Mokume-gane– How It’s Done (Soldering Technique)
Traditionally, Mokume-gane, i.e. lamination’s of various metals, is laminated by fusion of actual metal, or, soldered in layers.
Shakudō and Shibuichi are both commonly used in Mokume-gane metal work. Box [A] was made by soldering in layers as follows:
1) Make the silver solder
- Same as with Shakudō, but with 2.925 Silver to 1 part Brass.
- Roll to a shim 6mm wide.
- Cut off 6mm square pieces.
2) Make sure the metals being used are flat and clean (must be no wider than 16mm or thicker than 0.7mm)
3) Place the shims on the metal, interspersed with calcified borax flux (flux is mixed with water to the viscosity of a liquid oil)
4) Put layers together (inner 5 layers) with the solder as in 5)
5) Use copper wire to bind the layers together (0.70 is sufficient)
6) Put on a charcoal reflector base (small pieces of charcoal in a metal tray)
7) Heat to the soldering temperature (see My Boxes). As they heat, the metals will pull into each other. You can see when the solder melts and the metal fuses together.
8) An thin ¼ inch iron bar can be used to help keep the metal together in the middle.
9) Let it cool.
There may be problems with air pockets and flux if large areas of metal are used. For box [A], this problem was avoided by using the 16mm wide sections (75mm long) .
If using sections, outer layers need to be whole. Proceed as follows:
10) Perforate the 2 outer layers using 1mm holes about 25mm apart. This gives the flux an air escape
11) Prepare clamping plates (just 2mm thick), by painting them with a chalk emulsion
12) Flat clamp the outer layers (copper and silver) to the billet
13) Put on the charcoal reflector base and heat as before
14) Let the completed billet cool
To make the decorative patterns:
15) Face cut the completed billet. (i.e. drill conical holes part the way through)
16) Be careful not to touch the inner copper layer.
17) Use the handheld bullet burr cutter to widen the holes and add detail to the patterns. (for box [A] I was trying to achieve a random pattern). The cuts require rounded bottoms.
18) If there are any defects or bubbles (up to 5%), these can be rectified by adding flux and re-soldering as necessary
19) Most of the perforations will have disappeared during the process, but if not, they can be drilled out and then rivets can be friction fitted and soldered in place (in box [A] I wanted to add rivets anyway to add further interest to the pattern). Make a rivet from 2mm square wire.
20) Press the metal from the back to the front so the patterns made from the layers are flush with the surface. Re-cut and repeat if needed.
21) Use light planishing to help to make it flatter. The billet will stretch, increase in size, and become thinner.
Roughly 35% of the metal is lost through drilling and cutting, but this can be sent for refining.
Note: with soldering, there is no need for rolling as when fusing the layers.