A viscous applicator having a chamber for holding viscous fluid such as dry wall compound. A one-way filling valve and a discharge nozzle are located on the chamber. The nozzle is opened and closed using a pull rod connected to a seal on one end. The second end is controlled by a rotatable handle on the applicator main housing. A gas spring is located in the housing and retracts during loading of dry wall compound into the chamber and discharges compound when the discharge nozzle is opened by the pull rod. The handle is spring loaded to close the nozzle when released. A hollow push rod connects the gas spring to a dispensing head in the chamber and the pull rod is movable through the push rod and the dispensing head. A series of cam slots and followers controls motions of the handle and the pull rod.