Abstract: A method of applying a refractory castable onto a surface of a refractory structure, comprising the steps of: [a)] preparing a thoroughly mixed wet castable for application onto a surface of a refractory structure; [b)] conveying the wet-mixed refractory castable at a set rate under pressure through a delivery hose having a predetermined cross-sectional area to a dispensing device having an air inlet and a dispensing nozzle; [c)] introducing air under pressure into the dispensing device, wherein the air pressure ranges from about 20 psi to about 80 psi and wherein the air has a velocity of about 177 ft/sec at 20 psi and an air velocity of about 484 ft/sec at 80 psi and wherein the velocity increases by about 5 ft/sec for every unit increase in the pressure.