Gun
Gun turns up in 2 fields: thermal spray, geosynthetics. Here is what it means to the people in each one.
Gun in thermal spray
Booth word for the thermal spray torch itself, whether plasma, HVOF, arc or flame.
Everyday name for the device that heats and propels the feedstock: a plasma gun with its electrode and nozzle, an HVOF gun with combustion chamber and barrel, an arc gun with its wire feed and air cap. Sprayers talk about the gun running hot or cold, rebuilding the gun, and gun hours since the last hardware change. Most production guns ride on a robot or traverse unit rather than in a hand.
"Gun's at 40 hours on this nozzle, let's rebuild it before we start the carbide lot."
Gun in geosynthetics
Installer slang for the hand-held extrusion welder used on patches, boots and detail welds.
The gun melts welding rod or pellets in a small extruder, preheats the sheet with a hot-air nozzle and pushes out a bead through a shaped shoe. Barrel and preheat temperatures are set on a trial weld, and the gun is purged before each weld so degraded material does not end up in the seam. Running the gun cleanly around a vertical pipe boot is the mark of an experienced seamer.
"Gun wasn't purged, the first six inches of bead are brown, cut it out and start again."