Abstract: Provided is an apparatus for circulating a body of molten solder. An enclosure, attached to the base of an impeller motor extends downward into the body of molten solder. A rotatable shaft, advantageously attached to the impeller motor by a flexible coupling device, extends through the interior of the enclosure, terminating beyond the open end of the enclosure and connected at that end to an impeller. A seal between the rotatable shaft and the open end of the enclosure acts to prevent solder from entering the interior of the enclosure. The seal is comprised of a self-lubricating material which expands as the temperature of solder increases, forming a solder tight fit between the rotatable shaft and the seal and further securing the exterior of the seal to the interior wall of the enclosure while permitting shaft rotation. The self-lubricating and high temperature characteristics of the sealing material preclude the production of by-products from wear by the rotatable shaft.