A microwave plasma drill

A technique has been developed for melting holes in masonry as an alternative to conventional drilling. Microwaves are applied to a tungsten rod inside a section of waveguide, which is terminated by a short circuit. The rod protrudes from the waveguide, via a small hole, and is placed against the masonry to be drilled. The rod is rapidly heated by the currents that flow across the surface of the tungsten, and in addition, plasma is generated by the electric field which develops between the tip of the rod and the brick face. The temperatures achieved allow the rod to be pushed into the brick, displacing molten vitreous material. The main advantage of this technique over conventional drilling is that it is very quiet and produces no dust.