The reprap project is an open source community project that aggregates knowledge "about making self-replicating machines". Essentially, many people have designed inexpensive, accessible versions of 3D printers, some evolutions of others, and have documented and shared this documentation for everyone to use freely.
The Mendel90 by nophead was a version that I was drawn to as it seemed rigid enough to provide good to excellent quality prints that I was aiming for. I opted to build the dibond version as dibond looks cool, and I wanted something that wasn't made out of plexi or wood.
Repraps are made out of a few types of materials. "Vitamins" are anything you can't print, like screws or motors. "Proteins" are the printed parts that you can hopefully obtain from someone that already has a printer in your community. Most of my parts came from eBay and Aliexpress vendors in China, though some did come from other places as availability dictated.
The dibond I sourced locally as I didn't want to deal with shipping a large sheet of acrylic laminated in aluminum. I also had the frame cut locally, out of the large sheet of dibond.
Once the parts had mostly all arrived, it was easy to follow the documentation provided by nophead in his Github repo.
The process was straight forward, similar to following Lego manuals in those big Lego sets - lots of images and matching parts up to them. Building slowly on weekends and after work took me about 4 months to complete. Total project time was 9 months, since much of the parts shipped quite slowly from China.
In the end, the cost of this project was quite high - I paid over $500 for both the dibond and to get it cut for a single frame, using only 1/4 of the dibond sheet. A smarter approach would have been to split the cost among a group of people building 3D printers, or do cut more frames, and sell the extras off on eBay.
The Mendel90 was a very well thought out design. Nophead documents his thinking throughout his own blog, and you can see much of that when assembling the printer, and when comparing it to other RepRap printers.
The dibond frame is pretty rigid, but still picked up resonance in the big 3mm panels that make up the frame. This is not a problem when printing at speeds lower than 30-40mm/s. It may be less of a problem with an all wood frame.
I've since sold the Mendel90, and parting with it was hard to do - it was a reliable printer and I enjoyed seeing nophead's thinking, process, and final design. I would build it again, and I probably will. I do have all that extra dibond have laying about.