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How to Make Liquid Silicone Rubber Molds or Tooling: A Comprehensive Guide

By 4.4 min readPublished On: May 24th, 2023Last Updated: May 24th, 2023Categories: Silicone industry knowledge


Liquid silicone rubber (LSR) molds or tooling play a crucial role in various industries, offering numerous benefits and applications. In this comprehensive guide, we will delve into the process of creating liquid silicone rubber molds or tooling, exploring their advantages, preparation techniques, mold making process, tooling process, and more. Whether you are a hobbyist or a professional, this article will provide you with valuable insights and step-by-step instructions to help you achieve high-quality results.

Understanding Liquid Silicone Rubber (LSR)

Liquid silicone rubber (LSR) is a versatile material known for its exceptional properties, making it ideal for mold making and tooling applications. With its excellent flexibility, heat resistance, durability, and chemical stability, LSR offers numerous advantages over traditional mold materials. These include precise replication of intricate details, high tear strength, low shrinkage, and the ability to withstand extreme temperatures.

Preparing for Mold Making or Tooling

Design and Preparation

When designing a mold or tooling, consider factors such as the desired shape, dimensions, and the type of material being molded or tooled. Accurate measurements and precise specifications are crucial for successful mold making or tooling, ensuring that the final product meets the intended requirements. Utilize computer-aided design (CAD) software for detailed and efficient mold or tooling designs.

Surface Preparation

Proper surface preparation is essential for achieving optimal mold quality. Thoroughly clean and prepare the surface to remove any dirt, debris, or contaminants that may affect the mold’s integrity. Techniques such as sanding, degreasing, and using mold-specific cleaning agents can enhance the surface quality and promote better adhesion of the liquid silicone rubber.

Mold Release Agents

To facilitate easy removal of the silicone mold from the original object or tooling, mold release agents are applied. These agents create a barrier between the liquid silicone rubber and the object being molded or tooled, preventing sticking or damage during the demolding process. Common types of mold release agents include silicone sprays, mold release pastes, and release films.

Mold Making Process

Mold Construction

Constructing a liquid silicone rubber mold requires attention to detail and precision. Begin by selecting an appropriate mold box and ensuring proper mold support. The mold box acts as a containment vessel for the liquid silicone rubber, while mold support ensures stability and accurate alignment during the pouring process.

Mixing and Pouring LSR

Properly mixing the liquid silicone rubber is crucial for achieving optimal mold quality. Follow the manufacturer’s instructions to ensure accurate mixing ratios and thoroughly degas the mixture to eliminate any trapped air bubbles. Carefully pour the liquid silicone rubber into the mold box, ensuring uniform coverage and avoiding any overflows.

Curing and Demolding

After pouring the liquid silicone rubber, allow it to cure according to the recommended time and temperature. Curing transforms the liquid rubber into a solid, flexible mold. Once cured, carefully demold the silicone mold, ensuring a gentle and controlled release to avoid any damage to the mold or the original object.

Tooling Process

Prototype Development

Prototyping plays a crucial role in the tooling process, allowing for testing and refinement before moving to full-scale production. Liquid silicone rubber is an excellent choice for prototyping due to its ability to accurately replicate complex geometries and its versatility across various industries. Utilize additive manufacturing techniques, such as 3D printing, to create prototypes for tooling.

Mold Creation for Tooling

Creating molds for tooling involves precision and attention to detail. Follow the same mold construction steps as mentioned in the mold making process, ensuring accurate mold dimensions and a smooth surface finish. For multi-cavity tooling, consider the design and layout of the mold to optimize production efficiency.

Injection or Compression Molding

Liquid silicone rubber offers exceptional properties for injection or compression molding. The material’s low viscosity allows for easy flow into intricate mold cavities, resulting in precise replication of details. Optimize molding parameters, such as temperature, pressure, and curing time, to achieve high-quality tooling products with excellent dimensional stability and surface finish.


Liquid silicone rubber molds or tooling provide a versatile and reliable solution for various industries. By following the comprehensive guide provided in this article, you can confidently embark on the journey of creating liquid silicone rubber molds or tooling. Remember to prioritize careful design, accurate preparation, and attention to detail throughout the mold making or tooling process. With the benefits of liquid silicone rubber and proper techniques, you can achieve outstanding results and unlock the full potential of your projects.


Q: How long does it take for liquid silicone rubber to cure?

A: The curing time for liquid silicone rubber varies based on the specific product and manufacturer’s instructions, typically ranging from a few hours to a day.

Q: Can I reuse liquid silicone rubber molds?

A: Yes, liquid silicone rubber molds are reusable. Proper demolding techniques and regular maintenance, such as cleaning and storage in a dust-free environment, can extend their lifespan.

Q: Can liquid silicone rubber molds withstand high temperatures?

A: Yes, liquid silicone rubber molds are known for their excellent heat resistance and can withstand high temperatures, making them suitable for various molding applications.

Q: Are there any safety precautions when working with liquid silicone rubber?

A: Yes, it is essential to follow safety guidelines provided by the manufacturer. This typically includes wearing protective gloves, goggles, and working in a well-ventilated area when handling liquid silicone rubber.