Abstract: A coating liquid is squirted through a needle control nozzle directed into open end of internal threads of a fitting or tube and is deflected radially to form a spray cone by an air jet from a revolving nozzle set slightly in front and off the axis of the nozzle for the coating liquid. An end plate affixed to the revolving nozzle limits the forward spread of the spray cone, so that the coating thickness taper is cut off at the inner end of the coating on the threads. The thickness taper produced at the outer end of the threads by the spray cone favors easy engagement of the threads in making a tight threaded joint.

Abstract: Liquid sealant is applied to threaded parts that are to be connected by screwing or fitting together in a gas- or liquid-tight manner in a uniformly thick coating and the coating allowed to harden, so that the parts may be stored indefinitely before use. The coating is applied by an application tool which has a similar threaded shape to the part to which the coating is to be applied and which is provided with outflow openings in its surface.