3D Printer HardwareReviews

NF Crazy Hotend – A Mosqutio Hotend alternative

A few weeks ago, I tested the Mosquito Hotend and i really liked it. It offers really good performance, improved retractions and one-handed nozzle changes. Unfortunately, the thing i did not like the most is the price. I could not justify installing a $200+ hotend on the Ender 3 which is cheaper.
So, I found out about the NF Crazy Hotend from Mellow that is cheaper. After I tested it for around 50 hours of printing, here are my thoughts about it.

NF Crazy Hotend vs Mosquito Hotend

As you can see, the NF Crazy design has a lot of similarities compared to the original Mosquito Hotend, but it also has a small changes.

The heating block is a bit more square and it has a tightening screw for the heater cartridge. I like this design beter than the original Mosquito because it allows you to install the cartridge without using Boron Nitride paste. By doing that, you can easily swap the cartridge in the future.
Another difference compared to the original Mosquito is the heat break. It is not made from titanium (the material used is stainless steel) but in my testing i did not find any issues with it. The heat break is a bit hotter than the original, but the difference is not something that should be considered on normal printing temperatures.

I learned this the hard way, because due to my lack of attention, the heat break cooling fan was not connected properly and i experienced a clog. When i installed it, i used the same Boron Nitride paste i used on the original Mosquito and this made my task harder. So, i recommend you install the heater cartridge normally, and properly tighten the screw.

In the original package, you get the NF Crazy with a metal groove mount adapter and a high-quality plated copper V6 nozzle. Another thing i like is the availability of NF Crazy parts that can be ordered separately. You can order the heat break replacement or the copper heating block if yours get damaged or you cannot properly clean them. I asked Mellow about the availability of a silicon sock for this, and they confirmed that they will have it in the future (early December). I will order one as soon as they become available because they improve insulation for the hotend and they keep i clean.

Mount for the NF Crazy / Mosquito Hotend

BLV mgn cube - Mosquito + BLtouch

I installed the NF Crazy on the BLV MGN Cube using the dual-fan mount adapter from Thingiverse made by shadewind.

Test prints

Here are some prints I did using the NF Crazy Hotend with the BLV MGN Cube. Please be advised that the hotend will not always dictate the quality of a print. But on a well tuned printer, things can be improved.

NF Crazy Hotend Review
NF Crazy Hotend - A Mosqutio Hotend alternative 1

This is the first print I did, with the same settings used with the E3D V6 hotend – Devil Design PLA – 0.15mm layer height, 60mm/s print speed and 215c. The temperature was a bit too high and that caused bad overhangs on the “X”.
And because this is the Magnum NF Crazy (which is similar with a E3D Volcano in comparison) lower temperature is needed.

NF Crazy Hotend Review

In the pictures below, I printed a Raspberry Pi 3 case in Devil Design PLA – 0.15mm layer height, 80mm/s print speed and 205c.

The results are really good. The parts were finished in less than 3 hours and as you can see there’s no stringing.
I also printed a Duet 2 WiFi case in Devil Design PETG – 0.2mm layer height, 70mm/s print speed and 230c


The NF Crazy Hotend is a really good hotend that takes most of the really good features introduced by the Mosquito Hotend from Slice Engineering and offers them at a lower price.
If you plan to use this hotend for printing high temperature materials (over 300c) it will probably not work as well as the original. But for regular users that want a really good hotend, with excelent cooling and single-handed nozzle swap, the NF Crazy is a winner.
At the same time, i applaud the design of the Original Mosquito Hotend and if you can afford it, i recommend you buy theirs to support their effort in offering a new alternative in the 3D printing space.

As a sneak peak of information – A dual color NF Crazy hotend will be available soon and i can’t wait to try it out. This is another piece of evidence that similar alternatives appear in the market and an original design can be further improved by others.

Where to buy?

The NF Crazy can be bought from Aliexpress.

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2 months ago

Is it possible to use mosquito heatbreak on NF Crazy Block and heatsink ?

3 months ago

I installed the NF Crazy with a Hero Me on my Ender 3 but it’s not working so good for me 🙁
I would say it prints fine for the most part, a bit more stringy than the stock cause i had to lower retraction a lot not to get clogs, but the problem is each time i change filament it clogs and i need to take the ptfe tube out to push the remaining filament down the nozzle.
I’ll probably go back to the stock cause i can’t think of any solution.

wen clone
wen clone
4 months ago

where can i find tihs hot end? slice engineering have patent trolled all these sellers. looking for a new source to purchase, don’t want to support that company.

Michael Meech
Michael Meech
1 year ago

Did you change any thing in Marlin for the Crazy?
I am installing one on my X1 and having some issues with the high temp thermistor, I have now swapped back to the original which is working, but the filament loads ok but then sticks I think its swelling maybe while in the cool end.

5 months ago
Reply to  Michael Meech

you get this figured out? I’m considering getting one for my X1 as well and I’m a little cautious about the quality of the Crazy hotend. I’m torn between this and the Dragon.

Gordon Atwell
Gordon Atwell
1 year ago

Any chance of swapping out the stainless steel tube for a titanium one?

1 year ago

Hey, that’s a great review. I’m interested in getting the nf crazy or the dragon plus direct extrusion combo installed on my cr10s pro. Much like you had it on the dragon review. As I am much more on the beginner side than you are I am not sure though if and what kind of firmware modifications I’d have to make to get it working. Would you mind sharing your configuration? Cheers

1 year ago

Hi, finaly did you test the dual color NF Crazy hotend ?
I’ll wait to received mine and also a Sapphire plus, if you have any idea to do best adaptator for fit this dual crazy on Sapphire plus?