Hello!
I'm playing using K2SO and bzmods, with bztin and bzlead there is an intermediate called "solder" which is used in some recipes, like underground pipes.
Solder needs tin and lead plates, there are tin plates from the scrap all around but no way to acquire lead plates (or lead ore).
So I'm unable to make underground pipes and rocket fuel because with K2SO rocket fuel is made in a Fuel Refinery but in order to build one I need solder too lol
I saw that you created a "pipe" recipe without lead plates but instead of doing something similar in this case I could suggest 2 possible solutions:
1 - Just make lead plates something we can scavenge from the scrap like tin plates.
2 - Create a new recipe in the bioreciclying plant to produce lead/tin (in my opinion lead/tin ore would be best since it would require extra infrastructure and amp the difficulty a little, making lead plates with lead ore generates byproduct in the form of copper ore, I don't know if this would make things easier in Rubia, if so then lead/tin plates is enough :D ).