Mold Making and Casting

Frequently Asked Questions

  • Why is my alginate lumpy?

    Alginate is very sensitive to the mineral content of the water you use, and lumpy alginate is generally a symptom of hard water. Be sure to do a small test with your specific water source before embarking on a large project or, for best results, use distilled water.

  • Why didn’t my silicone cure?

    Cure inhibition can have many causes. Common ones are insufficient mixing or inaccurate measuring of components, or contact with known cure inhibitors like sulfur and natural latex. Read all directions thoroughly and conduct a small-scale test with your specific materials to avoid issues with your mold-making project.

  • What can I use for life casting?

    Some platinum-cure silicones are skin-safe and make durable, reusable molds, as are many alginates, which are best suited to short-term, single-use molds. Plaster gauze is traditional for life-casting, but care should be exercised as plaster is very drying to skin and gets hot as it cures, so it has the potential to cause skin irritation. Just be sure whatever product you choose is appropriate for skin application, and closely follow directions for use.

  • What is a mother mold and do I need one? If I need one, what do I make it from?

    Some platinum-cure silicones are skin-safe and make durable, reusable molds, as are many alginates, which are best suited to short-term, single-use molds. Plaster gauze is traditional for life-casting, but care should be exercised as plaster is very drying to skin and gets hot as it cures, so it has the potential to cause skin irritation. Just be sure whatever product you choose is appropriate for skin application, and closely follow directions for use.

  • Will latex be damaged if I order in winter and it freezes? What about silicone?

    Latex cannot survive freezing, so try to time your order so that it won't be frozen in transit. Silicone and urethanes are not harmed by freezing, but they may thicken and separate. Since you'll be stirring each part for the recommended time prior to use anyway, this separation will not cause any issues when you use the product. And if your latex does happen to arrive frozen, just call our Customer Care Team at 1-800-723-2787.