You can coat the resin with as many layers as you want. If you see that the first layer poured has dust or air bubbles, the first step is to use sandpaper to remove air bubbles or dust before pouring another layer of resin onto the workpiece. Sanding the workpiece first will allow the hardened resin to have a matt surface, and this will make the next layer of resin coating adhere to the original surface more firmly. Consequently, the turbidity from the sandpaper will disappear when the next layer of resin is poured.