What is casting resin? -The Basics
What is casting resin? Casting resin is a procedure of polymer casting in which a molten polymer is poured into a mould in which the mold cavity is already filled with an inert resin, that then hardens by means of solidification in the final casting. Resin casting is mostly used for small-to-medium scale manufacturing such as dentistry and industrial prototypes.
On the other hand, it’s not uncommon to find casting resin used for large-scale casting as well, as evidenced by the number of cast vehicles on display in car lots across the US. This is because, contrary to resin casting, the mixing of resins and molten metals is done only at the time of pouring the hot resin into the mould, making it easier for the workers to get the mixture just right before pouring it into the mould. With casting resin on the other hand, all of the mixing is done just prior to pouring the molten metal into the mould.
What is casting resin?
Casting resin is quite easy to use, and there are no stringent requirements for its use compared to other forms of polymer casting. The only requirement is that the substances being cast must have a high melting point and should be made of appropriate materials in order to avoid air inclusions.
Air inclusions are unfavorable for two reasons – they reduce the properties of the objects being cast, and they interfere with the properties of the final product once the objects are released from the moulds. To overcome air inclusions, the products are dipped into a hardener, such as sodium silicate, or boron nitride. Both of which have the properties to effectively prevent air from entering the cavity.
Aside from air bubbles, however, there are also other drawbacks associated with casting resin. Since the objects are poured into a container, there is an inherent tendency for the particles to cling to the sides of the container. Especially if there are folds in the sides of the container.
This, coupled with the fact that some parts of the objects are transparent (since the material is translucent), allows these particles to be seen when the objects are injected into molds.