Powercord originally had a filter just like the one that this project is based on. I have to admit that when I took ours apart, I had the same thought as the author of this one. Wood frame: check. Another fan: check. Filter media: check.
Qty (1) Fantech Inline Exhaust Fan, 392 CFM, Centrifugal for 6" Duct Qty (1) 29500 Honeywell Air Cleaner Replacement Filter Qty (2) 3M Filtrete Air Conditioner Filter, 15-Inch by 24-Inc Qty (1) Duck Brand 1285234 24-Inch by 15-Inch by 1/4-Inch Foam Air Conditioner Filter Qty (1) 55lb bag of activated carbon (I called them and spoke to Karrie Gibbons. Just ask for "4 by 8 coconut shell carbon, for vapor filtration") Qty (1) Harbor Freight Router Speed Controlled Qty (1) Roll of squishy neoprene shelving liner (It's about 1/8" thick, soft, makes great gaskets) Qty (4) 2inch casters Qty (1) 3/8" Romex clamp or cord strain relief Qty (4) 3/8inch threaded rods Qty (8) 3/8inch nuts Qty (4) 3/8inch wing nuts Qty (8) 3/8inch washers Qty (1) 5' roll of window screen Qty (1) 5' roll of 1/4" wire cloth Qty (1) tube silicon caulking Qty (1) 3/8" dowel pin (for the router jig) An old extension cord (we only need the male end) 4'x4' piece (half a sheet) of 3/4" thick birch plywood smooth on both sides. Mat board Weather stripping (I had leftovers from other projects, but basically 1/4" thick, foam) Qty (1) Roll of post filter material (updated!)