Why not just molten iron and molten copper instead of Steel bar and molten copper?

In my mind the steel plate goes inside the heat pipe. Could add an option to change this though.

That should work! :D
Main idea with "casting end items" is just making it easy with inputting the molten metals and output the end product that just require "those molten metals and maybe skip an intermediate", like, in this case, skip the molten iron to steel bar.

I extended the mod settings to support this. Thanks for the suggestion!

Amazing implementation! Fully customizable!
KUDOS