Thought I was in genmay for a sec with this title.
O, yeah, what guy above said. 2x4 can certainly work. You can also buy just rails fairly cheap online and bolt/screw those to a wooden frame.
Are you thinking sideways airflow, or vertical? With only one server and ups, front to back flow may be easiest and you can get away with a considerably smaller filter.
I bought a cheap filter holder online for only a couple dollars more than the wood to make a frame. Very easy to change the filter with.
Note, home style filters can be darn restrictive. May have to use a poor mans cheesecloth on grate if you are running quit 140mm fans for ventilation.
Not sure how I want the airflow to go. All told I will have a 12 drive cage with my Plex hardware, two PDU's, and APC 3000XLM with four battery expansion cases. I'm considering taking the dual Xeon board out, and putting a retired 3570k in - since it would be a lot cheaper to operate. If I do that, I won't be able to put the top on (the only cooler I have for it is a noctua, won't fit), and thus clean air becomes absolutely critical. This rack is going in a hostile environment - my garage. Dust will be a serious, serious problem.
Noise tolerance is pretty high, because yes, I'm running server fans now. This will be a much quieter solution for my house. I would just rather not suffer a dust arc or short. I also need to keep some clean airflow over the HDD cage. Lots of drives, lots of data.Ah, then you want to go with filtered positive pressure. Hard to make a negative pressure case air tight with wood in an environment like that. Not that you can't, just gets more time consuming and difficult.
What's your noise acceptance level? Are you running server fans that are already stupid loud? For this kinda thing look for an industrial or commercial fan maybe? Though those batteries and UPS won't be adding much heat.
The higher duty fan will give you much better reliability, airflow, and static pressure. With much higher noise usually.
Noise tolerance is pretty high, because yes, I'm running server fans now. This will be a much quieter solution for my house. I would just rather not suffer a dust arc or short. I also need to keep some clean airflow over the HDD cage. Lots of drives, lots of data.
Ok. Not sure what kind of monitoring you have setup, may want to at least have a heat detection shut down setup.
On the cheap, you can set a box fan to pull through a regular air filter. If I was going to run that in a garage, I'd make a small plenum box so I can mount at least 3 filters on different sides to increase the surface area.
Just sucking through one filter cuts most box fans down to like 3oo-500cfm. Increasing the surface area greatly may get you back up to 1,000.
Running a $150-200 metal blade commercial fan would be much safer and a wise choice for the kind of stuff you are trying to protect. I'd still run a filter box with multiple filter faxes just so I wouldn't have to change the filters as often.
I have unused commercial fans from when I was cooling a bunch of gear before. They can move enough air to knock a cat over if it walks in front of them. I think I might use a dual-filter design - for large and fine particulate. If I put a screen around the intake of my fan for the big stuff, and then a finer filter between the fan and the box, that'll probably do nicely. Even restricted, each one of those fans has enough cfm to replace the entire volume of the box a few times per second.