I have used Kasenit on numerous parts with good results. It will put a skin on a piece of low carbon steel that a file will just "Skate" across. When you put the red hot part down in the Kasenit it will cool down & requires being brought back up to heat prior to quenching. Were you skipping this step Kurt. To harden any piece of steel either by case hardening or by through hardening on higher carbon steel it is requisite that the steel be above its critical temperture at time of quench. If you have cooked in the carbon & quench from this temp, it should harden.
