hello jefferson, put the capillary in a 1/4 copper tube and weld it normal with a silver rod, then buy a special chalk is like an epoxy paste when it is finished with the fire and dries very fast, because you join the copper tube with the aluminum one you make a bell and you put said chalk glue to the tube that enters (to the male). . . pending you are heating and semi rotating the tube so that no pores remain.