Will I have been admiring your work for a very long time, and this is one of the most exciting things I am looking forward to. Thanks so much!
Thanks Don you are a gent, your enthusiasm is most welcome
I'm excited about making a hamon on it. I have not done much with shallow hardening steels before so that will be a new thing, though i've made hamon by accident before in W2 damascus.
From my reading, grinding the bevels at least some of the way before the quench will help the hamon as just the edge being thinner and the spine thicker will make different hardness's, assuming the steel behaves as a shallow hardening one.( I would normally taper but not grind the bevels until after HT) I will clay it up of course, I'm going for a warm water quench, in the bosh on the back of my coke forge.
Any last words or advise?......
Thanks for posting the videos. I am absolutely fascinated by your process. Looking forward to seeing how it comes out.
This is fascinating. Is there any more progress?
Annoyingly, it did not harden, well not fully in any case. There are quite a few things which could have gone wrong but I have a feeling the iron needed a longer soak and after all the folding there was not anywhere near as much carbon as I predicted. I will be trying again with just pure iron as using both mild steel and iron in this batch made it even trickier to work out what went wrong. Ah well we live and learn...
The school of hard knocks is a very expensive way to get an education. Sorry this happened. Thanks for doing this for all of us. I heard once that charred bone works best for carburizing. Good luck.
Love and respect
Yep, a bit more magic in the compound I think....and a longer soak. The wrought had distinct blisters on the surface, the mild, none, though both spark tested on the surface showing carbon, perhaps the iron can take the carbon more readily, I was worried about using the mild steel because of unknown quantities of alloys....
So it will be a bit more controlled next time with the pure iron, which I will know the specific chemistry.
For those wondering the difference between wrought and pure iron. Wrought is the "old stuff" Smelted from ore, worked in a bloom, then rolled and re-rolled to a specific grade. So wrought iron is all very old as it is not actually made in any quantity any more, though it is collected and re-rolled.
Pure iron is a modern product. I presume a crucible melt with alloys and impurities added to approximate a sample of wrought iron, then rolled to product. So it wont have the strand type grain of old iron as it has not been refined by rolling and re- rolling. Its more uniform. So could be a better bet for this type of experiment.
Here is what is in it, which you may also find in a sample of well preserved wrought, though they are very different materials to work with.
Thanks Hoss for spurring me on, I will try again one weekend soon
I tried making blister/sheer steel last fall and took a bunch of pics for a potential wip and mine ended with the same result of yours. I only cooked it in the forge for a few hours and did not get the carbon penetration needed to harden. I read a recent wip where the maker put the iron in a wood stove to carburize for upward of 12 hours. Rick Furrer (sp?) on Don Foggs forum has done classes here in Maine on how to do this, but I missed it. Good Luck.
Originally Posted by WillC
Hi, Will. I am a new comer to the forum here.
I have admired your work for quite some time now. The knives you made are just exceptional! And there's nothing more exciting than checking your new work on this board every other week.
Alright, let's get back to our subject... blister steel
On your experiment... from the cut-open BLUE colored blister steel picture you took, I think, it probably gave a hint on why the quenching failed at the end (not enough carbon). The blue color might not be the right one your are looking for, and it should have been pink or yellow color. I could be wrong on this... but, doing some reading on Japanese Kera (steel bloom from Tatara Smelting) color could possibly point you to the right direction. Please take a look at the google books link attached at the end of my post, the book title is "The Art of the Japanese Sword" (only sample pages are available, but it's already good enough), pay attention to the section that describes the 5 different colored regions of Kera,
1. Yellow, Tamahagane, carbon 0.5 - 1.2;
2. Pink, Owarishita, carbon 0.2 - 1.0;
3. Blue, Hobo, mixture of Tamahagane and IRON;
4. Grey, Noro, mixture of slag, steel, iron, and impurities
5. Green, pig iron, carbon 1.7 and above;
In later pages, there's also a close-up picture of 3 good Tamahagane pieces taken from a Kera, it demonstrated a lot of the yellow color and some pink and blue spots.
Other than the coloring, like you suspected... the iron pieces used in the experiment might have been just too thick and the soaking time was not long enough.
In addition, besides the blister steel method, there are also other ways to carburize iron to steel. In contrary to the common believe of Tamahagane must be obtain from Tatara smelting, Japanese from ancient times actually made small quantity of it directly from a smith forge by melting and carburizing salvaged iron objects... The book I linked has this info also. In the later pages, there's a section explains "Making Tamahagane in the Forge". Maybe it will give you some new ideas (with less trouble)?
Thanks for that Mr Clinton, it was rather puzzling why the piece would not harden. Looking back on this I think it was actually a heat treatment problem. As the piece sparked well, showing carbon and diffusion should have been complete after all the folds. I think I did too many heat cycles on the piece and it would not harden. As I'm used to oil hardening steels. Having done a bit more recently with water quench steels I think this could have been the case. I think the next experiment of this nature will be a smelt under the guidance of a friend who has much experience of making steel. Thanks again for your comments