An applicator for mixing and applying multi-component compositions to a work surface, such as two-component surgical sealants. A luer hub sub-assembly having a proximal hub and a distal hub, an elongate, four-lumened cannula, and a spray tip sub-assembly are provided, with interconnections between the sub-assemblies preserving isolation of the fluid components from one another. The tip cap sub-assembly includes registration structure to assure proper alignment between tip cap and tip insert. The end wall of the tip cap includes a spinner region with three feeders or feeder channels leading thereto, the fluid components remaining isolated from one another in two of the feeders or feeder channels, and initiating mixing with one another in a third of the feeders or feeder channels.