Thread: RSO # 1

If you use the pipe-in-forge method, put a couple small chunks of charcoal down inside (not interfere with room for the blade etc.). It will consume whatever oxygen is in there and give you a reducing atmosphere and a lot less scaling. Or you could simply give the LP a little more fuel and have the same thing. Either way you'll get some scale to remove just a lot less.

I can find a piece of pipe that will stick through both sides of the forge but I will have to check on accessibility to the razor before I fire it up. I should be taking notes on all this. Then again I am pulling the trigger on a small oven this week and I will have notes right in the Rampmaster controller. Should be able to store original recipe I use and program 11 more with the changes I want to make without losing the original. I have a great toaster oven for immediate tempering after. Thought I remembered Charlie saying something about that in 1 of his Vids.

Originally Posted by 10Pups

I have a great toaster oven for immediate tempering after. Thought I remembered Charlie saying something about that in 1 of his Vids.

Once Charlie has his toaster oven calibrated to a thermometer he never touches the controls and turns it on and off by plugging and unplugging it.

Regardless of how you heat things up, i would recommend grabbing some PCB anti-scale compound. I like the liquid variety better. As for the toaster oven, you could use that for a lower temperature "snap temper" but if you are going to have a real heat treat oven, i would let it cool down and use it for the tempering process too.

Anti scale compound is basically useless for razors because you cannot grind the hollows to size anyway. You have to leave about 1/16 for successful heat treatment. Otherwise you risk warping the razor and if the edge doesn't have any thermal mass, it will cool down before you're able to quench it. This means that you are going to have to do more grinding post HT, in which case the formation of scale becomes a moot point.

First make razors, then recommendations; not the other way around.

So does that mean that Mr. Blue's equally inexpensive suggestion of putting some charcoal in the muffle pipe to try to avoid an oxidizing atmosphere is also a useless suggestion? A jar of ATP641 anti-scale cost $15 from Brownells and will last a hobby maker perhaps as long as a year or more. Seems like a small investment to me. I was responding to the post where the gentlemen said that he was in the process of acquiring a heat treat oven with a digital controller so discussion regarding ways to reduce the occurrence of decarburization in the austenizing process seem mildly relevant regardless of what the final form of the blade will be, especially if he now has the capability to give the steel the manufacturer recommended soak for O1.
As for the minimum thickness of 1/16, was that a typo because that is .0625 inches or almost 1.6 millimeters, even thicker than the old adage of "leave it as thick as a dime" suggests. If you ask the professional heat treaters over here like Peters what the minimum thickness should be, they tell you to not grind any thinner than around .015 or .4 millimeter to avoid the possibility of "rippling" warpage at the edge. That comes directly from their website, not from me. .

Originally Posted by Bruno

Anti scale compound is basically useless for razors because you cannot grind the hollows to size anyway. You have to leave about 1/16 for successful heat treatment. Otherwise you risk warping the razor and if the edge doesn't have any thermal mass, it will cool down before you're able to quench it. This means that you are going to have to do more grinding post HT, in which case the formation of scale becomes a moot point.

First make razors, then recommendations; not the other way around.

You get a few too thin and they potato chip...you won't do it any time soon again. Sometimes you can make a 8/8 potato chip down to a 6/8 useable blade, sometimes you can't.

Okay, I now have a new term in my smithing dictionary. "potato chipping." I will put that right next to "corkscrewing" which describes what a thin kitchen knife blade can do. I guess that i have been fortunate in that that the time I starting grinding my edges thin before heat treatment, I had an oven and had started doing the sub-critical stress relief cycle after grinding. That pretty much eliminated any warping even in thinner blades. Still had a dreaded "ping" or two with some thin blades though but those were my fault.

Originally Posted by shooter74743

You get a few too thin and they potato chip...you won't do it any time soon again. Sometimes you can make a 8/8 potato chip down to a 6/8 useable blade, sometimes you can't.

Soooo, a Co2 bottle and regulator dropped in my lap today. I also have argon but that would be an expensive way to go. I think there is a fitting already incorporated into the oven.
I do have some refractory clay just for covering the edge but I think this blade is going to be okay. It's still thick.

I remember Charlie put the blade from the oven to the toaster because the oven was to hot and he wanted to temper immediately? Now I am brain dead as to what part of the process he was working on but that's what I love about videos :<0) I can go back.


Oh, and you can potato chip a blade with a Dremmel too. The thought scares me.

Originally Posted by 10Pups

Soooo, a Co2 bottle and regulator dropped in my lap today. I also have argon but that would be an expensive way to go. I think there is a fitting already incorporated into the oven. I do have some refractory clay just for covering the edge but I think this blade is going to be okay. It's still thick. ...

Whether you displace the oxygen with an inert or reducing atmosphere, or burn it off or use a barrier, you are preventing scale formation. That means less work grinding to finish and having good steel, not decarburized steel at the surface.

Leaving the edge thick gives you some wiggle room to keep the edge straight in case there is a little warp. Grind barehanded and cool in water often. I am a firm believer in thermal cycling to reduce the chance of warping in the first place but a lot of makers don't see that process the same way. I'd rather prevent making a mistake than trying to correct it afterward. Others learn differently.

Heat retention also works for me especially in the time to quench for steels like O-1 and thin cross sections like razors. Clays can offer just enough time to make a difference.

Each of these variables requires time to learn. They are all built on simple foundational principles that are best practiced before moving on to concepts that are more complicated. It's the only way to develop the confidence that each of us needs so we can rely on ourselves to get the job done, in our own shops, amongst the tools we own to get the job done. For beginning makers, I advocate keeping things simple, and encouraging them to use them to make things with their set of tools, not mine or any other makers, unless I know that maker uses the same tool set as the beginner. It breeds more successes than failures from trying to make someone else's process work in a shop that does not have tools appropriate to that process. I lot blades need to be made to collect the data to know what works in this shop or that. 10Pups is working on a couple blades and deserves encouragement not confusion.