Barter is the present and the future of international trade, especially for people who is starting in the import export business. Barter and more: Triangular operations.
The choice of metallographic sandpaper
This material does not matter much, no matter the material is soft or hard, it has to go through the process of rough grinding, fine grinding, polishing and corrosion. Generally, 100# 200# 400# 600# 800# 1000# can be selected. If one or two kinds are missing in the middle, it does not matter. The spring steel is relatively hard, and it should be better to grind the metallographic phase, because the softer the material, the easier it is to form. scratches. Sandpaper is composed of dry sandpaper and water sandpaper. We generally choose water sandpaper, but you can choose according to your own situation. The brand of sandpaper is very important. We chose Eagle brand for water sandpaper, but there are many fake ones, so pay attention to distinguish them. Dry sandpaper appears to be diamond. When choosing, look at the thickness of the sandpaper, it must not be too thin, and whether the sand is firm and evenly distributed.
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