using HVAC filters for a pre-enclosure?

Dan-H · Jan 27, 2018

My goal is to "bury" my linux server behind a corner unit desk, and I'm looking to avoid "dust" because it is a dust magnet. The system is a linux server, runs 24x7 and I'm looking to get it off a desk and buried behind it.

If rigbuilder returns It is my minecraft hand-me down. The system is here: https://pcpartpicker.com/b/G43Ff7

The system is not a big heat generator with an OC Dual Core G3258 and a decent tower cooler.

Case is a Rosewill Line M, and at the moment I have only one exhaust fan and temps are fine.

If I built a frame around the system so all the intake air into the case was pre-filtered through a filter, like a home HVAC filter, would this work? I'm presuming I can find a size to fit or cut one to fit.

Is there another filter that might work better? The way I think this will work is I'll have a filter that is about 6 to 8 inches wide, which is the gap from the desk to the wall, and can make it 20, 25 or 30 inches long.

The challenge will be once I bury the system behind the desk, it is about 30 mins to move the desk to get at it, but I think I can have the filter be replaceable without moving anything.

I guess I could post a sketch or pics, but my main question is on the idea in general, and if anyone has done something similar or if there are other ideas for filter material other than an HVAC filter.

Lady Fitzgerald · Jan 27, 2018

Look into DEMCIFilters. They can custom make almost any shape and sized filter which has a flexible, magnetic frame that can be installed in front of the intake fans (if the case is nonferrous, they can include a piece that sticks to the case that the filter then can attach onto). These filters filter down to 100 microns and are washable.

I designed the case I'm currently working on to take a 10" x 20" pleated paper filter but the idiot company that made the only decent one in that size cheaped out and started making them a little smaller and flimsier so I'll probably wind up making my own "DEMCI" filter.

Lady Fitzgerald · Jan 27, 2018

Stupid double posting bug. Sorry.

mattliston · Jan 27, 2018

Go to a local hardware superstore like Home Depot or Lowes' and grab one or a pack of their furnace filters. Less than $10 USD later you have a trimmable filter that only requires you to glue the edges you cut down.

I made a giant air filter box for spray painting small projects in a garage so I didnt have to deal with overspray everywhere.

plastic sheeting, glue, and perhaps a steel wire shelf sprayed with bedliner or plasti-dip could get you going and have a functional frame

Do note, many furnace filters will tend to require a lot more air pressure from fans to flow properly and not allow heat buildup. an unfiltered exhaust pathway that is sealed at the edges would help a lot here.

Dan-H · Jan 27, 2018

mattliston said:
Go to a local hardware superstore like Home Depot or Lowes' and grab one or a pack of their furnace filters. Less than $10 USD later you have a trimmable filter that only requires you to glue the edges you cut down.

I made a giant air filter box for spray painting small projects in a garage so I didnt have to deal with overspray everywhere.

plastic sheeting, glue,

and perhaps a steel wire shelf sprayed with bedliner or plasti-dip could get you going and have a functional frame

Do note, many furnace filters will tend to require a lot more air pressure from fans to flow properly and not allow heat buildup. an unfiltered exhaust pathway that is sealed at the edges would help a lot here.

Thanks for that tip. I should have unfiltered exhaust, and looking at the space more closely, I'll need to make sure it isn't looping hot air back in.

I think the only way to know is to try it, and measure the temps over time.

Dan-H · Jan 27, 2018

Lady Fitzgerald said:
Look into DEMCIFilters. They can custom make almost any shape and sized filter which has a flexible, magnetic frame that can be installed in front of the intake fans (if the case is nonferrous, they can include a piece that sticks to the case that the filter then can attach onto). These filters filter down to 100 microns and are washable.

Thanks for the suggestion. Unfortunately, I won't have any easy access to the case once the desk is moved back into place, so my goal is kindof an exo-case that only lets filtered air get to it, and have the main filter be along the top backside of the desk.

It is a corner unit with dead space behind the vertical part of the desk, and I can fit the computer back there, and it will sit on the floor but I won't be able to easily access any part of the case.

I'm pretty sure that once I bury the system behind the desk I won't want to pull it or any removeable filters out very often. I think if I use a furnace filter that I can get to easily then I"ll be able to replace it every few months if I see it getting dirty or if temps start to rise on the system.

HvacGuru · Jan 27, 2018

These would work. The aren't restive because of the size and the space between the pleates.

https://www.homedepot.com/p/Honeywe...in-x-4-in-Pleated-Air-Cleaner-Replacement-Filters-2-Pack-CF408F1625-E/202564482

Dan-H · Jan 27, 2018

HvacGuru said:
These would work. The aren't restive because of the size and the space between the pleates.

https://www.homedepot.com/p/Honeywe...in-x-4-in-Pleated-Air-Cleaner-Replacement-Filters-2-Pack-CF408F1625-E/202564482

Thanks HvacGuru. I'm not sure I can fit one that thick. I like it though.

Max78 · Jan 29, 2018

I live in probably the dustiest area you can imagine, we have dogs that run in and out while shedding all over the place and I'm finally winning the dust war!

The 1" thick pleated HVAC filters are crap and very restrictive.

There are a couple great filter medias you can use that not many people suspect. Most of the filters that I see sold for computers are wicked expensive and never worked for me. Also take into consideration that when you start to add filter media your fans become less efficient and some of the "high flow" fans become useless. I would suggest looking into some high static pressure fans if you are looking to add filter media.

Here are some great filter medias I have stumbled across.

Pantyhose
I used pantyhose on a Dell T610 server. bought the largest pair of pantyhose I could find and put them on the front of my server, it was quite hilarious and it worked amazingly well! 2 months of 24/7 running and there was no dust inside at all. This sever had I think 6 80mm intake fans running 2500+rpm at ALL times, it sounded like a shop-vac.

I also cut and wrapped pantyhose around a preexisting filter for a SFF system I built, it went 4 months without issue. My brother-in-law has that system now and he checks it about once a year and the system runs 24/7. He has a cats, dogs, and lots of dust.

this is going to be your cheapest and easiest solution to fight the dust war.

http://s35.photobucket.com/user/A_Deer/media/Supercharged Server/DSCN2375_zps92yd5dsp.jpg.html

Foam HVAC Filter
https://www.amazon.com/gp/product/B0026TBDW2/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Don't squish the filter and it has a MERV rating of 7 which is pretty good, and flow is 10 times better than any of those cheap pleated 1" thick filters.

I'm sure you can adapt this filter to the front somehow, and I'm sure it will do a great job of keeping your system clean.

I have been through a lot of different filters for our home AC system and this one have been by far the best in terms of flow and filtration.

Just some ideas from a well seasoned dust fighter. let us know what you do.

Dan-H · Jan 30, 2018

I'll have to post a picture of the space and my intentions.

I'm not wanting any filters near the case, because I won't be able to get near the system easily.

I'll have 160 to 200 sq inches of surface area for the filter if I just use the flat surface at desk height ( 5" wide by 32 to 36 inches ) Maybe I'm kidding myself, but it seems like 160 Sq inches of filter area should provide enough flow even if it is a little restrictive.

Thanks for the link on the foam HVAC filter. I might give that a try.

using HVAC filters for a pre-enclosure?

Dan-H

Lady Fitzgerald

Lady Fitzgerald

mattliston

Dan-H

Dan-H

HvacGuru

Dan-H

Max78

Dan-H

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