A first-timer's attempt at a hamon:
Well, I finally got around to heat treating that top knife. I really wanted to try my hand at clay hardening with this one. I've always seen these pictures of beautiful hamons on 1095 and W2 steels, and I figured, well hell, why not? Worst that could happen is I get an ugly hamon, or no hamon at all.
A generous soul on another forum donated some refractory materials so that I could build a paint can forge, including some satanite cement, and I had a dab left over, so I mixed it up and gave it a whirl.
I globbed some of the satanite on (about 1/8" thick), made a simple wavy pattern, and to the hot paint can forge it went. Heated to orange (at night to see the color well), tested with a magnet, soaked 10 minutes at that temperature, quenched in brine, and then tempered twice at 450 F (one hour for each tempering) until the telltale straw colored oxide formed.
I could see a line as soon as I raked the clay off the blade, but I read that that's not really indicative of a true hamon, as you can get surface decarb on the blade that follows the contour of the clay pattern. So I (reluctantly, and with great apprehension) hit it pretty heavily with some 120 grit, and worked back up to 2000 grit, and then etched in hot apple cider vinegar, and polished with some stainless kitchen sink polish (it was the only liquid abrasive I had handy).
Here's the result:
Not the prettiest hamon I've ever seen (not by a long shot), but I was real pleased just to see one at all. I just knew it would sand right off, so I was happy to see it was actually a true hamon.
So there it is, my first ever attempt at clay hardening. I'd say it's at least a step in the right direction, anyway.
Some things I learned:
Despite what I read on the internet, Radio Shack does not carry ferric chloride. At least not the one near me.
When etching the blade, it helped to get the vinegar
hot. I've read a lot about
warm vinegar, but the boiling point of acetic acid is pretty low, and you will not get the vinegar hot enough to damage a heat treat, so I got the vinegar up to a full boil on the stove top, cut off the heat, and then etched. After several blotchy failed attempts with wiping the vinegar on with paper towels, trying a soak in warm vinegar, and a messy fiasco involving a lemon and a cut finger, I figured out that a full immersion in near-boiling hot vinegar did the trick.
My propane burner (which is the cheapest Bernz-O-Matic LP burner they make) sucked! It was very positional when used with the paint can forge. I finally got it set up at just the right angle, and it would work, but if you touched the thing, I mean if you even breathed on it, it would immediately snuff out. I'd recommend anyone who builds a similar DIY forge to go with a better burner, and not be a cheapskate like me. I hate that old adage about "buy cheap, buy twice," because sometimes there are really good deals out there, but in this case, the adage is true. I'll have to get a better burner.
Propane worked, but it was slow to get the forge up to temp. I will probably try a MAPP type gas next time.
The satanite worked really well for the clay. I've read of people having issues with other types of clay breaking off in the forge, but I didn't have any issues.
Another thing I learned is that the hamon may or may not follow your clay line. On some areas of the blade, it followed the lines perfectly, and in others, it's like it had a mind of its own. I haven't figured out if it's because of temp variations, clay moisture variations, or what, but that's what I observed. Honestly, the areas where it deviated from the line are the most interesting to look at. I wish I could figure out how to recreate that intentionally.
I will be trying this again. If nothing else, I had a lot of fun doing it.
Now for a handle...
Jason