Getting ready for the next wildfire season.
This is using MERV13 filters from Amazon as well as the guts from some well-made fans.
The cut is dependent on the thickness of the used plywood. To generate DXF file, OpenSCAD needs to be installed. Then, measure the actual thickness of the plywood with calipers.
Let's assume we measure 5.7mm. Then this command will generate the necessary DXF file:
make air-filter-cuts-5.7mm.dxf
As an example, there is a 5.5mm size pre-generated air-filter-cuts-5.5mm.dxf in this directory.
Everything is in one big DXF file of which probably parts have to be disabled to cut one at a time on a normal-sized laser cutter :)
To laser-cut, it is probably good to use an inward kerf correction for the finger slots.
Glue in top and bottom filter stopper (shown in blue below first).
Corner parts have to be slotted together length-wise, then the bottom and top finger joints fit exactly with the corresponding top and bottom plate.
Corner parts can be glued.
If things look like this, PM2.5 is probably high, and it is good to have
such filter:
