Special insulated pipes are now required for transporting molten iron and copper between foundries. Much like plasma from fusion reactors and generators, these pipes are incompatible with normal fluid pipes and therefore can't go underground or utilize pumps for long distance transport. This is intended to add some extra challenge to balance out the massive rewards associated with using foundry recipes. As an added bonus, molten fluids in insulated pipes are also slightly brighter and faintly glow in the dark

NOTE: Due to the way pipe categories work as well as some foundry recipe inputs and the offshore pump utilizing non-molten fluids, raw lava can be transported in normal pipes into foundries and water, Fulgora oil, and ammoniacal solution can be transported from offshore pumps into insulated pipes. Given the niche nature of the former case and the uselessness of the latter cases, this behavior will currently be kept as is.