Cleaning up slag

[jolson]

I just oil quenched a few file knives I recently made and now they are all blackened. What is the best way to clean them up and get all the black stain off of them and shine them up again for final finishing, sanding, wire wheel on bench grinder, or buffing wheel?? Not sure which is the most effective and efficient way to go, or maybe there's a better way?

 

[Bill DeShivs]

Soak them in warm vinegar for a few hours.

 

[Stacy E. Apelt - Bladesmith]

You Have scale, not slag. Scale is oxidized metal, slag is hardened flux/metal/minerals from melting things.
Soak the blade in vinegar overnight, or in FC for an hour, then scrub it with a stiff brush and dish soap. That will remove the scale good enough to go to finish sanding/grinding.

Some chaps use muriatic acid and soak the blade for 5 to 10 minutes. That does it well, too. Muriatic is far more dangerous, so most folks use vinegar.

 

[jolson]

Thanks. What is "FC"?

 

[Hengelo_77]

Ferric Chloride
FeCl3

 

[Maelstrom78]

I just grind it off. Rough on belts but that's how I roll! If you have a high carbon steel ( which I am assuming is the case ) you will have to finish grind it anyway to get through the decarburization.

 

[JTknives]

I wash it and toss it in the abrasive tumbler over night.