Silicone for moulds

The main difference between condensation-cure and addition-cure RTV silicone lies in the curing process, mold precision, and dimensional stability.

Condensation-cure RTV silicone is the most common option for crafts, decoration, figures, and general-purpose molds. It is more affordable, easy to use, and suitable for most applications involving resin, plaster, wax, or soap.

Addition-cure RTV silicone offers higher precision, lower shrinkage during curing, and a longer mold lifespan. It is the preferred choice for professional applications, highly detailed reproductions, or projects requiring maximum dimensional stability.

Addition-cure silicones also tend to provide better chemical and mechanical resistance, although they can be more sensitive to certain materials during the curing process.

The best silicone choice depends mainly on the type of piece, the casting material, and the level of detail or production required.

Standard RTV silicones are ideal for most decorative molds, crafts, resin, plaster, wax, or soap applications. They are easy to use and provide good flexibility and detail reproduction.

Thixotropic or brush-on silicone is recommended for large molds, vertical surfaces, or originals that cannot easily be submerged. It can be applied in layers without dripping.

For applications involving high temperatures, such as tin casting or low-melting alloys, a heat-resistant silicone capable of withstanding temperatures up to 350 °C is required.

Certified food-grade silicone is the correct option for chocolate molds, pastry making, or food-contact applications.

If maximum durability and repetitive production are needed, high mechanical resistance silicones provide longer mold life and better dimensional stability.

The curing time of mold-making silicone depends on the type of silicone, the catalyst ratio, and the ambient temperature.

Most RTV silicones cure within 6 to 24 hours at room temperature. Some fast-curing products can be demolded sooner, while technical silicones or thick molds may require additional time.

Temperature and humidity also affect the curing process. In general, lower temperatures increase curing time.

For a stable and durable mold, it is important to follow the manufacturer’s recommended mixing ratios and allow the silicone to fully cure before using it with resin or other casting materials.

The lifespan of a silicone mold depends on the type of silicone used, the casting material, and how well the mold is maintained during use and demolding.

A mold made with high-quality silicone can produce dozens or even hundreds of casts while maintaining good flexibility and detail reproduction.

Aggressive materials, high temperatures, or forced demolding can reduce the mold’s lifespan. For this reason, it is important to clean molds properly, avoid deformation, and store them in a dry place away from direct sunlight.

High mechanical resistance silicones are especially recommended for repetitive production or professional use.

Yes, mold-making silicone is fully compatible with most epoxy and polyurethane resins. In fact, it is one of the most commonly used materials for resin casting molds thanks to its flexibility and easy demolding properties.

Silicone allows highly detailed reproductions and prevents resin from sticking to the mold, making it possible to reuse the mold for multiple castings.

For best results, it is important to choose the right silicone according to the type of resin, working temperature, and production requirements.

For professional applications or repetitive production, high mechanical resistance silicones are recommended to extend the mold’s lifespan.

Thixotropic or brush-on silicone is recommended when the original piece cannot easily be submerged in liquid silicone or when working with large, vertical, or highly volumetric objects.

This type of silicone has a thicker consistency that allows it to be applied with a brush or spatula without dripping, making it ideal for molds on sculptures, figures, walls, or complex surfaces.

It is also very useful for reducing material consumption compared to traditional block molds, since only the surface of the original piece needs to be covered.

To create a strong and stable mold, several silicone layers are usually applied, followed by a rigid support shell.

Yes, certified food-grade silicone is specifically formulated for food-contact applications and is suitable for making chocolate molds, pastry molds, fondant molds, and other food-related creations.

This type of silicone is valued for its flexibility, easy demolding properties, and ability to reproduce fine details accurately, making it widely used in creative baking and artisanal confectionery.

To ensure food safety, it is important to use silicones that are officially certified for food contact and to follow the manufacturer’s instructions during mixing and curing.

It is also recommended to use dedicated tools and containers for food applications and maintain proper hygiene throughout the process.

To avoid bubbles in mold-making silicone, it is important to mix the components slowly and evenly to minimize air incorporation during preparation.

It is also recommended to pour the silicone slowly in a thin stream from a certain height, allowing trapped air to escape more easily before curing.

For highly detailed pieces, a common technique is to apply a thin first coat with a brush directly onto the original model before fully pouring the mold. This helps capture fine details and reduces surface bubbles.

Using a vacuum chamber or vibration system can further improve results in professional or highly technical mold-making applications.