7. Audio Vacuum Tubes, Light Bars, Wood Model Aircraft, Metal Snare Drums

Delicate electrodes and control grids are assembled inside glass envelopes that are evacuated and sealed to form audio vacuum tubes. Optical modules, wiring and housings are combined into emergency light bars; lightweight wooden pieces are cut and joined into model aircraft; and formed metal shells are fitted with heads, tensioning hardware and snare wires to create snare drums.