Rotring Isograph vs Rapidograph

The main difference between the Rotring Isograph and Rapidograph comes down to the refilling mechanism.

Body design of the two pens are quite similar. They are both plastic body pens with the exception of the metal clip and pen tip. Both are technical pens that create strokes with uniform width. Both are available with line widths from 0.1 to 1.0.

The green pen at the bottom is the Rapidograph. Rotring is not the only company that makes the Rapidograph pen, the other is Koh-I-Noor. I'm not sure if the Rapidographs from Koh-I-Noor are similar to Rotring's though.

Performance of both Rapidograph and Isograph are the same. Ink flow is the same too.

The Isograph can be dismantled completely and easily. With the Rapidograph, I was not able to dismantle the air channel (the one fused to the tip) to remove the pin that's inside. So cleaning the Rapidograph may take longer time.

If you have problem removing the Rapidograph air channel, you can screw it to the back of the pen's body and pull it out gently. It's likely to get stuck because of ink or dried ink. But be careful not screw it so tight that you can't remove it later.

Rapidograph is meant to be used with disposable ink cartridges while the Isograph has a cartridge that can be easily refilled.

If you refill the Rapidograph's ink cartridge by inserting the Rotring ink bottle's funnel, the ink is going to block the opening. If the ink cartridge opening is blocked, no air can come out and no ink can go in.

Hence the better way to refill the Rapidograph is with a blunt needle and syringe. It's more economical to refill with your own ink than having to buy disposable ink cartridges.

The Isograph ink cartridge has a larger opening and you can easily squeeze ink into it with the Rotring ink bottle.

Overall, the Isograph is easier to maintain and refill. If you're looking for a refillable technical pen, I would recommend the Isograph over Rapidograph.

You can buy the pens individually or in sets. If you're buying individually, I suggest getting a few line weights, the more popular ones being 0.3, 0.5 and 0.7. If you need more variety then 0.1 and 1.0. The thinner the line, the more maintenance is required. If the ink dries in the small pen tip, it is going to clog and be very difficult to unclog.

Regular maintenance should see these pens last for years. So while each pen is expensive, they are still economical in the long run, especially when compare them to disposable technical pens.


Rotring Isograph | | | | | | |

Rotring Rapidograph | | | | | | |

Koh-I-Noor Rapidograph | | | | | | |

Blunt needle and syringe | | | | | | |

Rotring ink | | | | | | |



Hi Teoh,

Hi Teoh,

Thank you for your service(s) to the greater community. From the looks of things, I have a feeling you are sharing your knowledge and expertise internationally. I'd like to be doing that someday.

I have only begun to explore your site and I find value everywhere I look.
But, I did find a glitch and wanted to let you know. I have been an Amazon affiliate for a minute about 5 years ago. (minimal set-up knowledge). I think your affiliate link(s) may be busted. It also occurs to me that it may have something to do with different formatting from one country to another or one operating system to another. I don't have a handle on HTML and I feel as though I don't know the lingo.

Bottom line, when I click your link to look at the blunt needle and syringe I went to Amazon, but what loaded was only slightly comprehensive. It recognized me, (my computer, and I'm a frequent flyer @ Amazon), and I would be concerned that your link works properly so you get your due. Trying to navigate the messed up page would be a hassle and turn off.

Thanks again. You may hear more from me.
I look forward to any reply.

Oh, where do you hail from?

All the best!

Back when I bought a Rotring

Back when I bought a Rotring pen (15 years ago), I didn't know about isographs, because here everyone calls technical pens "Rapido". Maybe because it's easier to pronounce.

I bought 4 Rapidographs, and in my country they are rare and very expensive. There wasn't much e-commerce back then, so I had to buy used ones for $15-20 each.

I only realized that I bought the wrong type when I bought the Staedler brand. My Staedler pen is like an isograph, we can disassemble everything down to the tiny needle inside.

This type of pen is much better, to unclog it only takes 10 minutes. While the Rapidograph type, even though it has been soaked in water for several days, is difficult to clean the hardened ink inside the nib.

And we can't check it unless we put ink in it. If it is still clogged, we have to wash it again, and shake the nib continuously. Very tedious.

Honestly I kinda regret buying Rapidograph, better buy Isograph.

Btw, I have a question. Does Rotring ink have an expiration date? I still have one and a half bottles bought 15 years ago.



I have a .10 rapidograph which is clogged for several months. I tried to put it in the water for several hours and I can now hear the little bill when I shake it. I changed the cartridge and shook it like crazy but it still does work...

1/ Do you think I should try again using the rotring cleaning fluid ?

2/ If it doesn't work, do you know if one is easier to unclog than the other between isograph and rapidograph ?

Thank you

It's worth noting that water

It's worth noting that water alone isn't the best way to clean a technical pen. Commercially prepared cleaning solutions are available under Rotring and Koh-i-Noor brands. Clogged pens are best cleared by using the solution in an ultrasonic cleaner, such as jewelers use. Most tech pen inks are comprised of burnt carbon, water, and glue.

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