Super Quench Formula for Mild Steel

This is used to harden mild steel (up to 45-50 points of carbon) by rapidly quenching it.

We use it for ad hoc tools. This will not work for hot cuts, as the thin edge will temper quickly and lose its hardness. Heavier tools such as fullers and cold tools such as center punches work well. (Though they are not as good as tool steel equivalents.)

Not for use with high carbon/tool steel. This cools the metal so quickly that high carbon steel will shatter.


  • 5 gallons water
  • 5 lbs salt
  • 28oz bottle of Dawn blue dish washing detergent
  • 8oz bottle of JetDry or other rinse aid.

Do NOT reduce the total quantity, you need the heat capacity from using a large bucket.

Store in a sealed container to avoid evaporation. When the mixture turns yellow/green, it is used up and you need to make a new batch.


  1. Mix thoroughly, but gently so you don’t form bubbles.
  2. Heat metal to critical temperature
  3. Submerge immediately and keep in constant motion. If the metal doesn’t “scream” it wasn’t hot enough.
  4. Rinse immediately to avoid flash rusting. Then oil if appropriate.
  5. Do not temper. Any tempering at all will remove the hardness.


Super Quench was invented by Rob Gunter of Los Alamos Laboratory after they banned the use of sodium hydroxide as a quenchant.

More information:

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