|This article is about the current version of DF.|
A Magma smelter is a special variation of the basic smelter that uses magma as a source of heat, instead of fuel. Like all magma-powered buildings, it is not visible under the Build menu until your dwarves discover a source of magma.
To function, magma smelters must be built with at least one of the eight edge tiles occupying an open space with at least 4/7 magma on the next floor down. This magma can be natural, or channeled from a larger source, or otherwise transported from another level to a trench designed to hold the magma.
If the only opening to the magma is under the impassable tile of the smelter, then magma creatures won't be able to enter the workshop area through the opening; otherwise they can.
Magma smelters do not consume any magma from their magma source - you can use a single tile of 4/7 (or deeper) magma below the smelter as an infinite heat source.