To make a mixture for quenching, you will need 5 gallons of water, 5 pounds of salt, 32 ounces of blue Dawn dishwashing liquid (28 ounces if it’s concentrated), and an appropriate amount of a wetting agent like 8 ounces of Shaklee Basic I or 7 ounces of unscented Jet-Dry or another surfactant such as Simple Green. The wetting agent helps to break down the surface tension of water and prevents the formation of a layer of air or oily residues that can act as a heat shield during quenching.
When using a rinse agent like Jet-Dry, it reacts chemically with the steel surface to allow the salt in the mixture to start attacking it immediately after exposure to air. To avoid this, have plenty of clear water ready for rinsing.
Before quenching, stir the mixture to ensure that it is well-mixed. Only quench materials with a maximum of 45-50 points of carbon, as this will harden mild steel to a Rockwell 42-45. The mixture changes color from blue to green when it is no longer effective for quenching.