What is the difference between the two flex nibs?

Pro-Flex - Pros:

  • Juiciness - It's fitted with professional calligraphy nib (the Zebra G) giving you the greatest variance between thick and thin strokes, from hairline up to 2mm.

  • Softer - it's a doddle to flex, requiring very little pressure.

  • Ink Flow - The Japanese ebonite (a special type of vulcanised rubber)  feed delivers just the right amount of ink.


  • Replacing - because a calligraphy nib's raison d'être is to flex, they're made from alloys which are beautifully soft but can corrode and wear. So, just like a calligraphy pen you'll occasionally need to replace your nib when you notice any  (available on my site).

  • Heat Setting - One of the tricks to getting the most from any flex nib is good contact between the feed and the nib. One of the clever things about ebonite is that it becomes malleable with heat, meaning you can achieve a super cosy fit for optimum ink flow. This process is called heat setting and I do it to every nib, but it can occasionally need re-doing if the pen is knocked etc. I'll be making a video to demonstrate this but a quick google will also give you a good number of explanations and videos demonstrating the process. If you're not confident about this I would recommend the Semi - Flex nib instead.

  • Snag - The hairline nib when un-flexed creates beautifully fine strokes but if you're new to calligraphy or using a nib like this you will notice that it will snag on paper simply because it is so fine.

Semi-Flex - Pros:

  • Maintenance Free - If you're not a calligraphy or fountain pen nerd and want a simple maintenance free writing experience, the Semi-Flex is the way to go.
  • Durability - It's essentially a fountain pen nib (gold plated stainless steel) that has been designed to be make it more flexible so it will be more durable than the pro-flex.

  • Smoothness - The Semi-Flex is an extra fine tipped fountain pen nib, which means that nib has an Iridium (super hard metal) end where it meets the paper.  Increasing durability of the nib and making it smoother to write with on a variety of paper types.  


  • Flex - Not really a con as it's still more flexible than 95% of the fountain pens out there but compared to the Pro-Flex it's not as soft and more effort is required to achieve a thicker stroke. 

  • Hairlines - The pen is tipped which as I mentioned before increases durability and smoothness but this means it can't achieve such fine hairline strokes as the Pro-Flex.

  • Ink Flow - Flex nibs are inherently thirsty pens and require the feed to keep up and deliver ink to the nib so that it doesn't run out mid-sentence.  The Pro-Flex ebonite feed is the best in the world at delivering ink and is the main reason for the price difference between the two.  The Semi-Flex has a plastic feed which is good but due to lots of incredibly geeky factors can on occasion run out after lots of juicy inky flexing. It's easy to get it flowing again (by pushing more ink in using the included ink convertor) but it's worth considering before purchasing.


Can I keep ink in the pen between uses?

  • By all means, all of the gold plated fountain pen nibs will not corrode. The Pro-Flex will corrode eventually but you can easily replace it, or prolong it's life by flushing your pen with distilled water after every use and drying it.


What's the difference between the Sumi and the Spark?

  • Unlike the Sumi which is predominantly a desk pen, the Spark is designed so that you can take it anywhere easily.  It uses a new larger nib size which is better suited to flex nibs and makes it compatible with the Zebra G nib.  The spark also keeps all of the lovely weight of it's brass parts but they are all gold plated so they won't tarnish.


What inks can I use in the Spark? 

  • The Spark pen works beautifully with all fountain pen inks, I recommend Diamine Inks (including shimmer!) You can find them here).  Be sure not to use calligraphy specific ink as this can clog the pen.

Good to know:

  • We recommend you flush your Spark pen thoroughly before use. This will remove any oils from the nib which are present during manufacture, and will impede ink flow. Any of the following are good options: our Nib Cleaning Solution, distilled water or water with a touch of dish soap.

  • Every pen is machined from solid metals on a lathe used for making fine watch and aerospace grade components, so you can be sure your pen will write perfectly for years and years to come.

  • Every Pen is dip dyed by hand so may have small speckles or colour variations; it's part of what makes your pen unique!

  • We offer a complimentary repair service, so should your Spark pen needs a little TLC please contact us.