Abstract: This percussion welding power supply supplies welding energy through an arc between two work pieces that are forced together during or immediately following arcing. The power supply comprises a welding transformer having a primary winding and a secondary winding. Across the secondary winding, welding electrodes are connected for supplying welding current between the secondary winding and the pair of work pieces to be welded together. The power supply further comprises a capacitor bank having a pair of output terminals and means comprising electronic switching means in series with the primary winding and the output terminals for selectively connecting the output terminals across the primary winding. Control means is provided for rendering the switching means conductive, thereby causing the capacitor bank to discharge through the switching means and the primary winding to effect a welding operation.

Abstract: Discloses a method of applying an amorphous fused silica coating to a substance of refractory non-metallic material. High temperature arc plasma from an arc plasma spray gun is projected onto the substrate surface; and particles of a material consisting essentially of crystalline silica are fed into the plasma, where they are melted and entrained in the plasma. The gun is held close enough to the substrate to effect melting of the surface of the substrate, or the previously-applied material, in the region where the molten drops of silica entrained in the plasma are impinging against said surface.