Graphite felt and graphite foil not hard to source but also not extremely common

Finding the right pumps/tubing took a lot of trial-and-error, but it's fairly easy to buy from the supplier and I reckon we could find a replacement supplier. The porous separator material is the other one - matte photopaper works, but finding purpose-built battery separator in small quantities is very hard, you have to ask companies for research samples. It's not expensive, just not a thing it's easy to get.

Me too 😅 it's mostly water though so that helps