What is "blow torch"

n. (alternative spelling of blowtorch English)

A blowtorch (USA usage), or blowlamp (British usage, or rare or archaic), is a fuel-burning tool used for applying flame and heat to various applications, usually metalworking.

Early blowlamps used liquid fuel, carried in a refillable reservoir attached to the lamp. Modern blowtorches are mostly gas-fuelled. Their fuel reservoir is disposable or refillable by exchange. The term "blowlamp" usually refers to liquid-fuelled torches still used in the UK. Liquid-fuelled torches are pressurized by a piston hand pump, while gas torches are self-pressurized by the fuel evaporation.

Fuel torches are available in a vast range of size and output power. The term blowtorch applies to the smaller and lower temperature range of these. Blowtorches are typically a single hand-held unit, with their draught supplied by a natural draught of air. The larger torches may have a heavy fuel reservoir placed on the ground, connected by a hose. This is common for butane- or propane-fuelled gas torches, but also applies to the older, large liquid paraffin (kerosene) torches such as the Wells light.

Many torches now use a hose-supplied gas feed, which is often mains gas. They may also have a forced-air supply, from either an air blower or an oxygen cylinder. Both of these larger and more powerful designs are less commonly described as blowtorches, while the term blowtorch is usually reserved for the smaller and less powerful self-contained torches. The archaic term "blowpipe" is sometimes still used in relation to oxy-acetylene welding torches.