A wooden, straight palette knife is traditionally used in kintsugi. There are a couple of qualities of wood and thickness with the thinner one being of higher quality.
This is a tool used for sprinkling the metal on the lacquer. You load it up in the open end and the metal comes out the meshed end. The mesh stops any debris in the metal from coming out.
The video shows sanding sabi. I am using a wood handle with 2 types of tips, a diamond one and a whet stone tip.
For more on traditional, lacquer based kintsugi see kintugi.com
The video shows step between 5 and 6, sanding sabi. This piece is still far from being finished. The surface is very rough and so is difficult to get a good finish.
The steps refer to this page, https://www.kintugi.com/?page_id=80
For more on traditional, lacquer based kintsugi see kintugi.com