Along with working out processes for fabricating capacitors, I created some tests with aluminum tape and polyethylene dielectric (of varying thicknesses.) Capacitance measured between 2 and 3 nanofarads.

Still working out lead placement, orientation, etc.

Along the way, I created a little jig to assist with creation. Right now I'm just using the measurement sections, but I've been working on a tool at the top to assist with wrapping capacitors on the top left. Not sure if it will be hand wound or motorized.

Still trying to find the best way to affix the leads. Solder connections on the aluminum tape are not great. May be solved by dipping in sealant (wax, epoxy, resin) and drawing a vacuum on it to get rid of air.

I'll wrap up with some process pics.

Connections soldered and then covered in metal tape.

Both layers on polyethylene.

Wrapped up before being rolled.