The Differences Between Platinum and Tin Cured RTV Mold Making Silicone

When it comes to mold making, silicone is a versatile material that offers various options. Two popular types of silicone used for mold making are platinum-cured and tin-cured RTV silicone. Understanding the differences between these silicone types is crucial in choosing the right option for your mold making projects.

Platinum-cured silicone gets its name from the catalyst used to cure the silicone: platinum. This type of silicone offers several advantages, including longer library life, FDA compliance for food and skin contact, and high heat resistance. On the other hand, tin-cured silicone, as the name suggests, uses tin as the catalyst for curing. It is generally less expensive than platinum-cured silicone.

Whether you're casting molds for intricate designs or creating molds for functional parts, understanding the unique properties of each silicone type is essential. From curing processes to shrinkage and compatibility, this article explores the key differences between platinum and tin-cured RTV mold making silicone and provides insights into their specific applications and considerations.

Key Takeaways:

• Platinum-cured and tin-cured RTV silicone are two main types of silicone used for mold making.
• Platinum-cured silicone offers advantages such as longer library life, FDA compliance, and high heat resistance.
• Tin-cured silicone is generally less expensive than platinum-cured silicone.
• Consider factors such as silicone shrinkage, production life, and temperature and chemical resistance when choosing between the two types.
• Compatibility with casting materials and post-curing procedures are also important considerations in mold making.

Silicone Properties and Uses

Silicone rubber is a versatile material widely used for various applications, including mold making. Its outstanding properties make it an ideal choice for creating high-quality silicone molds.

One of the key advantages of silicone is its strength and flexibility. It can withstand considerable stress without losing its structural integrity, making it highly durable for long-lasting molds.

Moreover, silicone exhibits self-releasing characteristics, which means that it easily releases castings without the need for excessive force or mold release agents. This property simplifies the demolding process and ensures clean and precise reproduction of intricate details.

When working with silicone molds, it is important to consider factors such as silicone toxicity and the use of food-grade silicone for applications involving food or skin contact. Using food-grade silicone ensures safety and compliance with regulations, providing peace of mind for projects involving culinary creations or skin-friendly products.

In addition, mold release agents can be employed to further facilitate the demolding process. These agents create a barrier between the mold and the casting material, preventing adhesion and allowing for easy separation.

To enhance specific properties of silicone, various additives can be incorporated. For instance, additives can improve the flexibility of silicone, enabling it to conform to intricate shapes and contours effectively.

Overall, silicone's exceptional properties, including strength, flexibility, self-releasing characteristics, and the ability to incorporate additives, make it a preferred choice for mold making applications.

Advantages of Silicone for Mold Making:

• High strength and flexibility for durable molds
• Self-releasing properties for easy demolding
• Food-grade silicone for safe use with food and skin contact
• Mold release agents for effortless separation of castings
• Additives to enhance flexibility and improve mold performance

Curing and Inhibition of Silicone

All silicone rubbers can be subject to cure inhibition, especially when contaminants are present on the surface of the model being used for mold making. It's important to understand the factors that can affect the curing process and how to prevent cure inhibition to ensure successful mold creation.

Cure Inhibition in RTV Silicone Processes

Cure inhibition refers to the condition where the silicone does not fully cure, resulting in a tacky or sticky surface that cannot be demolded properly. This can be frustrating and impact the quality of your mold. It's essential to identify the potential causes of cure inhibition and take the necessary precautions.

One common cause of cure inhibition is the presence of sulfur. Platinum-cured silicone is particularly sensitive to sulfur and will not cure when exposed to it. Therefore, it is crucial to avoid using sulfur-containing materials or working in environments with high sulfur content when using platinum-cured silicone. Sulfur is contained in some clays so if you are planning to create a mold of modeled clay that contains sulphur you will need to seal the surface so that silicone does not come into contact with it.

On the other hand, tin-cured silicone can cure over models containing sulfur if the surface is properly prepared. Applying an acrylic spray on the surface can seal off the sulfur, allowing the silicone to cure without inhibition.

Silicone Mold Release Techniques

In addition to curing inhibition caused by sulfur, certain substrates and adhesives can also lead to inhibition in platinum-cured silicone. It's important to ensure compatibility between the silicone and the materials it meets. Testing a small amount of the silicone on the intended substrate can help determine if any inhibition issues might arise.

Furthermore, using effective mold release techniques can help prevent cure inhibition. Mold release agents create a barrier between the silicone and the substrate, preventing any contaminants from interfering with the curing process. Applying a thin, even layer of a suitable mold release agent can significantly reduce the risk of cure inhibition.

Cure Inhibition Caused by Poisonous Substrates

It is worth noting that cure inhibition can also be caused by poisonous substrates. When working with substrates that contain poisonous materials or residues, it is crucial to take appropriate safety precautions, such as wearing protective gloves and working in a well-ventilated area.

Understanding the causes of cure inhibition and implementing preventive measures can help ensure successful silicone mold making. By taking the necessary steps to avoid cure inhibition, you can create high-quality molds that produce the desired results.

Shrinkage and Library Life of Silicone

One of the key factors to consider when choosing between tin-cured and platinum-cured silicone for your mold making projects is the issue of shrinkage. Shrinkage refers to the change in size that occurs in silicone molds over time. It is a critical consideration as it can affect the accuracy and integrity of the final castings.

Tin-cured silicone molds generally exhibit higher levels of shrinkage compared to platinum-cured silicone molds. This means that over time, tin-cured molds can experience dimensional changes that may result in inaccuracies or distortions in the castings.

Moreover, the library life of silicone is an important factor to consider. The library life refers to the longevity of the silicone molds, especially if you plan to reuse them for multiple castings over an extended period.

Tin-cured silicone molds typically have a limited library life, typically around 12 months. This means that after this time, the molds may start to degrade or lose their dimensional stability, resulting in reduced casting quality.

In contrast, platinum-cured silicone molds have a much longer library life, measured in decades. These molds offer extended usability and durability. With proper care and maintenance, platinum-cured silicone molds can retain their dimensional accuracy and produce high-quality castings for many years.

Moreover, the shelf life of platinum and tin silicone also differs. While both types of silicone have a finite shelf life, tin-cured silicone tends to have a shorter shelf life compared to platinum-cured silicone. This means that tin-cured silicone may have a shorter expiration date and may need to be replaced more frequently.

Shrinkage Comparison between Tin-Cured and Platinum-Cured Silicone:

Library Life Comparison:

Understanding the shrinkage and library life of silicone can help you make an informed decision when selecting the right type of silicone for your mold making projects. Consider the specific requirements of your application and the longevity you need from your molds to ensure successful and durable end results.

Production Life and Application Specificity

The production life of silicone molds is an essential consideration when it comes to mold making. It refers to the longevity of the molds for casting various materials and can vary depending on different variables and application-specific requirements.

To ensure the best results and maximize the production life of silicone molds, it is crucial to follow certain best practices for curing. These practices include proper mixing ratios, adequate mold release agents, and appropriate post-curing procedures. By adhering to these practices, you can enhance the durability and performance of your silicone molds.

When it comes to mold making, platinum-cured silicone offers distinct advantages in terms of production life and application specificity. Platinum silicone mold making techniques can ensure longer-lasting molds and superior heat resistance, making them particularly suitable for applications that involve higher temperatures or extended production cycles.

A key point to note is that platinum-cured silicone has a longer shelf life compared to tin-cured silicone. This allows for extended usability and storage time, which can be beneficial for projects where a mold might be required intermittently or over a longer period.

To provide further insight into the production life and application specificity of silicone molds, let's consider a table that compares the key features and capabilities of platinum-cured and tin-cured silicone:

Table: Comparison of Platinum-Cured and Tin-Cured Silicone for Mold Making

By considering these factors and understanding the specific requirements of your mold making project, you can make an informed decision regarding the choice of silicone and techniques to ensure the desired production life and performance.

Compatibility and Considerations

When using silicone molds for casting, it is essential to ensure compatibility between the casting resin or material and the cured silicone molds. Conducting a small compatibility test is recommended to ensure satisfactory results. Take a small amount of the casting resin and apply it to a cured silicone sample, observing any adverse reactions or issues that may arise.

Aside from compatibility, there are other important considerations in silicone mold making. It is crucial to prioritize health and safety practices to protect yourself and others involved in the process. This includes wearing personal protective equipment (PPE), such as gloves, goggles, and masks, and working in a well-ventilated area.

Furthermore, post-curing procedures can greatly enhance the properties of silicone molds. Post-curing involves subjecting the cured molds to additional heating or curing processes to optimize their performance. This can improve the durability, tear strength, and overall quality of the molds, ensuring optimal results in the casting process.

Another factor to consider is the flexibility of silicone molds. Enhancing flexibility can be achieved by using specific techniques during the mold-making process, such as adding silicone additives such as silicone oil, or adjusting the ratio of the silicone components. This allows for easier demolding and increased flexibility in complex or intricate designs.

Health and Safety Guidelines for Silicone Mold Making

Note: Always consult the specific safety data sheets (SDS) provided by the silicone manufacturer for comprehensive health and safety information.

Cost Comparison and Eco-Friendliness

When it comes to choosing the right silicone for your mold making projects, cost and eco-friendliness are two important factors to consider. In this section, we will explore the cost comparison between platinum and tin-cured silicone, as well as the eco-friendly aspects of tin-cured silicone.

Cost Comparison

One of the major considerations in selecting silicone for mold making is the cost. Tin-cured silicone is generally much more affordable compared to platinum-cured silicone. This makes it a cost-effective option, especially for projects with budget constraints.

Although platinum-cured silicone may be more expensive upfront, it offers advantages such as longer library life and high heat resistance. This can result in cost savings over the long term, as you may not need to replace the molds as frequently as with tin-cured silicone.

Eco-Friendly Aspects

In addition to cost, the eco-friendly aspects of silicone are becoming increasingly important. Tin-cured silicone has certain eco-friendly advantages that make it a popular choice in certain applications.

Tin-cured silicone is condensation cured, meaning it does not rely on heat for curing. This can be advantageous in projects where heat may not be readily available or desirable. Additionally, the curing process of tin-cured silicone produces fewer byproducts compared to platinum-cured silicone, reducing its environmental impact.

As shown in the table above, tin-cured silicone offers cost advantages and eco-friendly aspects that can make it a suitable choice for certain mold making projects. However, it's important to carefully evaluate your specific requirements and consider the trade-offs between cost, performance, and sustainability when making your decision.

Temperature and Chemical Resistance

In the world of mold making, the properties of silicone play a crucial role in determining its suitability for various applications. Two key factors to consider are temperature resistance and chemical resistance. Let's explore how platinum-cured and tin-cured silicone differ in these aspects.

Temperature Resistance:

Platinum-cured silicone is known for its exceptional heat resistance, making it an excellent choice for applications that require the material to withstand high temperatures. With a high heat deflection of up to 400°F, platinum silicone molds can maintain their structural integrity even under extreme heat conditions, ensuring reliable performance and durability.

On the other hand, tin-cured silicone excels in its chemical resistance properties. This makes it particularly beneficial for mold making projects that involve frequent contact with chemicals or aggressive substances. By withstanding the effects of harsh chemicals, tin silicone molds offer enhanced longevity and the ability to maintain their shape and function over time.

When choosing between platinum-cured and tin-cured silicone for your mold making needs, it is important to assess the specific temperature and chemical requirements of your project. Consider the table above to determine which type of silicone offers the optimal resistance for your application, ensuring long-lasting and reliable results.

Conclusion

When it comes to mold making, the choice between platinum-cured and tin-cured silicone is crucial. Factors such as durability and tear strength play a significant role in selecting the right silicone for detailed mold casting. The impact of humidity on silicone curing cannot be ignored, as it can affect the final quality of the molds.

Platinum-cured silicone stands out in the field of medical molds due to its superior properties and safety considerations. Its durability, tear strength, and resistance make it an excellent choice for medical applications where precision and reliability are paramount.

Selecting the right silicone for mold casting is a key decision. Whether it is for medical molds or other applications, understanding the impact of humidity on silicone curing, and considering factors such as silicone's durability and tear strength, will help ensure successful and high-quality mold making.

FAQ (Frequently Asked Questions) :

What are the differences between platinum and tin cured RTV mold making silicone?

Platinum-cured silicone uses platinum as the catalyst for curing, while tin-cured silicone uses tin. Platinum-cured silicone offers advantages such as longer library life, FDA compliance for food and skin contact, and high heat resistance compared to tin-cured silicone.

What are the properties and uses of silicone?

Silicone rubber has excellent properties such as strength, flexibility, and self-releasing characteristics, making it an ideal material for mold making. It is used for creating silicone molds, mold release, and can be formulated as food grade silicone for safe use with food and skin contact.

What factors should I consider for curing and inhibition of silicone?

Silicone can be subject to cure inhibition, especially if there are contaminants present on the model surface. Platinum-cured silicone is particularly sensitive to sulfur and will not cure when exposed to it. Tin-cured silicone can cure over models containing sulfur if the surface is sealed with an acrylic spray. Additionally, certain substrates and adhesives can cause inhibition in platinum-cured silicone.

What is the shrinkage and library life of silicone?

Tin-cured silicone molds generally exhibit higher shrinkage over time compared to platinum-cured silicone molds. The library life of tin-cured silicone molds is typically around 12 months, while platinum-cured silicone molds have a much longer library life, measured in decades. The shelf life of platinum and tin silicone also differs, with tin-cured silicone having a shorter shelf life.

How long does the production life of silicone molds last?

The production life of silicone molds, which refers to their longevity for casting various materials, depends on different variables and is usually application specific. Best practices should be followed for curing silicone molds, and specific techniques for using platinum-cured silicone can be employed to enhance production life and heat resistance.

What considerations should I have for compatibility and other factors?

Compatibility between casting resins or materials and the cured silicone molds is important, and testing a small amount of the casting resin with a cured silicone sample is recommended. Other considerations include health and safety practices in silicone mold making, post-curing procedures to optimize the properties of the silicone molds, and techniques for enhancing flexibility in silicone molds.

Which type of silicone is more cost-effective and eco-friendlier?

Tin-cured silicone is generally less expensive compared to platinum-cured silicone, making it a more cost-effective option for certain mold making projects. Tin-cured silicone also has eco-friendly aspects as it is condensation cured and does not rely on heat for curing, which can be advantageous in certain applications.

How do temperature and chemical resistance differ between platinum and tin-cured silicone?

Platinum-cured silicone offers high heat deflection and can withstand temperatures up to 400°F, making it suitable for applications requiring temperature resistance. On the other hand, tin-cured silicone exhibits good chemical resistance, which can be beneficial for certain mold making projects involving contact with chemicals or aggressive substances.

What are the key considerations when choosing between platinum and tin-cured silicone for mold making?

When choosing between platinum and tin-cured silicone for mold making, it is important to consider factors such as durability, tear strength, and suitability for specific applications. The impact of humidity on silicone curing should also be taken into account. Platinum-cured silicone is often preferred for medical molds due to its superior properties and safety considerations.