[sdiy] air particle filter material for a cooling fan?

[ニコラス・ケント]

I have a Voyetra Eight where the thin foam filter material that more  
or less keeps the fan from sucking in air particles has disintegrated  
from age (twice) and is itself about to be sucked in had I not  
removed it. Just curious what a decent non-disintegrating replacement  
would be.

  I checked around some computer parts shops and I guess no one uses  
this strategy any more. (and the grill is relatively huge)

  I need about 12cm x 12cm of some kind of material maybe 2 mm or  
less that freely lets lots of air in and keeps the bigger particles out.

Anyone have some extra material that would work? I'd be happy to  
reimburse you a couple of dollars.

nick kent
(in New York)