This is quite simple, a 120mm PC fan is attached to a stand. And has some nails placed in it to hold the carbon filter, for easy replacement.
- 120mm fan, easily scavenged
- 4 nails
- carbon filter, a 3 pack is $5 at DigiKey
- 1/8" thick polystyrene or acrylic or Masonite
- Methylene Chloride (acrylic cement) for styrene & acrylic or wood glue for masonite.
-Acetone will work for acrylic and styrene, takes longer though, look around online for info
- Drill and bits
- Something to cut a hole out.
- a Band Saw, Jig saw, rotary tool, hole cutter, key hole saw
UPDATE: Added a better air hood and painted it black. Added the images and notes.
Step 1: Cut the Hole
Without this front piece air was deflected back out between the edges of the fan blades and housing. This helps keeps that from happening to much, and creates a much better suction.
Cut a 12 cm x 12 cm square of styrene, acrylic or Masonite. ( 4.5" x 4.5" works fine )
Draw lines diagonally, corner to corner.
Use the center point to draw your circle, with a compass or however you draw circles. 4.25" diameter circle worked for my fan. It should overlap the edge of the fan blades, blocking the gap between blade and housing.
Depending on what medium your using (styrene, acrylic or masonite). Choose a good tool for cutting out the hole. I used a band saw and just cut into it from the edge, and I had to glue the cut closed again. It doesn't have to be pretty, just keep it pretty close. Then clean it up with a file or sand paper.
Place the fan on the circle and mark where the mounting holes will go.
Find some screws that fit your fan's mounting holes, then choose your drill bit. Drill them out.