<p>The apparatus for welding articles of thermoplasts using additional welding material is provided with a special melting device for the welding material. The melting device comprises a guide channel for the supply and preheating of the welding material, which channel merges into a melting channel of diminishing cross section closed at one end. The melting channel is provided with lateral bores which discharge into a melting chamber of low height in communication with a collecting zone for the plasticized welding material, which collecting zone is connected with the outlet opening of the welding shoe.</p>
