What type of silicone is best for mold making?

Choosing the right silicone affects strength, detail clarity, and lifespan. The most commonly used types include:

• Tin-Cure (Condensation-Cure) Silicone: It is flexible, easy to use, works well under short-run circumstances, and is the least expensive mold rubber. Slight shrinkage may occur with time.
• Platinum-Cure (Addition-Cure) Silicone: High tear strength, long mold life, and excellent reproduction of details make it suitable for medical, food-grade, and industrial parts.
• High-Temperature Silicone: This is meant for parts exposed to heat, typically employed for automotive or electronics applications.
• High-Durometer Silicone: High-durometer silicone is more rigid and is useful when a mold needs to maintain strong dimensional stability. The best silicone depends on your application. Food-safe molds, for instance, require FDA-compliant platinum-cure silicone; industrial parts might require a high-durometer grade that withstands abrasion and mechanical stress.

How to calculate the amount of silicone needed for mold design?

The correct volume calculation prevents waste and ensures that the mold is filled. The general formula for determining silicone volume is as follows:

Volume = Mold Box Volume – Master Pattern Volume Steps to Calculate Silicone Volume:

• Measure the mold box (Length × Width × Height).
• Measure the master pattern or 3D model volume using CAD or by the method of water displacement.
• Subtract the pattern volume from the mold box volume to get the silicone volume.
• Convert cubic centimeters (cc) or cubic inches into grams if needed, based on silicone density.

How long does curing take for different silicone grades?

• Tin-Cure Silicone: Tin-cure silicone generally cures at room temperature in the range of six to twenty-four hours, according to the type and thickness of the mold. Some faster-curing types are available, usually curing in three to six hours, suitable for quick turnarounds.
• Platinum-Cure Silicone: Platinum-cured silicones usually cure at room temperature over a period of 4 to 24 hours, giving excellent, strong, high-definition results. When applying heat, the cure time is dramatically reduced to usually 1 to 2 hours at approximately 60–70 °C, thus making it an asset when speeding up the production line.
• High-Performance Industrial Silicones: In the case of high-performance silicones, it is capable of doing very tough and fast cures, usually within the range of 30-90 minutes, when heated. It is used for making medical parts, in electronics, and for prototyping, fast and accurately. Adding heat to the silicone increases the curing speed. In addition, thicker molds usually require a longer period to set compared to thin ones, which harden up quickly.