Method of forming pipe union

A method of joining two standard pipes originally having identical dimensions and walls which are comparatively thin relative to their diameter, wherein the pipes have previously been subjected to the steps of forcefully socket jointing the end of one of the pipes within the end of the other over a length which is at least equal to its diameter, while gripping the end of the other pipe in an undeformable die over the socket jointing length, separating by traction the jointed ends whereby the two ends interfit one within the other except for differences in diameter due to elastic retraction upon separation, subsequently rejoining the two ends over the initial socket jointing length by insertion of one end into the other and applying a socket jointing force of short duration to overcome the difference in the diameter of the two ends due to the elastic retraction.