120mm activated carbon filter

This is my design of an activated carbon filter for a 120mm PC fan. This is a modular design and is built up on stages. I used 3 stages for my filter. Each stage is 15mm height and held together with m3 screws. Additionally parts: 2x m3 nuts for the fan mounting and 2x m3 screws for every stage some sort of mesh activated carbon 120mm PC Fan Assembly instructions: mount the first stage with the grid facing down onto your pc fan with 2x m3 screws and 2xm3 nuts. (screws into the holes, nuts from the bottom) cut out a thin mesh circle with a ca 1.5cm bigger radius than the filter (i used Cotton mesh from a shopping bag) put the mesh into the first stage so that the edges stand up like shown in the picture add activated carbon pellets If you plan to remove the fan without taking the filter apart, put something into the holes of the first stage above the screwheads so they don't fall in if you unscrew the fan underneath with the upper stages on top. if you like you can put some mesh between