I am a woodworker with a large inventory of scraps, so I made mine with wood. However if your are more of a duct tape person, the same filter could be made that easily.

I won't go too deep into the woodworking phase. If you have the tools, materials and skill set there is little I can tell you that you cannot clearly see for yourself. I did figure out that the fan is much better at sucking the air through the filter than blowing it through. Put the fan blowing out the front with the filter in the back.