In shop slang, a spelk is a tiny, needle-like splinter of metal or a razor-sharp flake of overspray that penetrates a worker's skin. In thermal spray operations, these hazards typically come from handling frayed twin-wire arc feedstock, sweeping up brittle ceramic overspray, or peeling masking tape that has jagged coating build-up on its edges.
I got a nasty spelk of molybdenum wire stuck in my thumb while feeding the gun.
Always wear heavy leather gloves when stripping masking tape or changing out stiff alloy wires to avoid driving a spelk into your palm.
Related terms
Twin-wire arc
Process that melts two electrically charged wires in an arc and blows the molten metal onto the part with air.
Overspray
Spray material that misses the part or fails to stick, ending up in the collector or on nearby surfaces.
Masking
Covering areas of a part that must not be blasted or coated, using tapes, plugs, shields or maskants.