Tin foil hat radio with a metal bucket. The AM radio is completely inside a metal enclosure. This leads to a noticeable reduction in signal strength received by the AM radio. The efficiency of a metal enclosure in blocking electromagnetic radiation depends on the thickness of the foil, as dictated by the "skin depth" of the conductor for a particular wave frequency range of the radiation. For half-millimetre-thick aluminum foil, radiation above about 20 kHz (i.e., including both AM and FM bands) would be partially blocked, although aluminum foil is not sold in this thickness, so numerous layers of foil would be required
Foil stamping There are two primary types of foil stamping machines. The first type is manual and the second is pneumatic (air powered), which typically used in a commercial print shop. Manual foil stampers are ideal for low jobs and the pneumatic is ideal for medium to high-volume jobs. Commercial Foil Stamping is usually produced on a Kluge foil stamp press or a Heidelberg Windmill retro fitted for foil stamping. Foils come in a wide selection of colors and finishes, from the most commonly used metallic gold and silver to foils with pearlescent and holographic effects. Foil stamping Foil stamping, (also known