Many buyers struggle with material choices, leading to product failure or extra costs. Confusion between RTV and silicone rubber is common, especially in industrial and maintenance projects.
RTV silicone is a specific type of silicone rubber that cures at room temperature, mainly for sealing and adhesive applications, while silicone rubber is a broad material category that includes various types and curing methods for different uses.
When I work with new clients, I often find they do not realize that RTV is just one sub-type within the big family of silicone rubbers. Getting this detail wrong can create sourcing and quality problems. Let’s explore these differences with clarity.
What is RTV silicone? How does it fit into the silicone rubber family?
People often think RTV is a different material, but it is actually a subtype. I learned this early in my career when a supplier shipped the wrong product.
RTV stands for Room Temperature Vulcanizing. It describes silicone rubber that cures and hardens at ambient temperatures, typically by reacting with moisture in the air. Silicone rubber, by contrast, is a general name for synthetic rubbers made from silicon, oxygen, carbon, and hydrogen.
🛠️ Main Types and Curing Processes
| Type of Silicone Rubber | Curing Process1 | Main Features |
|---|---|---|
| RTV Silicone2 | Cures at room temperature (via moisture or other agents) | Good for field use, easy application |
| HTV (High-Temperature Vulcanization)3 | Cures under heat in a factory | Precise, used for molded parts |
| LSR (Liquid Silicone Rubber)4 | Injection molding, high heat | High purity, complex shapes, medical |
| HCR (High Consistency Rubber)5 | Similar to HTV, higher viscosity | Rollers, sheets, extrusions |
I always ask clients to confirm their curing requirements when placing a silicone rubber order. Not all silicone rubbers are interchangeable.
What are the key chemical and mechanical differences between RTV and other silicone rubbers?
Choosing the right type goes beyond just curing method. It’s also about formulation and application.
RTV silicones include additives and crosslinking agents that let them cure at room temperature. Other silicone rubbers, like HTV, LSR, or HCR, have formulas optimized for factory processing, higher temperatures, or unique mechanical properties.
Key Mechanical Differences
| Property | RTV Silicone2 | HTV/LSR Silicone Rubbers |
|---|---|---|
| Curing temperature6 | Room temp (50–86°F) | High temp (oven, press, mold) |
| Strength (general) | Moderate to high (some grades are very strong) | Varies from soft to very strong |
| Application method | Applied in field, tool, or assembly | Factory only |
| Surface bonding | Bonds well to many substrates | Not designed as an adhesive |
I have found that high-strength RTV silicone, like special high-temp grades, can sometimes match or exceed factory-molded parts for certain applications, but not for all.
What are the main uses and advantages of RTV silicone compared to general silicone rubber7?
Misuse of these materials is common. For example, I have seen clients use RTV where a certified molded gasket was required, causing compliance issues.
RTV silicone is used for sealing, bonding, potting electronics, construction joints, automotive gasket making, and mold fabrication—especially when field application or fast repairs are needed. Silicone rubber in general is chosen for gaskets, hoses, medical implants, insulation, and food-grade products.
Application Comparison Table
| Application Scenario8 | RTV Silicone2 | General Silicone Rubber |
|---|---|---|
| On-site repairs | ✅ | |
| OEM molded components | ✅ | |
| High-precision gaskets | Limited | ✅ |
| Adhesive/sealant | ✅ | Sometimes |
| Food or medical grade | Special RTV only | Many grades available |
| Mass production | ✅ |
I recommend RTV for its ease of use and quick cure in repairs or prototyping. I specify molded or extruded silicone rubber for production parts, especially where regulatory certification, repeatability, or tight tolerances are critical.
How do strength, durability, and cost compare between RTV and other silicone rubbers?
One buyer asked if using RTV would save money long-term for large gasket orders. The answer is usually no, except for short-run or unique repairs.
RTV silicone can be strong and durable, especially in high-temperature or specialized versions, but mass-produced silicone rubber parts are usually more cost-effective, offer higher consistency, and can be engineered for even greater performance.
Strength, Durability, and Cost Table
| Factor | RTV Silicone | Molded Silicone Rubber |
|---|---|---|
| Initial Cost (small runs) | Lower | Higher (tooling, setup) |
| Cost per piece (volume) | Higher | Lower (mass production) |
| Max Strength | High for some types | Can be engineered higher |
| Long-term Durability9 | Good, but grade-dependent | Excellent, grade-dependent |
| Certified performance10 | Limited, some grades only | Many options available |
For field repairs or quick fixes, RTV is a smart choice. For production and projects where quality, certification, and long-term cost matter, I always select the right silicone rubber grade and curing process.
When should I use RTV, and when should I specify another type of silicone rubber?
I advise all my customers: Match your material to your actual need, not just what is available.
Use RTV when you need an on-site sealant, field repair, or mold. Use molded, extruded, or injection silicone rubber for production, compliance, tight tolerances, or specialized needs.
Quick Decision Guide
| Scenario | Use RTV? | Use Molded/LSR/HTV? |
|---|---|---|
| Field assembly or repair | ✅ | |
| High-volume, OEM gasket | ✅ | |
| Custom shape, one-off | ✅ | |
| Food, medical, certified part | Limited | ✅ |
| High chemical/heat resistance | Special grades | ✅ |
My own story: When our client needed 500 food-grade gaskets, I insisted on using platinum-cured LSR to ensure compliance. For their urgent maintenance needs, RTV sealant was the best tool.
Conclusion
Understanding the difference between RTV and silicone rubber lets me make the right material decisions, reduce risk, and ensure product quality.
-
Understand the various curing processes and how they affect silicone rubber performance. ↩
-
Explore the advantages of RTV Silicone for various applications, including its ease of use and quick curing. ↩ ↩ ↩
-
Learn about HTV silicone's unique properties and its suitability for high-temperature applications. ↩
-
Discover the versatility of LSR silicone in medical and complex shape applications. ↩
-
Find out how HCR silicone is utilized in manufacturing rollers, sheets, and extrusions. ↩
-
Understanding curing temperature is crucial for selecting the right silicone rubber for specific applications, ensuring optimal performance. ↩
-
Explore this resource to understand the diverse applications and advantages of general silicone rubber in various industries. ↩
-
Discover the ideal scenarios for using RTV silicone and when to choose other types. ↩
-
Find out about the durability of RTV silicone and how it stacks up against other silicone types. ↩
-
Understand the importance of certified performance in silicone rubber for compliance and quality. ↩
