Looking for Flat HEPA Filters for the Ultimate PC Filter

[Pork Chop]

I need help finding flat HEPA filters that can be easily cut to make custom PC filters. Most are wavy.

Air conditioner filters work okay, but let in tons of fine particles. HEPA filters are the ultimate solution because they block ultra-small particles while lettings lots of air pass through.

 

[Larry Sabo]

The wavy design is used to provide a larger filter material area and thereby reduce static pressure/provide more airflow. HEPA filters usually create a lot of static pressure, so you will need a more powerful (noisier) fan to drive air through one. (That's why HEPA filters used for clean rooms are so thick, some as much as 12" thick.) One thing I notice, is that some PCs are conflicted over air flow design, e.g., the case fan pulling air from the case where it should be pushing it in, resulting in negative pressure within the case, drawing dust in through every crevice/port. The choice of filter is moot if the airflow isn't correct.

If you are going to use a HEPA filter, perhaps try one designed for a vacuum cleaner. You will likely have to add a powerful auxilliary fan to drive air through it, though. The noise would likely make it unfeasible. Better to consider water-cooling or a more effective cooler design.

 

[Pork Chop]

The wavy design is used to provide a larger filter material area and thereby reduce static pressure/provide more airflow. HEPA filters usually create a lot of static pressure, so you will need a more powerful (noisier) fan to drive air through one. (That's why HEPA filters used for clean rooms are so thick, some as much as 12" thick.) One thing I notice, is that some PCs are conflicted over air flow design, e.g., the case fan pulling air from the case where it should be pushing it in, resulting in negative pressure within the case, drawing dust in through every crevice/port. The choice of filter is moot if the airflow isn't correct.

If you are going to use a HEPA filter, perhaps try one designed for a vacuum cleaner. You will likely have to add a powerful auxilliary fan to drive air through it, though. The noise would likely make it unfeasible. Better to consider water-cooling or a more effective cooler design.

Dang, you sound like you must have been an HVAC guy at some point.

I draw in lots of air from the front and shoot it out the back. There's a fan in the book to help suck it out. The problem is that the air being sucked in sucks up a lot of dust even with air conditioner filters.

What other filter options are there for the PC? I don't think panty hose would make much of difference and would be more difficult to work with?

I use a lot of white putty stuff from Walmart to adhere the filters so there's no permanent adhesion.

 

[Markverhyden]

Anything with a fan is going to cause airflow and that flow will take the path of least resistance. If you do not have all of the various parts of the case sealed off dust will get in that way and will not be filtered out. If you really want to be serious you need to have a sealed enclosure that is positively pressurized and the heat is dissipated outside the enclosure via a heat sink.

 

[SilverLeaf]

As Mark said, even if you have the ultimate filter system, dust will still get in if the pressure is lower inside the case relative to the outside...through PSU vents, gaps between bay covers and case panels, gaps around USB ports, expansion card slots.....

I gave up this fight a long time ago. I'll open the case once or twice a year and take in outside to blow the dust out of it if I haven't been inside of it lately for a repair or upgrade.

 

[Pork Chop]

As Mark said, even if you have the ultimate filter system, dust will still get in if the pressure is lower inside the case relative to the outside...through PSU vents, gaps between bay covers and case panels, gaps around USB ports, expansion card slots.....

I gave up this fight a long time ago. I'll open the case once or twice a year and take in outside to blow the dust out of it if I haven't been inside of it lately for a repair or upgrade.

I bought the little Data Vac blower and use it on all kinds of stuff. I blow my computer out about once per month (I'm an ultra clean freak).

Dust will still get in if not sealed, but the two 140mm Noctuas up front draw in a bajillion times more dust than little openings in the case.

I am OK with the dust coming in the crack. I'm not OK with the fans bringing in heaps of dust. The dust in the system builds up way too fast because of the fans.

Gotta have a good filter for at least the front of the case. It will cut down on the dust tremendously.

 

[Pork Chop]

Anything with a fan is going to cause airflow and that flow will take the path of least resistance. If you do not have all of the various parts of the case sealed off dust will get in that way and will not be filtered out. If you really want to be serious you need to have a sealed enclosure that is positively pressurized and the heat is dissipated outside the enclosure via a heat sink.

Lots of air sucked in in the front and sucked out the back = positive air pressure? It makes air stream right through the case.

 

[Markverhyden]

Lots of air sucked in in the front and sucked out the back = positive air pressure? It makes air stream right through the case.

Because it is not truly sealed it's probably neutral as a system if the fans and filters are all the same. The only way it would be positively pressurized is if there is an intake fan and no exhaust fan and/or large openings.

 

[Pork Chop]

Because it is not truly sealed it's probably neutral as a system if the fans and filters are all the same. The only way it would be positively pressurized is if there is an intake fan and no exhaust fan and/or large openings.

Wouldn't it be disadvantageous to not have an exhaust because the incoming air needs to escape? Without an exhaust, the intake would suck in dust and the dust would have nowhere to exit the case - it would accumulate faster.

 

[Larry Sabo]

My advice is to reverse the case fan so it blows into the case, not sucks air out from it. That will create positive pressure inside the case and keep the dust out--if you put a filter over the case fan. The PSU sucks air out so the air blown into the case by the case fan will exit through the PSU and the little cracks and crevasses between ODD, etc. I did a lot of reading on HEPA filters when I was designing my DIY clean chamber.

 

[SilverLeaf]

My advice is to reverse the case fan so it blows into the case, not sucks air out from it. That will create positive pressure inside the case and keep the dust out--if you put a filter over the case fan. The PSU sucks air out so the air blown into the case by the case fan will exit through the PSU and the little cracks and crevasses between ODD, etc. I did a lot of reading on HEPA filters when I was designing my DIY clean chamber.

Nice build Larry! Is that unit still in service?

 

[Larry Sabo]

Nice build Larry! Is that unit still in service?

Thanks! Yes; it was completed just 7 months ago. Works great!

 

[Markverhyden]

Thanks! Yes; it was completed just 7 months ago. Works great!

Yes, very nice. I always like it when someone goes the extra mile to make something sophisticated rather than just buying off the shelf.

 

[Larry Sabo]

Thanks, Mark. It was the cost of commercial laminar flow benches (over $1,000 CAD) that motivated me to design and build it myself. Mine cost me just $275 CAD plus a couple of weeks of part time effort. Given how little I need to use it, it's more than adequate.

 

[Altster]

Years ago when dot-matrix printers were the "norm" many 3rd-party manufacturers built enclosures for the printers to sit in - to help reduce noise and to keep paper dust, what-have-you, to a minimum. I recall seeing many rather large boxes which had hinged covers and at least 2 fairly powerful fans (1 with incoming air and 1 with outgoing air) so that the airflow was always positive. I suppose something like that could be built as a custom-computer cabinet which would allow the OP to install HEPA filters to keep the unit clean.

Of course there would be a need to calculate the air circulation force(s) in order to ......................... (too technical for me - LOL)