Middle black lacquer is used over both sabi, (jinoko or tonoko/lacquer mix) and mugiurushi, (flour/lacquer mix) as a layer to give you a smooth finish. Without a middle layer of lacquer it is very difficult to get a smooth enough finish to successfully apply a top layer of lacquer and then metal. Middle lacquer is not as hard as top lacquer.
Red lacquer is used in kintsugi for a substrate for metal. It is a good quality lacquer that can be polished out to a high sheen and is harder than middle lacquers.
Aluminium is also used in kintsugi. The grind of what I have is fine and since aluminium is so light it almost immediately becomes airborne when the package is opened.
The coarsest metal you can get ‘over the counter’ is #15. You can feel the grains with your fingers. It offers a visually textured finish although the surface of the polished metal is smooth. It is also very durable as the polished layer is so thick.
Number 10 silver and gold are very rough and need a lot of filling in of the grains in order to be able to polish them to a smooth surface. As the graded metal numbers get larger the grains of metal get larger and the finished polish shows more visual texture. The texture comes from the lacquer that fills in between the grains of metal. The larger grains also provide a thicker layer of metal that is a lot more durable.
Number 5 grind is about the coarsest that is usually used in kintsugi. #5 is also the point where you need to switch to a thicker hardening lacquer. You can’t really use regular, high quality lacquer as it is too thin. Using coarser metal than #5 is done sometimes. You will notice if you compare the magnified images of keshifun, #3, and #5 that the grains are getting bigger and the areas between the grains is turning more reddish since they are being filled with lacquer.
The photos show a reddish tint to the gold which is caused by the lacquer.
Metals that are ground coarser than the fine grind of keshifun are available in kintsugi. The graded, coarser metals go from #1–#15. #1 is the least coarse, #15 is the coarsest. In kintsugi the most common grades are from #1–#5. These metals require a completely different process to finish than the fine keshifun. The techniques are more akin to makie and require ‘filling’ in or hardening the coarser grains of metal onto the surface and then polishing the surface so it is smooth and shiny. It is easier to imagine sand paper to understand what is necessary. If you imagine #2000 grit sandpaper as a #1 grade and about #240 grit sandpaper as about a #15 grade you can understand how the metal gets coarser as the #1–#15 gets bigger. It isn’t possible to polish the graded metals as is. You need to fill in between the grains of metal with lacquer to first make a smooth surface and then come back in and then sand down both the lacquer and the tops of the metal to make a very tough and durable metal finish. A properly finished surface of graded metal is very durable. The photos show #3 silver in varying states of application, from applied and ‘hardened’,(the spaces between the grains of metal are filled in with lacquer) to finish polished. The coloring that appears in the unpolished samples is from the lacquer that is used to ‘harden’ the metal to the surface.
There are many types of metal that are used in kintsugi. This post will talk about the most common grind which is a fine powder and is called keshifun or keshi in Japanese.
This is what is mostly seen in pieces that are done with real kintsugi and have real gold or silver applied to them. It doesn’t need to be polished but it will take a burnishing if you want to. It is more durable if it is polished but that also makes it shinier. I prefer it matte so I usually don’t polish it. It also doesn’t need an overcoat of lacquer.
