Purge plugs seal pipes to create an area around a weld to contain purge gas. Plugs have a quick-connect attachment to introduce gas through the plug. They are generally used on short runs of smaller diameter pipes than purge paper and bladders. Seals on these plugs ensure a tight fit. Pipe purging is done before TIG welding stainless steel, aluminum, and other corrosion-resistant materials to prevent oxidation that can negatively affect appearance and the material's corrosion resistance.