According to the present application, a cartridge system (35) for a cartridge type soldering iron has a sleeve stopper (1) with hooks (24) and a sleeve (21) which goes over the stopper (1). The hooks (24) of the sleeve stopper (1) lock with a socket assembly (70) of the soldering iron which connects to an electrical source. A tip cartridge (35) of the soldering iron has a tip retaining mechanism (37) to fix the sleeve stopper (1) with respect to the tip cartridge (35). The sleeve (1) is made from a non-heat conducting material to protect a user's fingers from heat.