When sanding blade for finish, do you sand then heat treat or vise versa. I tried hand sanding prior to heat treat and am getting no where fast. Then took the suggestion of a friend to use an orbital sander...... way bad idea. I severely messed up what I had already done. May have screwed the whole knife up as I had to put it back in the jig I made and that is extremely hard to get it back exactly where it was in the jig initially. It also thinned the blade more than I wanted. It will probably crack when heat treated now (I hope not).

RD

I wasn't clear with my post. I think the better question is to what degree do you finish (grit size) before heat treat?

I polish out the file marks with emery cloth (240 grit I think). I don't get too crazy because of the scale that usually forms when I heat treat.

240 is a good finish before heat treat. I use a protective product called Turco that limits scale damage during heat treat. ou can find it b googling. It is not cheap.

I have used boric acid as an anti-scale for heat treating. Make an alcohol-boric solution, paint it on, and let the alcohol evaporate. The resulting boric coating is somewhat fragile, so treat it gently until the boric melts in the forge. I was pleased with the results, although I've only used it a couple times. Boric acid starts to attack steel around 1600 F, so it wouldn't be any good for high alloy tool steels or stainless steels that harden well above that temp.