After building the Mendel90 3D printer, I knew I wanted a second 3D printer so I could print two different types of plastic without having to swap hotends to do so. I also knew that I wanted to pay much less than I did for the Mendel90. A group build made sense to split the cost, and it was a good opportunity to run the build with the local maker community to help me learn to do so more similar events.

The Printer

The P3 Aluminum is an evolution of the P3 Steel RepRap project, modified by a friend to use aluminum and different printed parts. Neither the P3 Steel nor the P3 Aluminum were as well documented as the Mendel90, but I was able to lean on my friend, who'd gone through a group build a year earlier.

The Parts

Parts were ordered through eBay and Aliexpress again, from Chinese vendors. We sourced sheet aluminum, fasteners and rods locally. Total cost for this printer was expected to be $700 per printer, and ended up at just over $550 CDN each for 7 people.

aluminum parts


Assembly went much faster as a result of the pressure of wanting a complete printer for the group to be able to reference. Once the parts were here and I printed the parts I needed on my Mendel90 (while I still owned it), putting it all together was a snap.


Wiring was a bit of a chore since there was no related documentation. However, using JST connectors and crimpers at the advice of my friend made for a solder free build. I highly recommend you take this route for fast, clean wiring.

Printing Parts

Since I had the only 3D printer in the immediate group, I undertook the task of printing parts for all the printers.

printed parts

I ended up with one of the P3 Aluminum builds from my friend's group build last year, and printed the majority of the parts on it in ABS. I was running 8 hour or longer prints (up to 12 hours) back to back on it, with great quality and success. It was a great test of this printer's capabilities.

more parts


This is a really nice printer for the money. The interlocking metal panels provide a sturdy design, and the 3mm aluminum has much less resonance than the dibond I chose for the Mendel90. I ended up using smaller motors on the P3 than I did on the Mendel, which means less torque but also less noise. I don't miss the torque at all, though I might if this was a CNC.

the printer

We bought $100 electronics kits from eBay that included everything electronic. The bed is great for PLA, but using it at higher temps was a problem - It has trouble reaching 110C, and heats up quite slowly. I'm soon replacing the bed with an etched one made to spec in the search for faster heating and better thermal stability at higher temps.

old bed

Wiring is not as tidy as the Mendel90, and the project isn't as well documented or detailed as nophead's project. There definitely was much more to think about and plan for this printer, which made for a good learning experience.

My repo of the P3 Aluminum project.