To craft 8 (blocks of) Hardened Lava Walls at a time you'll need (as of R29 in February 2016): * 4 Hardened Lava (blocks) mined from the Lava layer with at least an Iron Mining Cell equipped * 2 Iron Rods (made from Iron Bars in a Processor) * 1 Glob of Goo (made from Mold in a Processor or looted / harvested from many animals/pets) * 1 (block of) Igneous Rock mined from the Lava layer with at least an Iron Mining Cell equipped