The present invention provides an airbag inflator assembled, in part, using ultrasonic welding. The inflator includes a housing adapted to receive an initiator assembly and an adaptor socket to connect the inflator to the electronic systems of the vehicle. The initiator and the adaptor socket are welded together at a point of interface through the housing of the inflator using an ultrasound welding process. Joint seals are provided that allow the production of a gas-tight seal upon completion of assembly of the airbag inflator.