Flash Control (I.D. Bead Scarfer), When a tube is welded via High-Frequency Induction (HFI), molten metal is squeezed toward both the inside and outside of the tube. While the outside bead is easily removed, "Flash Control" refers to the specialized internal tools (I.D. Scarfers) used to remove the internal weld bead while the metal is still hot. This is vital for tubes that will eventually carry fluids, house electrical wiring, or require a precise internal diameter for telescoping applications.