Scale prevention during heat treating Brownells makes a product called PBC. Terry Primos had a tutorial on his website showing how to use it, but it looks like he no longer has a site, so here it goes:
Heat the blade up to ~400F (straw yellow) and sprinkle the powder on the blade (heavily). It'll melt and cover the blade. There are fumes produced by this, so do it in a well ventilated area (your forge whould be in the same area anyway!) Put the blade back in the forge and bring it up to critical. Quench it as normal in whatever you use. After it's cooled put it in warm water and the PBC will come right off - you may have to use a scotch bright pad or a paper towel, but it comes off clean.
Larry's suggestion of wire brushing during forging is a good one. Another easy way to keep the scale from staying on the blade (and being pounded into the blade while forging) is to wet forge. This is the Japanese method. Keep the face of the anvil wet and keep a bucket of water next to the anvil to dip your hammer in. There won't be enough water to cool the blade down, but the little bit of steam that's generated blows the scale off the blade and anvil
very nicely
If you want to try the PBC, I have a can of it I'm not using. It works well, but I typically leave enough sacrificial steel on a blade to grind out any scale that's left after heat treating. My blades are all ground clean before heat treating anyway and b/c of my setup there's not a lot of scale that's produced.
Topic: Removing scale??? (Read 909 times)
