A method for generating a variable flow of melted material is disclosed. The method includes providing first and second members having a potential energy difference between them. One or more members is extended at a first average extension rate for a first period while producing an electrical arc. One or more members is extended at a second average extension rate for a second period while producing an electrical arc. One or more members is extended at a third average extension rate for a third period while producing an electrical arc. A transport medium is flowed across one or more members during one or more of the extending steps.