pen On A Plane?

This is one of the rarest causes of a fountain pen leaking but if you have had your pen on a plane recently then the pressure changes in the cabin of the plane while in flight can end up causing the nib to leak ink. A common mis-conception is that the pressure in your pen will normalize after landing but this is not the case for a vacuum or piston filler based fountain pen and you usually have to re-fill the pen to normalize it and clear the fault to stope it leaking.

Can You See Any Damage On The Nib Or Feed Of The Pen?

Although this may seem obvious, if none of our tips above have managed to stop your fountain pen leaking into its tip then carry out a visual inspection of your pen for damage. Note that the cause of the fault may not actually be on the nib so check the section, the feed, the barrel, piston filler/vacuum filler/cartridge convertor, and barrel for damage. If you see anything that stands out then that is the only other thing that we are able to think of that may be causing your pen to leak.


That brings our article on how to stop your fountain pen from leaking into its cap to an end. We have covered all of the common and less common causes of a pen leaking as well as how to fix them. If your pen is still leaking then seeking the assistance of the nibmeister in your local stationary store is probably the best course of action as they will be able to do a full inspection of your pen and offer more specific advice for you.