4" Shop Air Filter

thingiverse

EDIT: Changed inner diameter of filter-base.stl to be a better fit on the blower. Attaches Directly to a 4" blower like this: https://www.amazon.com/gp/product/B06WGR78YZ/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 Secure the base to your blower using 2 #8 or 4mm screws and nuts. Use 1/4" dowels or rods to tie the pieces together. Take the filter sheet from a 20"x20" furnace air filter and wrap around the outside, securing it with some string on the ends and on the middle brace. The end result should be a compact air filter!