Fusing laser toner to metal:
Holding the brass plate about 1/4-inch from the hot coils with long-nosed
pliers, keeping it moving so the heat is distributed evenly and watch
closely as the black laser toner turns from a dry look to a satin look.
Don't overdo it! If you hold it too long, or touch the metal to the coil,
it will turn to dust and not be effective to resist the etchant in the next
steps - etching the metal in ferric chloride. via GIPHY