Shopvac Filter Lid

This is a lid for the bottom of a shop vac filter 90304 . My shop vac only came with the wet/dry filter, and when I bought a replacement dry-only filter (90304) I noticed I needed the lid to completely seal up the bottom of the filter around the vacuum, so I made this. It fits in snugly but not too tight. Depending on your filter type you may want to increase the “inner rim” variable size in the openscad file to get a tighter fit.