Luka, that's a pretty nice first try! I think what you are seeing is the effect of carbon migration along the weld seam. If you look at it again, you will see a dark area along the edge (high carbon) followed by a lighter area (where the carbon has migrated out of the high carbon) followed by a stark white line (the weld seam) followed by another darker area (where the low carbon steel has "taken" carbon from the High Carbon) followed by another lighter area (low carbon)

The 2-color scheme happens really well when you use stainless as the jacket layers. Even under those conditions, there is usually a fuzzy area along the weld seam from carbon migration. It's just not as obvious as in your case.

The carbon migration does not penetrate all the way through the jacket layer, so when you grind a bevel through the different layers, you get the gradient look.

Thank you for a great answer!

Luka

Yes - the unhardenable jacket can act exactly like clay and create a hamon. I've had it happen many times in 1095.

Stainless San-Mai offers a really dramatic display of carbon migration.

This is just two pieces of steel.

The bright shiny/reflective line is where the carbon deficient stainless "sucked" out the carbon from the carbon rich 1095. So the shiny line is 1095. (It didn't really suck it out - carbon just wants to equalize.)

If the gray area is the carbon migration area, it seems to me the thickness of the carbon piece makes a difference. The thicker it is, the wider the migration band will be? Is that correct? Is there some sort of golden standard of how thick your carbon piece should be for, say, a regular EDC knife? Mine was probably somewhere around 3/32.

|quoted:

If the gray area is the carbon migration area, it seems to me the thickness of the carbon piece makes a difference. The thicker it is, the wider the migration band will be? Is that correct? Is there some sort of golden standard of how thick your carbon piece should be for, say, a regular EDC knife? Mine was probably somewhere around 3/32.

The carbon is only travelling microns of distance. The thickness only has relevance to the proportions of the final display. The thinner the core is in relation to the jacket, the closer to the cutting edge the bottom of the jacket will be. As well as how thin you forge the final dimension.

There are many variables.

I just had a full description of this all written out and lost it during posting. I don't know why.

This is from Kevin Cashen.

Here you can see the carbon rich core steel on the left.

The second zone moving right is where the carbon vacated the core steel to move into the jacket to equalize.

The third zone is where the carbon moved to.

Then the last zone is the raw jacket.

Think of what happens when you grind across these horizontally.