Firstly, I explained the preparation of metals; pile the different colors of metal alternately and bind strongly with the jig that is specially ordered for making mokume-gane. Secondly, I explained the technique of wielding; heat metal with a burner and wield metals watching the condition of metal very carefully.
From here, I explain the process called ”the forging technique”; hammer metal in the color of red heated by flames to make mokume-gane material stronger and thicker after wielding.
The technique is called “forging” or “hammering metal,” the one of the plastic deformation techniques.
By striking and compressing metal with a rather large metal hammer, the void inside of metal is crushed and crystals become minute. Then enhance the strength of metal by adjusting the direction of crystals and mold metal into the intended shape.
Japanese sword is described as “Japanese tradition” that has been made with the technique peculiar to Japan. The major producing technique of Japanese sword is “forging” that has made unique progress in Japan.
By the forging process, raw material with the excellent strength can be made because the structure of metal becomes thick with the progression of metal flow and blowhole rarely appears comparing with the other casting procedures used in the most of ring making.
First of all, remove the jig from mokume-gane metal and heat it with a burner again.
Without the jig, the color of metal changes from red to orange more quickly than previous time. But here, do not heat metal to melt.
Put out the fire before melting and crush mokume-gane material with a hammer at the appropriate moment that temperature of metal begins to drop and the color changes from orange to red.
By repeating this process many times over, stronger and durable metal is made.
At this point, the shape of metal can be changed if it is pulled up with pliers too rapidly. So pull up metal after cooling down very slightly.
Place mokume-gane material on a stock called “an anvil” that is used in forging and crush with a hammer immediately.
After metal becomes cool at room temperature, it is difficult to make the structure thick and to transform metal into the intended shape.
The timing is extremely crucial. The aim is not achieved if the process has been done too rapidly or too slowly.
That is the reason why the forging technique is regarded as difficult.
Because the process is highly dangerous with heat, put on leather gloves and use a rather large pliers That is the whole process of making stronger mokume-gane with high density than normal metal.