Monday, December 21, 2015

J-Head Mk 8 and Mk 9 hot-ends

Lately, I have been asked if I will be making more J-Head Mk 8 hot-ends. In addition, I have developed a proper J-Head bowden hot-end that is based off of the J-Head Mk 8 and have named it the J-Head Mk 9.

However, I will not be producing nor selling more of the J-Head Mk 8's and Mk 9's because of what has happened to the J-Head hot-end.

The chinese made a poor, rough, copy of a J-Head and spammed it all over the online markets. People bought the cheap knock-offs and those hot-ends failed. The result was that all J-Head hot-ends got blamed for this failure even though the cheap chinese knock-offs were (and are) very different from the real J-Head hot-end. Most of these people now buy other hot-end designs.

The closest open-source analogy that I can think of is this example: Imagine if somebody took FreeBSD, introduced a couple hundred bugs, then released it as a new Linux distribution. Because of this, people begin to dislike Linux. In my opinion, this is what happened to the J-Head hot-ends. (Please note that this is not meant to say anything negative about FreeBSD, it is just an example.)

The concept of open-source design is to take a product and improve it then release the source code or blueprints. It is not to take a product, break it, then not release any information.

Because of this, I have stopped all research and development work towards better J-Head hot-ends. I absolutely refuse to create new designs given what has already happened. I have also noticed that a lot of Reprap-related R&D has stopped in other areas as well. This makes me wonder if the other developers have left due to similar reasons.

I would also like to add that you get what you pay for. Quality products and new research and development cost money and a company that sells both will have to charge a higher price. A cheap, poorly made, knock-off will be cheap in both price and in quality.

I am still selling the J-Head Mk V-BV hot-ends at


  1. Could you do something like stamp a makers mark into the official J-heads? or maybe start a new line of non open source hot-ends, would not stop them from copying but might give you some leverage to force them to at the least call them something else.anyway had to give my (unsolicited) 2 cents have been using your hotends since i got my as then newist reprap the pre-prusa, Mendel.thank you for continuing to sell the J-Head Mk V-BV hope for updates but do whats right for you.

  2. Hello,

    I haven't made up a makers mark as it would add an additional cost. People have been buying by price alone and it's very hard to find real J-Head hot-ends in the sea of fakes. My guess is that when people see the price of a real J-head, they just buy the fakes. But, it's a guess as I don't really know what they are thinking.

    I'll keep making them for now and may release the J-head Mk 8 officially at some point.

    Best Regards,


  3. Speaking as a member of Thames Valley RepRap User Group, we have produced many kits of 3D printers using your j head Brian. I have been demonstrating 3D printing and consulting, and while other printers have come and gone, the combination of our very rigorously selected components including your j head has never once let me down. That is, zero clogs in 4 yearPlease, keep doing what you are doing.

  4. Very sorry to hear this -- Other than buying the better quality heads from people like you, is there anything we can do to encourage that you at least produce some batches of Mk 8 and Mk 9? I've been out of 3D printing for a year or two, and it's very bittersweet to see 'oh yeah, the print head has improved, but it's not available'. I became tremendously happy back in 2012 after replacing a crappy head/setup with your Mk V..

    1. to clarify - The Mk V was purchased from ..

  5. Brian,
    I understand your disappointment.
    I have been gathering parts for over 3 years. Bought one of your MkV from you after a lot of research on the forums. It became obvious that to get a reasonable print, I would require a good hotend, and not the general rubbish available which includes clones. Note I haven't built my Prusa I2 yet, but at least I have bought parts from people who care and have givenback to the reprap project.
    I do hope you recover from this setback. Just know that those of us that want a decent printer are willing to pay for the work that goes into producing an excellent product.