This process involves stacking alternating layers of steel and copper, then heating and pressing them together in a manner similar to forge welding. Because copper melts at a much lower temperature than steel, the process relies on a brazing action where the copper bonds to the solid steel. Knifemakers use it to produce striking, contrasting lines in the finished blade after grinding and etching.
Watch your temperature control when you forge that cumai billet, or you'll melt the copper right out of the stack.
The stack must be heated just enough to allow the copper to flow and bond without turning into a liquid puddle that squeezes out under the hammer.
Also heard as
- Cu-Mai
Related terms
Brazing
Joining metals with a filler melting above 450 °C but below the base metals, drawn in by capillary action.
Base metal
The primary material or workpiece being joined or cut during a welding operation.
Braze welding
Laying a bronze filler in a groove or fillet like a weld bead, without relying on capillary action.