need a forge. crucible and something else i dont remember
Crucible and Charcoal
Edit: Charcoal is Wood + Fire.
Crucible is concrete + stone / gravel + clay (if you do "gravel + clay" put the gravel in the left slot and the clay in the right or you'll get a whetstone) / concrete + sand / clay + stone / gravel + concrete
Concrete is gravel + water
Gravel is stone + electricity
Clay is water + sand
And sand is stone + water / stone + air