Casting resin - worth knowing about casting resin

Casting resin is a synthetic resin that is used to embed objects or as a casting compound. A casting resin can be both crystal clear and non-crystal.

Casting resins are mainly based on polyester resin, polyurethane resin and epoxy resin. The UV resistance and the favorable price can be highlighted as an important advantage of casting resin based on polyester resin. Casting resin based on epoxy resin has the advantage of low odor formation, very good adhesion properties, lower shrinkage and comparatively better mechanical properties. Polyurethane casting resin is very often used for quick impressions in silicone molds.

The difference between casting resin (glass-clear) and polyester resin or epoxy resin for laminating is that this resin is usually not processed with reinforcing fibers.

When processing, it is important to observe the maximum pouring height and the maximum pouring quantity. The maximum casting height is used to safely vent the casting resin. The maximum casting quantity ensures that the exothermicity during curing does not exceed the tolerances. Excessive exothermic reaction of the casting resin system during curing can lead to yellowing of the casting. This effect also occurs if you add too much hardener.

The pouring height and the pouring quantity are an important component of the casting resin. While you can reduce the hardener additive a little with the crystal-clear casting resin based on polyester resin, this is not possible with the crystal-clear epoxy casting resin and the polyurethane casting resin. The latter two are "set" for the respective quantities and pouring heights. It is important for epoxy casting resins that they are UV-stabilised. It is also very important for crystal-clear epoxy resins that they are crystal-clear, without a yellow tinge and not cloudy when pouring large quantities and high pouring heights.

Another important casting resin is polyurethane casting resin. Here, the fast casting resins play an important role. Polyurethane quick casting resins are preferably used for casting bodies and components where the crystal-clear appearance is not necessarily important, such as climbing holds and figures. Polyurethane resins can usually be filled very well with fillers such as quartz sand. This reduces component costs.