Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area and electrode are protected from oxidation or other atmospheric contamination by an inert shielding gas (argon or helium). A filler metal is normally used, though some welds, known as autogenous welds, or fusion welds do not require it. When helium is used, this is known as heliarc welding. A constant-current welding power supply produces electrical energy, which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma. GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminum, magnesium, and copper alloys. The process grants the operator greater control over the weld than competing processes such as shielded metal arc welding and gas metal arc welding, allowing for stronger, higher quality welds. However, GTAW is comparatively more complex and difficult to master, and furthermore, it is significantly slower than most other welding techniques. A related process, plasma arc welding, uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.
Glossop is a market town in the High Peak, Derbyshire, England, 12 miles (19 km) east of Manchester, 24 miles (39 km) northwest of Sheffield and 32 miles (51 km) north of the county town, Matlock, near Derbyshire's borders with Cheshire, Greater Manchester, South Yorkshire and West Yorkshire. It is between 150 and 300 metres (492 and 984 ft) above mean sea level, and lies just outside the Peak District National Park.
Historically, the name Glossop refers to the small hamlet that gave its name to an ancient parish recorded in the Domesday Book of 1086, and then the manor given by William I of England to William Peverel. A municipal borough was created in 1866, and the unparished urban area within two local government wards. The area now known as Glossop approximates to the villages that used to be called Glossopdale, on the lands of the Duke of Norfolk. Originally a centre of wool processing, Glossop rapidly expanded in the late 18th century when it specialised in the production and printing of calico, a coarse cotton, and became a mill town with many chapels and churches, its fortunes tied to the cotton industry.
Architecturally, the area is dominated by buildings constructed of the local sandstone. There remain two significant former cotton mills and the Dinting railway viaduct. Glossop has transport links to Manchester, making the area popular for commuters.