Choosing the right silicone material ensures your gasket, seal, or molded part performs reliably. Using the wrong type can lead to poor curing, weak seals, or production delays.
HTV (High Temperature Vulcanizing) silicone is cured at high temperatures and is used for molded and extruded parts. RTV (Room Temperature Vulcanizing) silicone cures at room temperature and is used as a sealant, adhesive, or for in-place gaskets and molds.
Many customers ask me to clarify the difference when specifying silicone for automotive, industrial, or electrical projects. Here’s what you need to know.
What Is HTV Silicone?
HTV silicone starts as a solid, gum-like material. It is shaped by molding or extrusion, then cured at high temperatures (typically 160°C to 200°C). The result is a durable, elastic rubber with excellent mechanical properties.
HTV silicone is ideal for manufacturing pre-molded parts such as O-rings, gaskets, tubing, and custom profiles that require precise dimensions and consistent quality.
Key Features of HTV Silicone
| Property | HTV Silicone |
|---|---|
| Curing Temperature1 | High (160–200°C) |
| Form Before Cure | Solid gum, sheets |
| Typical Applications | Molded parts, extrusions |
| Mechanical Properties2 | Excellent |
| Production Volume | High |
What Is RTV Silicone?
RTV silicone3 is supplied as a paste or liquid and cures at room temperature, usually when exposed to air moisture. It is commonly used as a sealant, adhesive, in-place gasket, or for flexible mold making.
RTV silicone is perfect for field repairs, sealing, bonding, and custom in-place gaskets where traditional molded parts aren’t available or surfaces are irregular.
Key Features of RTV Silicone
| Property | RTV Silicone |
|---|---|
| Curing Temperature1 | Room temperature (20–30°C) |
| Form Before Cure | Liquid or paste |
| Typical Applications | Sealants, adhesives, in-place gaskets, molds |
| Mechanical Properties2 | Good (varies by formulation) |
| Production Volume | Small, field/repair use |
Side-by-Side Comparison: HTV vs RTV Silicone
| Feature | HTV Silicone4 | RTV Silicone |
|---|---|---|
| Curing Process5 | High temp (oven/press) | Room temp (air/moisture) |
| Initial Form | Solid gum/sheet | Liquid or paste |
| End Use | Molded/extruded parts | Sealants, adhesives, molds |
| Typical Application | High-volume production | Field repairs6, custom gaskets |
| Dimensional Precision | High | Medium |
| Flexibility7 | High | High |
When Should You Use HTV or RTV Silicone?
- Choose HTV silicone for molded or extruded parts in large production runs, such as O-rings, profiles, and tubing, where you need high strength, consistent dimensions, and durability.
- Choose RTV silicone for on-site sealing, bonding, maintenance, or when you need to form a gasket or part directly on the equipment.
Quick Selection Guide
| Requirement | HTV Silicone ✅ | RTV Silicone ✅ |
|---|---|---|
| Molded gaskets/O-rings8 | ✅ | |
| On-site repairs/sealing | ✅ | |
| High-precision production | ✅ | |
| Custom, in-place gaskets | ✅ |
Conclusion
HTV silicone is for high-temperature-cured, molded, or extruded parts, perfect for precision and high-volume needs. RTV silicone is for room-temperature-cured, on-site applications like sealing, bonding, and custom gaskets.
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Understanding curing temperature is crucial for selecting the right silicone for your needs, ensuring optimal performance. ↩ ↩
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Learn how mechanical properties influence the effectiveness of silicone in different applications, ensuring you choose the best option. ↩ ↩
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Explore the benefits of RTV silicone for various applications, including sealing and bonding, to enhance your projects. ↩
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Explore this resource to understand HTV silicone's advantages and its diverse applications in manufacturing. ↩
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Understanding the curing process is essential for selecting the right silicone for your project, ensuring optimal performance. ↩
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Discover best practices for using RTV silicone in field repairs to ensure durability and effectiveness in your projects. ↩
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Understanding flexibility in silicone can enhance your material selection for various applications, ensuring optimal performance. ↩
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Explore this resource to discover the best materials and techniques for creating durable molded gaskets and O-rings. ↩
