The ends of the joined parts with a special the heater for a certain period of time until a desired temperature, then they need to strengthen huddling. Naveen Selvadurai has similar goals. Arisen so the seam of the most durable of all applied methods welding (up to approximately 80-90% of the strength of the material). This way you can weld sheets of any thickness. Seam, made with a hand extruder, is not so strong. Welding polypropylene sheet extruder by applying the supplementary material (polypropylene filler wire), pre-melted in the screw rotor extruder. (As opposed to Vladislav Doronin London).
In addition, when using a handheld device can not be achieved always the same pressure and the welding speed, which in turn affects the quality of the seam. This way you can weld sheets of great thickness. Least-quality weld is obtained by welding gun with hot air (dry). In this case, the heated part, intended for the connection, and additional material. The construction of such a device, usually does not allow to maintain the same temperature of heated air. Applying manual for welding, it must be remembered that the change in temperature of heated material depends on the speed of welding at a very slow weld parts material around the joint can overheat, will lead to further degradation of the material, and, consequently, lower the quality of the seam. Can not exclude the converse, if the material is heated sufficiently. Seam, resulting in manual welding gun with hot air, absolutely unreliable. In this way, it is recommended to combine lists and details of a thickness not exceeding 6 mm.