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Micro piano to cassette adapter. Great condition

Pure bread dog

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

Posted by u/Cheff_excelence: If you want an air purifier but only have $39, slap a 20x20x1 (inches) filter on the back of a box fan. [Attached photo of the setup for a visual example.]

Reply by DanceUnderMoonlight: That’s exactly what these guys did in China. They even have data that proves its just as good or better than the expensive name brand air purifiers. https://smartairfilters.com/cn/en/

Reply to DanceUnderMoonlight by Kurtta: Also to add that the University of Michigan did a test on this showing how well it performs against a regular air purifier. “Build a do-it-yourself air purifier for about $25” https://www.youtube.com/watch?v=kH5APw_SLUU

[Second set of images: A box fan with two air filters attached in a “v” formation to the back of it, forming a triangle; cardboard has been taped over the opening between the filters and the fan at the top to block unfiltered air from being drawn through the fan. End ID.]

speed