Resin is a material originally created to solve utilitarian tasks. Everything changed after the appearance of brands that retain perfect transparency in the absence of bubbles, opacities and shade changes. In order to achieve the desired shape, ideal geometry, silicone molds are used in production.
Practice shows that silicone is the optimal raw material for the manufacture of molds. The walls are perfectly smooth. There is usually no need for mechanical modification of the finished product.
Even experienced craftsmen prefer the purchase of ready-made silicone molds for resin, rather than their independent production. Self-manufacturing is too difficult, you need to find the right silicone, mix it properly, prepare the plates for filling. Even a minimal error will lead to the fact that the finished form will be uneven, the probability of burr formation is high.