PURPOSE: To elevate the production efficiency as well as to make a scroll lightweight by combining the lap extruded continuously and the mirror plate forming a rap groove in advance with the solder having the main component of Al, Zn of the specified weight %.

CONSTITUTION: A continuous rap 8 is obtd. with extruding by a die 3 after heating uniformly the extruding billet 7 of Al alloy. etc. A one piece part of the rap 10 is then obtd. with cutting the rap 8 by a cutter 9. The mirror plate 11 which is formed with press work or powder molding has the groove 12 for the rap positioning. The rap 10 is combined with the solder having the main component of 50W55% Al and 45W50% Zn, after inserting into the groove 12. Due to the scroll being lightweight and the rap part being formed with extrusion with this method the production efficiency is elevated.