@Tfmonkey You've said this error twice -- sodium nitrate is not what you need for black powder. Potassium nitrate is what you need. And it is what you get from piss.
The only ingredient I'm stocking is sulfur, because it's more difficult to come by naturally.
Charcoal is easy to make. Here are snapshots from my personal notes.
First, the ingredients:
@RoninGrey Such nice hand writing
@TenaciousWolf It does have a "mad scientist" vibe, I think.