A refractory paddle mixer delivers fast mix times while working with mixtures that include aggregates up to 0.5 inches thick. The hydraulic machine mixes as much as 500 pounds of refractory castable in 1.5 to 2 minutes and performs well in form-and-pour jobs and other applications involving precast shapes, mortars and grouts. Its oversized, heavy-duty, chain-and-sprocket drive system provides years of reliable use under harsh conditions. The mixer also features a pair of easily accessible levers to control the hydraulic dump and operate the system in both forward and reverse.