Heat treating

[jolson]

I just did my first knife quench. The blade turned black with soot from the canola oil. What is the best / fastest way to clean it up again?

 

[Stang Bladeworks]

Sandblast it

 

[Justin Schmidt]

200grit on the belt grinder

But ive heard of people using vinegar

 

[i4Marc]

Sodium Bisulphate (PH Down - pool chemical)

 

[Grayzer86]

The black layer is basically light scale and burned oil. It should be sanded or ground off. There will also be a layer of decarbed steel under that that should also be ground away. Combined with preventing warp, that’s part of the reason that we leave the blades a bit thicker than final dimensions. It gives us the extra material to be sacrificed as decarb and then ground away.

 

[JTknives]

Elbow grease

 

[Stacy E. Apelt - Bladesmith]

Unless HT is done in a vacuum oven all blades need to be re-sanded after quench.

 

[comet_sharp]

Use brake degreaser to get the oil off. I forge mine to final thickness, normalize and anneal into fine spheroidite. I then do straightening at sub critical temperature until it stops moving and aust/quench. Once again, brake degreaser to clean the oil off. Temper. Soak in vinegar overnight and scotch brite blue belt. You get a very pretty "nashiji" or brut de forge finish. Then grind bevels and be aware the finish is soft decarb above the bevels.

Easy way
Brake degreaser
Sandblast 80 grit abrasive or so

I clean my blades fully when ready for final quench and use a coat of atp

-Trey