I made an interesting discovery when building my current project. I had bought some of the large BitFenix 230mm (200mm) fans in white. Painted the edges black.
Then I ran into a problem. I needed a dust filter.
In southern Colorado we're desert, it's dusty here no matter what you think you do to keep the dust down, it is always around. Not to mention the girlfriend likes her cats, and the cats like my desk because it's big and flat and warmer in that area thanks to my desktop, a minecraft server, and 3 monitors.
I then realized that it was impossible to find a filter for those fans, or even really a filter that big. Also these fans, and all the bigger BitFenix fans are oddly shaped once you get above about 140mm...Then an idea dawned on me based on a trick from back in the '90s and this was born:
Back in the 90s when I started building in this dust hole when I was a teen I wanted filters and one way to do it was to get some cheap panty hose and stretch them onto some kind of form and secure them somehow. Well because of how BitFenix builds these fans they are suited for this trick like icing is suited for cake.
Comes out looking nice and clean and works for their small ones like the 140mm almost as well. All the Spectre Pro fans come apart with the shell and inner fan being separate. Basically all you do is take the fan apart, stretch the material over the center, and clip the housing back into place.
Once they are clipped you trim the excess material off around the edges and because it is panty hose it will tuck itself in nicely giving a relatively clean edge.
Just figured this could help anyone else looking for a way to filter these large fans. Takes about 5 minutes, costs all of $2-6 depending on what quality of nylons you go with. Oh and a few slightly awkward looks from the store associate if you are male.
*EDIT* Looks much better in person than in the pics btw.