Thread: Black Ice?

I have been working on a stainless blade with my Norton 4k/8k and looking at it periodically under the hand held magnifier (with a light built into it). When I catch the right angle it appears to have a black line all the way down the blade. I was under the impression (can't remember from where) that this was not supposed to be there. I was reading a post on here this monring (can't find that again either) that said this should or could be there and that was normal. Is it? The edge on this thing looks great all the way along the blade and I just havn't moved to finishing it because I have been trying to get this line out. The reference I saw this morning about the "Black Ice" is just what it looks like and according to whom ever made that post this is Ok'y Dok'y?
Donald

Sounds like what you're describing could possibly be a wire edge. A wire edge is formed when a blade is overhoned. The steel at the very edge actually becomes so thin that during the next pass on the hone, it actually folds or curls up and around the edge. When sharpening knives or wood working tools, you actually want this to happen before moving on to the next grit of hone, but such is not the case with razors.

The detect a wire edge, you can either use a microscope to try and see it. Alternatively, you can stroke the pad of your finger from the face of the blade outwards perpendicularily off the edge, and then repeat the process on the other side. You know there's a wire edge when the stroking feels different on your finger from one side of the razor to the other. The wire edge will also tend to grip the ridges on the pad of your finger as well. Takes some practice to feel it, but it can be done.

What may be done to rememdy a wire edge is to run the edge of the razor along a match stick (or something equivilent). This will break off the wire edge allowing for much easier rehoning of the edge. Of course it gets a little more tricky in practice, but that's the jist.

There's also always the possibility that you don't have a wire edge at all and that it could be something else all together

Thats my reference to how the bevel looks to me off angle when I hone on a hyper high grit. If its the entire bevel that looks like that your good to go. Sorry, okey dokey or whatever. If its just a thin line at the end of the bevel (the edge) that could be two things. One, on a sharp blade the edge will show a line sometimes because the edges should connect. I personally don't have any experience witnessing this line though. The other possibility is that it is an overhoned edge. I prefer to deal with this via backhoning on 8K. Some people refer to the overhoned edge as looking more like a dotted line btw.

How does it shave? That should give you lots of information.

Thanks for chiming in on the Black Ice reference. My line is as you say the entire bevel and not just the edge. So I will finish up the job and give it a test. I hadn't tried to shave with it because I was confused about this Black Ice observation. Now that I know I ain't losing my mind I will move forward.
Thanks
Donald

No, its real. Although don't be surprised if no one else ever believes both of us. BTW, if you tilt the razor a little you'll see the striation pattern again. All your seeing is the bevel being smoothed out, which helps in the comfort area.

Originally Posted by AFDavis11

Some people refer to the overhoned edge as looking more like a dotted line btw.

The dotted-line look is a dead giveaway because it means the wire edge has already started tearing away.

The edge and bevel look different depending on how light is hitting them. I use the RadioShack illuminated microscope.

If you look at the bevel so that the light from the microscope is reflecting straight back at you, then you'll see the scratch marks from the hone. But if you look at the bevel from the right angle, the light will reflect away from the microscope and you'll get the "black ice" effect.

I move the microscope around to look at the edge from both of these angles, as you can see different things from each. Viewing the grit lines allows you to see how you're doing in terms of smoothing the bevel. You want to see the fine lines consistently. If you see bigger lines mixed with smaller ones, you probably have more honing to do.

Looking from the "black ice" angle lets you see more easily if the edge is straight. It should be completely straight when viewed at 60X. This view also helps you check for overhoning. If you see black bevel tipped with a bright line, then chances are good you have a wire edge.

Like Alan, I'll do some backhoning strokes, maybe 3 to 5. Then I'll do a few more regular strokes and check it again.

Good luck,
Josh

This forum is pricless to me. If a guy had to learn this stuff through trial and error it would take years. This information is just so essential for this art of straight razor shaving that it is unbelievable. The part that I really like is that us new guys get to ask what must appear to the senior members some really stupid questions and the answers are always polite and civil (well in most cases) . I am sure that I haven't learned enough to stop asking the stupid ones yet so thanks to everyone for putting up with the learning curve.
Donald