A method of closing off a mold plug opening in a turbine component includes the steps of inserting a weld member into an opening to be closed, and to abut a necked portion within a passage leading from the opening. Heat is applied to the weld member, such that a surface of the weld member in contact with the necked portion liquefies, and such that the weld member adheres to the necked portion, closing off the opening. The weld member and application of heat are selected such that the entirety of the weld member does not liquefy, but remains in the opening, without ever having liquefied. A turbine component formed by the method is also disclosed.