The knife making course I did was through the Learning Connexion, which is a private art school based in Upper Hutt. I ended up doing two courses; the first was three days making a piece of “Damascus Steel”, the second was three days making a knife, using the piece of steel. People could also just do the knife making without the piece of steel, using something from the various bits of spring steel around the studio.
I say “Damascus Steel” in brackets because what we are talking about is actually pattern welded steel, where two types of metal are layered together to create a billet with a wood like grain, that depending on how its worked, can show various patterns. The original Damascus steel was a technique associated with sword making, and was a specific bit of metallurgy associated with a local tradition. The Wikipedia page on Damascus steel gives some indication of the history and complexities of the process.
Anyway, the creation of the billet of steel is a combination of metallurgical knowhow, high temperatures, and beating the crap out of things with large hammers.
Our billets were created using old file blades, which are brittle but very high carbon, and spring steel, which in theory is softer, but more flexible. The idea is that by layering them, and welding them together, you should be able to get the properties of both. I also suspect that in knives, the differing steels would provide a subtle micro serration of the cutting edge, but that is a bit of speculation on my part.
I had presumed that welding the pieces together would be a simple matter of high heat and force, but in fact, the process requires a bit of chemical treatment to ensure there are no impurities that can get in the way of the metal layers welding to one another.
Below are some photos from the billet making course, and a collection of the final billets.