NOT SPOILER-FREE

Weiss, Weiss... :[

Commission for @/Jeanjim77 on Twitter, thank you ! Drawing Jaune as the Rusted Knight takes a LONG time-

Commission for @densharr!

Lancaster Commission for TMan_2018!

Another design is using 2 20x25x1 filters, taping them to the sides of the box fan and then to each other so they sort of make a triangle, then cutting cardboard to make a top and bottom to the triangle.

This was discovered as a more effective design during the 2020 US west coast fires.

https://tombuildsstuff.blogspot.com/2013/06/better-box-fan-air-purifier.html

Another design is using 2 20x25x1 filters, taping them to the sides of the box fan and then to each other so they sort of make a triangle, then cutting cardboard to make a top and bottom to the triangle.

This was discovered as a more effective design during the 2020 US west coast fires.

https://tombuildsstuff.blogspot.com/2013/06/better-box-fan-air-purifier.html