Charcoal Forge

The Charcoal Forge is a device used to heat and melt items. Forges are necessary to make a crucible work. They are typically used to heat items to prepare them for smithing on an anvil.
It is constructed with 5 stone blocks surrounding a charcoal pile of 7 or 8 layers which is then lit.

A Charcoal Forge

A complete forge multiblock, ready to be lit.

A Forge needs a chimney in order to work. The block directly above the Forge must be air, or a Crucible. In addition, either the block directly above, or one of eight nearby blocks must be able to see the sky - the blue stained glass in the visualization to the right.

A Bellows can be placed on one block up and adjacent to the Forge, in order to increase the maximum temperature it can reach.

The five slots at the bottom of the forge are used for fuel. While the forge is running, it periodically consumes fuel, which can be Charcoal or Coal. The top five slots will heat items, up to the temperature shown in the indicator on the left. The right side slots are for containers that can contain liquid metal, like Vessels and Molds. Items that melt in the forge will fill those containers.