This project set out to build a compact enclosure for a network attached storage (NAS) server. It has room for a full-size ATX power supply unit, a mini-ITX motherboard, and dual 3.5" hard drives for data redundancy.
Three years ago I started this custom computer case project to build something tailored to run FreeNAS. The primary purpose was to get some hands-on time working with laser-cut acrylic, and I learned a lot building it. Now that I’ve decided to upgrade my home server to a different configuration, there will be too much hardware to fit in this box. I’ll start with a commodity PC tower case but I might build another custom case later. Either way, this little acrylic box will be retired.
Since the computer has been sitting in a corner unobtrusively serving up files for my home network, it has also collected three years of dust. The top layer is not particularly interesting, as they were deposited by gravity. The remainder, though, serve as indicator for airflow through the system and serves as a record of comparison against my intended airflow design for the box.
The biggest lesson for me was that convection played a much smaller role than I had expected. Most of the dust indicating flow was proportional to the size of their air channels, there’s no visible sign of convection altering the flow. The most visible example is the ring of dust near the CPU fan on my front panel. I had expected it to be slightly teardrop-shaped to reflect heat rising, but it is almost a perfect circle.
The most unexpected cluster of dust is on the auxiliary CPU power cable, running to the right side of the CPU fan alongside the USB wires. It appears most of the dust there were carried by air drawn in through the front panel gap. I hypothesize that, since it is a very narrow gap, airflow through that route is slowed and thus more likely to deposit dust on that cable bundle.
There were a few minor smudgest of dust whose origins are a mystery. Two up top near the PSU fan, and one on the bottom at the rear end of the PSU. I’m curious what they were, but their fine dust particle size implies they were not a significant factor, so I’m content to leave them as mysteries for now. Maybe they’ll make sense for me in the future once I learn more about designing for airflow. In order to preserve this information (all this dust will be disturbed and cleaned up when I disassemble this box) I shot a video for future reference:
(The links embedded below are select entries from the full verbosity build blog.)
After building rev A and learning a lot about acrylic construction, I proceeded to start designing rev B. There were problems with rev A that I wanted to fix, and some additional objectives beyond that. I decided to give up trying to emulate the Apple PowerMac G4 cube and design a different airflow scheme. Some of the lessons aren't even part of the final product: I designed construction fixtures to make assembly easier.
For the moment, revision B works well for the enclosure. It has been working well enough that I haven't had to worry about the hardware. It frees up time for learning the software side of running FreeNAS on my home network.
The first draft of this project was also my first project for laser-cut acrylic. Since I didn't know what I was doing, the objectives were modest. Just build a box with all the components inside to see if it even works. And well... it didn't.
I was inspired by the Apple PowerMac G4 Cube, a beautiful landmark of industrial design. What I ended up with was a pretty horrid rendition that did not resemble the original in any way. It's my version of all those "Pinterest fails" circulating on the internet.
The angled top turned out to be difficult because laser cutter only cut at right angles. I didn't know that. I designed tabs and slots to glue pieces of acrylic together, but the sharp corners in the acrylic started cracking under stress. I didn't know that was an issue to consider. The wiring wasn't something I knew how to model in CAD, so the reality is a rat's nest of tangled wires.
Revision A was full of problems, but it was only the first draft. It's supposed to help me learn these lessons so I can apply them towards the next revision, and from that (generous) perspective it worked well.
Next up: Rev B
(The links above, and more details than you ever wanted to know, are from the full verbose build blog.)