Abstract: An apparatus for welding a workpiece comprises a body tube having a tapered portion defining a first angle, and an end fitting releasably connectable with the body tube and having a tapered portion defining a second angle. The tapered portion of the body tube is releasably connectable with the tapered portion of the end fitting. The first angle differs from the second angle by a distance sufficient for facilitating manual separation of the tapered portion of the body tube from the tapered portion of the end fitting. A liner has a first portion disposed within the end fitting and a second portion disposed within the body tube. A connection member operatively releasably connects the first portion of the liner with the second portion of the liner. A member is disposed on the body tube or the end fitting for releasably connecting the body tube to the end fitting. A positive stop member is formed the body tube or the end fitting for positively retaining the member on the body tube or the end fitting.