Hi Wes,

I use an anti-scale on every blade and normally only grind fine enough before H/T to eliminate any stresses at the grinding marks but will grind finer on the ricasso area so as to only need some hand sanding there after H/T as I don't want to take off any more material around the maker's mark there necessary. The anti-scale doesn't allow you to grind any thinner at the cutting edge before H/T as you still need enough material there to avoid warping. As far as the shoulder at the back of the ricasso goes, I always establish it before H/T.

Gary

Thanks Gary, makes alot of sense, appreciate the advise. Wes

I tried using anti-scale a long time ago, and never had much success with it. Of course I might not have been using it correctly...but for me I would harden, and every time I'd use it, I would get deep pitting all over the blade(s) during tempering. It caused me more work then it saved, and I gave up on it.

Personally, when I started using a salt tank, that is what has saved me more time and effort in relationship to finishing then anything. With the salt tank I've experimented, taking blades to completely finish ground, and then heat treated them.....because the liquid salt seals out the air, after tempering all I have to do is a mild hand sanding, basically just removing the tempering oxides, finishing it to the desired finish, and the blade is done. Not that I do it that way with every blade, but it does seem to work very well for folders, and smaller hunting/utility blades.

Hi Ed, I've been doing some reading on the molten salts and would really like to give them a try but the cost is a real factor in setting up it looks like. It would be much easier to use the salts for the hardening and be able to turn right around and have the tempering oven all setup for an immediate temper cycle.

I use anti scale on kiln/oven heat treats ... it helps but not enough to go fully to shape, I still get spots of decarb that need to be removed.When I heat treat in the salt pot I go much closer to final thickness. (I use that mostly for swords) For thin cross section knives like chefs knives I get less warping with a slow heat up in the oven but need to leave them thicker than I would like due to the decarb. I have been thinking of setting up a oven with a noble gas purge, either argon of nitrogen, to get rid of this issue.

MP

Wes,

There are two types of anti-scale available. One is powder and the other liquid. If you decide to use one of them I would recommend the liquid which is available from Brownell's (ATP-641). It's water based and easily thinned or cleaned up.

Gary

I'll look into that soon Gary, but I've already obtained a pound of the powdered PBC and I'll do some trials with it. I'm going to see if it will help with a little occurrence I'm having on a regular basis with my 52100 blades. I preheat my blades in an oven and then use a torch to bring them up to above critical before quenching and when I hand sand at 320 grit I get a swirling grain appearance much like a really faded damascus pattern directly behind the point reaching all the way back to the ricasso. Waxing or polishing the blade will cover it over and make it disappear, but if you bare sand it again it is still there in the metal. It's almost impossible to photogragh.

I've used the ATP-641 and had problems with pitting, as others have mentioned. Maybe I'm not using it correctly. Would be interested to hear the method used by others who have had good luck with it.

I use PBC for heat treating gun-lock parts. Bruce Bump told me about PBC. It is awesome for protecting delicate parts. I heat the parts in my kiln, to 500 degrees. Then sprinkle the parts with the PBS powder. You can also just dip the parts in the powder. I'm sure that I use too much powder sometimes. The PBC will thin out as the part is heated and run off the part in the kiln. Makes kind of a mess in the kiln, but the excess PBC runs off the part, so the heat treating is not hindered by the over application of PBC.

I'm sure that PBC would do a great job of protecting guard shoulders that are cut before heat treat. Although, I have often cut guard shoulders before heat treat and have had no problems with scaling damaging them.

I have installed argon injection on my kiln. Paragon sells an argon injection kit that you can install yourself. This kit comes with one injection port, to be installed on one side of your kiln. It works pretty well, but I am thinking about adding another port to the other side of my kiln. Seems that the side of the blade opposite of the one injection port isn't protected quite as well.