There are many types of metal that are used in kintsugi. This post will talk about the most common grind used which is a fine powder and is called keshifun in Japanese.
This is what is mostly seen in pieces that are done using kintsugi techniques. Keshifun 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. If you apply one it will dampen the shine somewhat. Keshifun is a flat grind. The particles are flat, not round.
There are several types of flat grind gold and silver. Hirame is rounded metal flattened out into a round shape, it comes in grades of #1 to #13 size. Also there is nashiji which is hirame thinned out in to oval, strip shapes, it comes in grades of #1 to #10.