How Much Aluminum Hydroxide Can Be Added to Unsaturated Resin?

Aluminum hydroxide is an inert, odorless filler powder used in casting products to reduce shrinkage, increase weight, and improve flame resistance.

Aluminum hydroxide filler powder can be added to unsaturated resin at a maximum ratio of approximately 200% (i.e., 200 grams of filler powder per 100 grams of resin). This addition reduces shrinkage, significantly enhances thermal stability, and gives cast products more weight and solidity. However, higher filler powder content makes the resin harder to pour and reduces the surface detail of replicas.