Whether the steel strikes the flint or the flint strikes the steel, the sparks that are created are actually micro particles of the carbon rich steel that are “red hot” when shredded off by the percussion of striking.

In today’s modern world there are materials that are very hard that can be used instead of traditional flint. These are usually found in the form of ceramics. A common source is broken sinks or toilets that are often referred to as “john stone” or “thunder stone”. Another source is broken Corning® Dinnerware or Bakeware. These materials can be acquired in an urban environment and are occasionally used by flint knappers to hone their skills.

This alternative source was the case for me as I was assembling a DIY flint & steel kit for a friend recently. As I searched my basement for all of the kit’s components, I couldn’t find a suitable stone. I passed by my flint knapping area and noticed some Corning® pieces where I had been working on an arrowhead. I picked up a piece to test it for sparks and “presto!” it worked great! It dawned on me that I no longer had to rely on rocks for a flint to make a functional kit.

Esthetically a rock is more traditional to flint & steel firecraft but now I know that alternative materials can be used to make a fire when needed.

Basically, all you have to do is turn an empty ceramic coffee cup upside-down and place it on a table top. Most cups are glazed only on the upper portions and perhaps a recessed bottom, but there is usually a bare ceramic ring exposed that provides just the right abrasion for your blade. My Spyderco Endura has some pretty tough AUS-6 stainless steel that takes a bit of effort to sharpen, but carbon steel blades work quickly. Of course a crowning final touch would be to strop your blade on a hearty pliable surface like a leather belt to set the edge.

I’ve heard that others have used the frosted edge of a car window, or shiny finished cement, but I find that cups have the right abrasion, consistent surface, and can be found quite easily. Just hold the cup by the handle with one hand for stability and with the other hand hold your blade at about a 20 degree slant for a double-sided edge, or at a 40 degree angle for a single single-sided edge.

After your next morning Joe, turn over your cup and give it a try. Just don’t scare the folks around you…