A baffle includes a base and a seal having flexible segments which engage a mold structure. The base of the baffle may have a noncircular opening in which article mold portions of the mold structure are disposed. The baffle may be connected with the furnace assembly before a mold is moved into the furnace assembly or may be connected with the furnace assembly as the mold is moved into the furnace assembly. A projection connected with the mold structure may be utilized to orient the baffle relative to the mold structure. The projection may be a thermocouple assembly which extends from the chill plate. Alternatively, the projection may be a portion of the mold structure itself.