Abstract: A sintering furnace includes an upper housing having a gas permeable insulating enclosure therein, with heating elements within the enclosure, and a lower housing having a hearth against which the insulating enclosure rests. Sweep gas is introduced to the interior of the upper housing, outside of the insulating enclosure. The sweep gas flows through the porous enclosure, past the pieces being sintered to sweep organics away, and out of the enclosure through an organics sink post extending upwardly from the hearth. The sink post is hollow and has openings therein, and is in communication with an external trap and vacuum pump, so that the organic-laden sweep gas is drawn out of the furnace. The insulating enclosure includes a gas barrier having openings therethrough and insulation layers on either side, the openings being sized such that the flow of sweep gas prevents diffusion of organic vapor out of the enclosure into the upper housing.