Abstract: A urethane foam gun is disclosed in which polyisocyanate and polyol feed streams are mixed with air under pressure within the gun with vigorous intermixing in the outlet nozzle to a condition ready for application. Once applied the foam polymerizes in place. The gun is formed with an integral block design in which dual plug valves are mounted for control of the streams. Actuation is achieved by a trigger valve mounted on the gun, and a second gun-mounted valve controls a solvent flush for cleaning to avoid polymerization within the gun itself. The gun is useful for foam-in-place applications, such as protective packaging.