I designed this fume extractor because I had a handful of 92mm fans in my shop. There is a cut-to-fit carbon filter sandwiched between two grills.
To build this, you must print:
1x Spacer (there are 4 in the .stl) or 1x Spacers-With-Gasket
I've included the Fusion 360 file for your enjoyment.
EDIT 10/26/17 Added a new version of the spacer that seals up the filter area for better suction through the front, at least theoretically.