Some Wire Mesh/Filter/Fan Grill Testing...

[ScottAllyn]

I originally posted this to Cutless009's Project "Formal Black" thread but a few people have suggested that I make a stand-alone thread out of it, so...

I'm working on a new build and plan to use wire mesh for my fan filters. I've had good results with store-bought wire mesh filters in my current Antec900 build (which uses the filters in column #12 in the table below) but I wanted to see if I could find something with a finer "weave" for trapping some of the smaller dust particles that still get into my system. I have some 100 x 100 copper mesh here at the office, which I'm sure will filter out all but the finest dust particles, but it's pretty restrictive on the air flow and creates a *lot* of wind noise. Fan noise BAD! I have become more appreciative of silent computers in recent years.

McMaster Carr has a huge selection of wire meshes, so I ordered a bunch of 12" x 12" mesh samples from them, created a wind tunnel (or sorts) out of old/junk 120mm fan bodies (can you say "SilenX"?), and went about testing the meshes once I received them. Here's the results:



...and a few photos of my crude little wind tunnel and the meshes/grills (click on 'em for larger images):



For each mesh/grill, I noted the anemometer reading with the filter installed on the intake side of the wind tunnel and then again immediately after removing the filter. There's some turbulence inside the tunnel which caused my anemometer readings to bounce around a bit, so I just averaged out the numbers over a period of a few seconds and noted the before/after numbers for each mesh.

As I mentioned above, the main thing that I wanted to check with these meshes is their noise level with the Scythe S-Flex fans but figured that, since I actually have a little anemometer, I may as well check the air flow. Almost all of the meshes/grills are noisy when installed directly adjacent to the fan body, so I used an extra fan body as a shroud - made a world of difference, especially with the Ultra Kaze.

Here's a close-up of some mesh swatches to show (more or less) their "transparency" level (Click the image to see *all* of the swatches in the full-size photo):



I didn't have any time to set that photo up, but it looks about right. The swatches are the first 10 meshes in the table above, in order from left to right, top to bottom.

Here are some shots of the various store-bought filters/grills (click on the thumbnails to see a larger version):




If you're wondering about filter #13, that's the filter from the bottom of a Cosmos S case and it is yet another casualty of the Ultra Kaze fan - that thing is a menace!

I'm probably going to go with the 43 x 43 mesh for my own case (mostly because I already have 12 feet of it). It's a tight enough weave that it should keep most of the pet fur and much of the dust from entering the case, yet it still allows for good airflow and won't create any extra wind noise in my setup. If I didn't already have all of that 43 x 43 mesh, I'd probably go with the 60 x 60 (or the 70 x 70), which'll catch even more dust and still allow for decent air flow.

That copper mesh is too restrictive - even without looking at the numbers, you can just *feel* the difference at the end of the wind tunnel. With that weave as tight as it is, it won't take very long to build up an accumulation of dust and fur, which'll make the mesh even *more* restrictive - it'd probably require daily cleaning and I'm waaaay too lazy for that!

I'm sure there are flaws in my setup and test procedure but it told me what I needed to know - maybe it'll be useful to you guys.

11-Dec-2008 Notes:
I added the MeshX FanGuard, the fabric softener sheets, and the pantyhose. I can safely say that an Ultra Kaze has no trouble tearing a Snuggle fabric softener sheet to ribbons; at least it wasn't my finger this time.

The fabric softener sheets are more restrictive than the wire meshes and, after looking at them closely, I really don't think they'll do as good of a job at keeping dust and pet fur out of the cases. The sheets look a bit like a sheet of cob/tangle web that's been soaked in fabric softener "goop". There are areas full of relatively large openings and then areas where the "goop" clogs the openings. I'd worry about that stuff getting sucked out of the sheet and blown into the case. Then there's the smell... I know some of you guys like the smell, but it makes me sneeze. I tested them about an hour ago and my nose is still running.

The pantyhose performs quite well, tho it's very dependent upon how much you stretch it. If you don't stretch it at all, it's way too restrictive and'll probably kill your fans in no time. For my test, I stretched it to the point that the openings between the threads were approximately the same size as the openings in the 70 x 70 wire mesh (as judged by my eyes). I have no doubt that this will stop dust, but so will that 70 x 70 wire mesh and I think the mesh looks nicer (at least on the case).

13-Dec-2008 Notes:
Vapor made a comment that he thought the fabric softener sheets were supposed to be used (run through the dryer) before using them for fan filters. I was wondering about that when I tested them since they were clearly clogged up with the fabric softener, but some of the guys had mentioned liking the smell... so I figured I'd test them fresh out of the box. I've since soaked sheets from both brands in hot water, rinsed them thoroughly, and let them air dry. This, obviously, isn't quite the same as running them through the clothes dryer but it's about as close as I can get - I'm not going to throw them in with my clothes since fabric softener makes my skin itch.

The "used" sheets are now completely free of fabric softener (yay... no more stinky aroma!) and have actually shrunk a little bit. There's a much higher percentage of open areas now which are slightly smaller in size, due to the sheet fibers tightening up. I'd say they'll do a good job at trapping dust and pet fur. Both the Bounce and the Snuggle sheets look the same after washing out the detergent, so I only tested the Bounce sheet - check the chart above for the airflow numbers.