Slice Engineering

Slice Engineering Prusa i3 Upgrade Kit (MK2.5/3/3S/3S+)

Slice Engineering Prusa i3 Upgrade Kit (MK2.5/3/3S/3S+)

Regular price $ 199.99 USD
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Unlocking the full potential of your Prusa i3 printer has never been easier with the help of the Prusa i3 Upgrade Kit. Compatible with MK2.5, MK3, MK3S, and MK3S+, the Prusa i3 Upgrade Kit fits a wide range of Prusa i3 models. This kit is designed to be an easy plug-and-play upgrade resulting in less downtime, less wasted filament on failed prints, less tinkering, increased throughput, and higher print resolution.

The Prusa i3 Upgrade Kit currently comes in two versions: Copperhead® and Mosquito®. The Copperhead® version utilizes the stock heatsink on your Prusa i3 and is a direct replacement for the stock hot block and heat break. Both upgrade kits utilize the stock heater and temperature sensor. The Mosquito® version contains a 3D printed enclosure which allows the easy installation of our signature Mosquito® Hotend onto your Prusa i3. Currently, the Mosquito version is only compatible with the MK3S+. We do provide links to printable parts below that can be used to upgrade the MK3S printer with the Mosquito Kit.

The Mosquito® Hotend features our patented ‘roll cage’ design that connects the heat sink to the hot block with surgical tubes. This unique construction permits the use of a very thin Bimetallic Heat Break™ that eliminates heat creep, reduces clogging, and improves printing resolution. The Mosquito® Hotend conducts 85% less heat than a standard threaded heat break and has increased structural rigidity, allowing for a One-handed Nozzle Change™.

The Mosquito® version of the Prusa i3 Upgrade Kit comes with printed parts to make the installation process as simple as possible. These parts are printed with black ASA (ASA is used for its high heat deflection temperature), but files are available to print your own parts in whatever color or material you prefer.

Mosquito® Kit includes:

Mosquito® Hotend
BridgeMaster® Nozzle - 0.4 mm
Mosquito® Silicone Boot
3D Printed Mounting Enclosure (Black ASA)
Capricorn Premium PTFE Tube (Pre-Cut)
Boron Nitride Thermal Paste
Dowel pin (For filling in the extra space in the thermistor slot on the hot block)
Hotend Wrench Set
Compatible with:

Prusa MK3S+

To use this kit on an MK3S printer, your printer must have the red PCB IR-Sensor (the black PCB IR-Sensor may not function properly with this kit) and you will need to print the following parts:

Note: Installation instructions for upgrading your Prusa i3 MK3S+ with this Mosquito kit can be found here.




The Copperhead® version of the Prusa i3 Upgrade Kit is a drop-in replacement for the stock hot block and heat break that utilizes the existing i3 heat sink. This kit allows you to reap the benefits of our Bimetallic Heat Break™ technology and copper hot blocks without having to change the entire print head.

Copperhead® Kit includes:

Copperhead® Hot Block
Copperhead® Heat Break - RepRap 1.75
BridgeMaster® Nozzle - 0.4 mm
Copperhead® Silicone Boot
Boron Nitride Thermal Paste
Dowel pin (For filling in the extra space in the thermistor slot on the hot block)
Compatible with:

Prusa MK2.5
Prusa MK3
Prusa MK3S
Prusa MK3S+
Note: Installation instructions for upgrading your Prusa i3 (MK2.5/3/3S/3S+) with this Copperhead kit can be found here.

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Bob S.
United States United States

Fantastic Hot End - but you may need to get creative with your part cooling.

I bought this hot end from Printed Solid along with their Bondtech BMG-M extruder and X-Carriage. All told, this upgrade cost me about as much as whole Ender 3, so I was wary and had very high expectations. As this was my first ever hot end and extruder swap, I had a steep learning curve, but Dustin from Printed Solid support was an amazing help and I was able to get up and running relatively quickly thanks to him. The heat block is a bit funky in design, but the end result of that super short, incredibly effective heat break makes it well worth it. The issue comes in part cooling. The BMG-M basically uses the same part cooling fan as the BMG-V6 - the problem is that the Mosquito and V6 are oriented differently. The mosquito is off-center with a majority of the block on one side. Getting cool air to the plastic and off the block is not easy to do and the included fan shroud is not great at providing that airflow. Granted, Slice is not responsible for how Bondtech cools parts on their extruder, still, you'll likely run into issues with any ordinary fan shroud because of the shape of this design. I ultimately made a dual fan shroud that comes in very low and cools mostly from the sides, this improved bridges immensely and gave me what I wanted - which was a noticeable improvement over the stock Prusa V6. Part cooling aside, keeping the cool part of the hot end cool and the hot end hot is what these guys do better than just about anybody. You can immediately say goodbye forever to heat creep - including and especially during very long prints with tons of retractions. The fact that the mosquito only requires retraction distances equal to the diameter of your nozzle is pretty amazing and somehow, magically effective at both controlling strings and preventing heat creep. Really impressive design there. Long story short, If you know your way around your printer, you don't mind having to work a bit for your ideal setup and have some chops at designing parts in cad, you can experience this for what it is: the best hot end in the world.

United States United States

Great Hotend because of printed solid support

I am fairly new to 3d printing and had some issues with my mk3s...I decided to take on the Mosquito install once Bondtech released their kit. Initially I tried reaching out to Bondtech and Slice Engineering for initial questions but the guys at Printed Solid were the only ones to reply. So I bought all the parts for the upgrade from Printed Solid and hassled these guys daily. Several weeks later and this hotend is printing amazing...I would NOT have been able to get it installed without the help of Printed Solid support....If these guys don't have it in stock then I don't buy it)


What are you waiting for?

Look, most of the time the "issues" you hear with the Slice Hotend is USER error. I will never use another E3D Hotend after using the Mosquito. It doesn't make your "print quality" better. It makes your printer more reliable and last longer. You don't have all the tricky assembly of seating heat breaks etc. You will not regret it and you will love it in the long run because it will save you $$$.

Guy K.

Not a perfect upgrade

Mosquito hot end and vanadium nozzle arrive well packaged and excellent condition. I purchased one from Printed Solid for testing in the BNBSX extruder. Based on multiple glowing reports on the web of how much better the mosquito works, I expected a smooth upgrade into 3D printing heaven. The reality has been considerably less. Because the hot end is also listed as compatible with E3D heater cartridges and thermistors, I opted to do initial testing with new, Prusa supplied 24 volt 40 watt E3D heater cartridge and thermistor. Both were dutifully bedded in with boron nitride. So was the Slice vanadium nozzle. Using my usual nozzle temps of 240 initial / 245 C later layers for PETG, I expected the thermal efficient Mosquito to extrude beautifully. Surprisingly PETG came out milky looking instead of glassy. Perhaps it was a wet spool I thought. No. three spools later - still milky extrusion with horrible overhang ability, and poor inter-layer adhesion continued. I tried re-bedding with boron nitride in case this was a problem with thermal paste coverage. Even with copious coverage, the milky PETG problem persisted. Increasing temperature reducing print fan speed did help a little, but black tree frogs kept printing charcoal gray and with misshapen, weak legs. Only when I switched out the vanadium nozzle for a E3D brass nozzle did things begin to look better. PETG became 90% as glassy looking as my usual E3D prints. Overhangs were still an issue. More reading found some users who discovered the Mosquito is exquisitely sensitive to any airflow bounced back from the print bed or near the hot end. I'm currently awaiting a 50 watt cartridge to see if it will deliver more heat to the Mosquito - hopefully enough to overcome the reduced thermal transfer rate from cartridge to heat block and even more reduce heat flow through the vanadium nozzle. At this point, I would not rank this as a drop-in increase in thermal delivery, but a unit that will require some work to match (and hopefully surpass E3D) capability. Thus far, I'm still working on getting it to melt filament as well as a E3D V6. That was about the last thing I expected based on glowing web reports. One handed nozzle changes ARE great, but I also want a hot end that lets me print hotter, faster and with more refined detail.

Jay C.

Top notch

This hotend has been absolutely amazing, I went from a genuine e3d v6 to this mesquito, and I've noticed improvements all around. Now I cant wait to get the magnum. oh boy!