A pre-press tube is composed of several lengths of tube with a plug-in end at one end and a plug-in socket at the other opposite end. Plug-in end and plug-in socket are chosen to be conical in such a way, that when the plug-in end is pressed into the plug-in socket, not only a form - and force locking arrangement is obtained, but even a tight connection of the material by means of a lattice like polymerization of the contact surfaces is obtained. As a result a tight, solid connection of tubes with a smooth surface is achieved.