Phaetus Rapido review – A super High Flow Hotend

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I have two 3D printers: a Prusa i3 MK3S+ (the workhorse) and an Ender 3 V2 (my fidget printer).

Lately, I’ve been working on “Project Hurricane”, turning my Ender 3 V2 into a 1000 mm/s speed deamon printing at flow rates pushing 50 mm^3/s.

The first major upgrade to get there… a high flow hotend. Or in the case of the Phaetus Rapido an “are you kidding me” flow hotend.

My Phaetus (without the silicone sock) looking good in the HeroMe Gen 6 cooling system.
Here’s the High Flow (not Ultra high flow) Phaetus Rapido installed on Project Hurricane. I like the box…
A picture of the (assembled) Ultra High Flow Nozzle for the Phaetus Rapido
A picture of the (disassembled) Ultra High Flow Nozzle for the Phaetus Rapido

One thing I like about the Ultra High flow design is this E3D Volcano length nozzle. To account for the extra length they include a nut/sleeve to help maintain some thermal mass. It’s clever.

My friend Nathan, of Nathan Builds Robots, did a great review on this hotend.

How fast does the Phaetus Rapdio heat?

SO FAST… I was stunned. On my stock hotend I’d set it to heat and wait several minutes.

On the Phaetus?

Turned it on, set to 200°C, and watched (each interval was about 3-5 seconds):

22°C. 35°C. 80°C. 150°C. 212°C (overshot… see the important tuning the PID section below).

How difficult is it to install the Phaetus Rapido

Plan on a multi-hour conversion if you’re installing it on a Creality printer (such as the Ender 3 V2) as the Phaetus uses a “V6” style mount.

This means you’ll need to buy/print a new mounting system for the Phaetus, so I took that time to upgrade my fans to the HeroMe Gen 6 cooling system.

Note: I chose the HeroMe because it explicitly supports the Phaetus. However, the build sucks so hard that I’d recommend trying the compact “Manta” system for a Creality Ender 3, 5, or CR 10.

Once mounted the rest of the build was pretty easy. I spliced in new wires using red quick disconnects, auto-tuned my PID (see below), and was good to go.

How to autotune your Phaetus PID

This is the guide I used to tune my PID on the stock (Marlin) firmware.

If you’ve already upgraded to Klipper then I’m positive you could handle this without my help.

Photo of author

Garrett Dunham

Garrett chose his University because they had a 3D printer... back when they were called "rapid prototypers". Here's how he builds Ender 3s that can print 1000mm/s for less than $600.