[jimmontg]

For me and the cryo it's a bit different. I have forged knives, but I don't anymore. I make kit knives and it will be marked as a wildcat skinner blade from TKS with cryo. With the blades that are treated that way, especially 440c, it makes a difference. When I made knives out of D2 at work they benefited from a soak under dry ice. But NO acetone! Use diesel fuel or kerosene if you must use a liquid. I just put the knives between two pieces of dry ice and left them over 24 hours. I make my own blades too, but if I see a premade blade I like I will buy it. Alex at Texas Knifemakers Supply will Rc any blades that you buy from them if requested. They also are quite affordable for HT, but they do not do any oil quench steels.

I was taught that you can temper your blades back a Rc point or two and the cryo would bring it back about a point, but it will be a more flexible blade. My son's filet knife was D2 and it was Rc 59.7 after cryo with dry ice, but it was as flexible as at the double tempered 57.8 Rc. Now whether that is true or not I cannot say for sure, but it is what I was taught back in the 90's. It will help the blade to retain flexibility while maintaining edge holding as well. Also the cryo wasn't helpful for alloys that didn't have much chromium or vanadium. I asked once if cryo would help with O1 as I never cryo'd it as it has such a small percentage of chrome at 0.5%, but I've been wondering about it as it has vanadium and tungsten as well. Does anyone else know about this?

Oh and completely off topic if you have tried to bend either aluminum or brass extrusions and they cracked the solution is simple. Take a torch, any kind is suitable if it can bring the metal up to about 500 degrees F in the area to be bent. I always used a piece of pine and rubbed it on the metal until it started to burn it. You then have about 2 to 4 hours to bend the extrusion, after that time it will revert back to it's same brittleness. I used to make hand rails and some alloys cracked or broke when we put them in the pipe bender. I've bent brass and aluminum bar and it did the same. Hope that helps somebody.