<p>A gas burner applies a flame to a workpiece surface and has a case around a void with a gas inlet. The void holds a stack (2.1 to 2.n) of a first type of metal foil and a second metal foil. The first metal foil forms a series of alternating slit outlets (6) for burner gas. Each layer of the first foil alternates with a layer of the second foil.</p>
