A semiautomatic device to hermetically seal radio-active samples in glass ampoules by a flameless method has been developed for use within an inert atmosphere glovebox. Sealing is performed by heating the open end of the ampoule with an electrical resistance heater, elevating the heated portion of the ampoule to the sealing position, and sealing the end with mechanically operated, electrically heated jaws. The method is rapid, automatic, and consistently forms helium mass spectrometer-tight seals.