Some of the refractory cement was being very stubborn in coming off the steel, and the file was all I had to do it. Unfortunately, it bit too deeply since it's still a fairly fresh file. It's not a big deal, though. This knife was something of a throw-away.
After the tempering, I went at it with 80 grit sandpaper for a while. As you can see, the bevel on the edge isn't particularly good. This was something I was struggling with during the initial grind. I have no real intention of fixing now, either.
Here I've been using the same piece of 80 grit sandpaper for too long. The result is that it's become something of a higher grit, resulting in more of a polishing action than scratch and scale removal. It still looks like a regular piece of steel, at this point.
I bathed the steel in a mixutre of vinegar, lemon juice, and salt that I'd microwaved for approximately two minutes. This etched the steel, and let the pattern from the refractory cement appear. After the bath, I gave it a quick rubdown with a used piece of 80 grit. The result is evident, but not particularly striking.
I returned it to the bath for about 15 minutes, this time. Once I pulled it, I gave it a good rub with 1,200 grit sandpaper. Now, usually the etch comes last, after moving through 80, 120, 220, 400, 600, 800, and then 1,000 grit sandpaper. However I'm a lazy ass and this knife is more of an experiment.
Anyway, the etch is quite visible now. In the right light and angle, it's a very striking image. It's spackled, not at all what I'd originally imagined. However, I'm fairly confident I know why this happened, and I should be able to counteract this next time.
Now, there's a reason the pattern on the blade looks speckled. I didn't wait nearly long enough for the refractory cement to dry out. This meant there was still moisture in it, and during the firing of the blade, that moisture turned into steam and bubbled up. This pulled the cement away from the steel, creating the look seen here.