Before getting into the details of the build, I want to highlight one big design change since the last posts were published. The original intake baffle design was severely limiting the airflow because of the small inlets. A keen redditor suggested that by making the pressure drop over a larger surface area (i.e. making the filter bigger), the fans would be able to move more air, more easily. To accommodate this, I moved the filter to a shadowbox on the outside of the front door, and sized it to take a standard AC filter. The bottom of the shadowbox is open and fits over a hole in the base of the rack. The intake baffle is a “U” shape, pulling air down through the hole in the front, around the bend, and up into the interior.
This post is intended to serve as a step-by-step guide for anyone who wants to build their own rack. All of the necessary drawings are available as PDFs (black and white with dimensions and color), as is the full Fusion360 project. I have a limited amount of woodworking experience; however, this project was very accessible because there were no advanced techniques or joints, just a lot of cutting, gluing, and fastening. Confidence with powertools is definitely necessary.
The final Fusion360 drawing can be found online here, and an archive file of it here
The most frequent comment I saw about Part 1 was concern about airflow. I had always planned on doing some kind of rough testing, but seeing the extra concern, which I already shared, I decided to do something a little more rigorous.
The goal is to ensure that in the closed box, the intake baffle provides at least as much air as is drawn in through the intakes of the racked devices. In my case, the biggest is an R720XD, and the rest are insignificant in comparison. The difficulty is that not only does the baffle itself restrict the airflow, but the dust filters do so even more.
The fans I used first were Apevia AF58S-BK 80mm case fans because the 5-pack was only $15! Only after I started testing did I notice that these are “silent” fans…
We recently moved into a new condo with an attic, which gave me the opportunity to relocate my server rack out of the guest bedroom closet and into a room where the fans spinning up won’t wake people up. Until now, my homelab has continued to live in its Startech 12U rack, but I quickly discovered two problems caused by the attic being an exterior room: first, it’s extremely dusty, and second, it’s not insulated. When its about 80°F outside, the temperature in the attic gets up to 100°F, even with proper roof ventilation. This causes my R720XD fans to spin up. To the max. Which I can then hear through the entire house. With all the doors closed.
In the interest of homelab longevity, I don’t want to force lower fan speeds. In fact I’d like to run them at the max all the time, but of this makes the dust problem even worse too. The solution: a custom, DIY server rack.