How much do you know about RTV silicone? Are you worried about choosing the wrong type, affecting the performance of the product and production rhythm? This article will provide you with a comprehensive introduction to RTV silicone, and how to buy the right type for you. I believe that after reading this article, it will be a great help to your decision-making.
What is RTV Silicone
RTV silicone is a greenhouse cured silicone rubber. It does not require heat and cures at room temperature using only the reaction of moisture in the air. It can with bond to many types of substrates and is easy to use. It has good resistance to high temperature and aging, so it is widely used.
How RTV Silicone Works
RTV silicone is composed of a silicone rubber polymer matrix (silicon, oxygen, carbon, hydrogen and other elements), crosslinking agents and fillers. The silicone rubber polymer is mainly a silicone-oxygen chain structure, which has good elasticity and high temperature resistance. The cross-linking agent is responsible for helping the liquid RTV silicone gel to react with moisture in the air to form a silicone-oxygen cross-linking structure, which then becomes a solid state. Fillers are regulating the mechanical hardness, fluidity, color, etc. of the solidified RTV silicone. Different types of crosslinkers and fillers affect different physical properties of RTV silicone, such as its abrasion resistance, elasticity, temperature resistance, and curing speed.
Below is a table summarizing the effects of different types of crosslinkers and fillers on the physical properties of RTV silicone.
| Type | Crosslinker/Filler | Effect | Description |
| Crosslinker
| Amino Silane (AMMO) | Increases hardness, adhesion, and water resistance | Enhances adhesion, suitable for humid environments. |
| Vinyl Silane (V-Silane) | Increases elasticity and temperature resistance | Improves flexibility, suitable for high-temperature environments. | |
| Silica (SiO₂) | Chemical resistance, heat resistance, increases hardness | Improves heat resistance and chemical resistance. | |
| Filler
| Silica (SiO₂) | Increases hardness, adhesion, and reduces expansion | Enhances strength and stability. |
| Titanium Dioxide (TiO₂) | Enhances UV resistance, improves weatherability | Increases UV resistance, suitable for outdoor use. | |
| Graphite Powder (Graphite) | Improves thermal conductivity, increases wear resistance | Enhances heat conductivity and wear resistance. | |
| Alumina (Al₂O₃) | Increases wear resistance, high-temperature resistance | Enhances wear resistance and high-temperature stability. | |
| PTFE (Polytetrafluoroethylene) | Reduces friction, improves chemical stability | Improves chemical resistance, suitable for low-friction applications. | |
| Carbon Black (Carbon Black) | Enhances UV resistance, improves electrical performance, and increases toughness | Increases UV resistance and electrical protection. |
General Properties of RTV Silicone
Elasticity and Flexibility: RTV silicone has good elasticity and flexibility after curing. It can withstand stretching without losing adhesion, and can be compressed and bent at will without losing its stable performance.
Temperature resistance: It can withstand large temperature differences. From -50℃ to 250℃, RTV silicone can withstand and play its role normally. It has a very low coefficient of thermal expansion, and the amplitude change is very small when the temperature fluctuates.
UV resistance: RTV silicone will not age or decompose quickly under strong sunlight.
Low volatility: RTV silicone in the curing process, only in the release of a small amount of volatile organic compounds. Will not cause environmental pollution.
Insulation: There are no free electrons and ions in the molecular structure of RTV silicone, the molecular skeleton is stable and non-polar. It can isolate the current and prevent short circuit or leakage.
Good adhesion: It has good adhesion and can be adhered to metal, ceramic, glass, plastic, and coated surfaces. (Different crosslinking agents and formulations can improve its adhesion.)
Waterproof and sealing: After curing, it forms a continuous rubber-like film with no gaps or cracks, and neutral liquids, such as water, cannot penetrate. Moreover, it has good temperature resistance and can be adhered to the surface of the substrate with its good adhesive force to form a closed state, preventing the entry of water, dust and air. In a large temperature difference can still be stable performance, not because of thermal expansion and contraction loss of function.
Disadvantages of RTV Silicones
Long Cure Time: RTV is cured slowly and naturally by combining with moisture in the air at room temperature. The curing time is greatly affected by the environment. If the air humidity is low in the environment, the curing speed will be very slow. Of course, if the amount of RTV silicone is large and the coating is thick, the internal curing will be slower. It will take about 24-72 hours to finish curing.
Humidity has a big impact: as mentioned above, curing needs moisture, and if the environment is relatively dry, the curing speed will be very slow or even incomplete. So to cure fast, you need to increase the humidity in the air. But not the greater the better, when more than a certain range, it will make the skin of RTV silicone bubbles, affecting the normal play of its adhesion.
Adhesion is affected by the surface: even though RTV silicone can adhere to the surface of different substrates, but when these surfaces contain oil, dust, etc., it will affect its penetration of the surface voids and grip, adhesion decreased. Therefore, it is necessary to clean the surface to prevent the effect of adhesion is greatly reduced.
Cannot be overloaded: RTV silicone cannot withstand heavy or high pressure structural connections. If it is used on these, it will lose its adhesive properties over time and fall off. Neither can vibration or heavy loads.
Scratch Resistant Surface: Although RTV forms an impermeable film after curing, scratches and holes can easily appear if scratched externally. It is not suitable for places with high friction and frequent use of external forces, and if it must be used, it must be extra protected.
The following is a comparison of the advantages and disadvantages of RTV silicone.
| Property | Advantages | Disadvantages |
| Elasticity & Flexibility | High elasticity; withstands stretching, compression, and bending; good for sealing and shock absorption | May permanently deform under long-term load; not suitable for heavy structural connections |
| Temperature Resistance | Works from -50°C to 250°C; maintains performance at high temperatures | Extreme low temperatures may slow curing and reduce adhesion |
| Adhesion | Good adhesion to metal, glass, plastic, and ceramics | Adhesion can be affected by oily or dirty surfaces; it may need cleaning or primer |
| Waterproof & Sealing | Excellent water and moisture resistance; prevents air leakage | Surface is soft; can be scratched or damaged |
| Chemical Resistance | Resistant to acids, bases, solvents, oils | Limited resistance to strong solvents or certain chemicals |
| Aging Resistance | UV and weather resistant; long-lasting performance | Low-cost products may age faster |
| Ease of Application | Single-component ready to use; two-component easy to mix | Single-component cures slowly; low humidity slows curing; ventilation recommended |
| Environmental & Safety | Low VOC; some products are food-grade or medical-grade | Amino-type may emit a mild odor during curing; it needs ventilation |
| Cost | Excellent performance for demanding applications | More expensive than ordinary sealants |
Types of RTV Silicone
RTV-1: This RTV silicone, no need to mix with other materials, direct use, very convenient. It is very suitable for novice white people to use for daily household repairs. It can also be used for building repairs. It also doesn’t need special equipment, and the effect is still very good. It cures in 24-72 hours.
RTV-2: Here it is made with a mixture of two components. Silicone base and curing agent. It cures much faster than RTV-1 block. It cures completely in minutes and hours. So can you imagine how much of a role the curing agent plays?RTV-2 is suitable for use in scenarios where very short time control is required, such as industrial, mold making. For thicker coatings, a two-component version is suitable, which greatly reduces the curing time. Its adhesion is greater than that of RTV-1, and high intensity scenes can be dealt with.
Below is a comparison table of the properties of these two types.
| Property | RTV-1 (Single Component) | RTV-2 (Two Component) |
| Curing | Air/moisture curing, slower | Mixing two parts, faster and more controllable |
| Ease of Use | Very easy, ready to use | Requires mixing, careful measurement |
| Curing Time | 24–72 hours (thick layers longer) | Minutes to hours, controllable |
| Strength | Moderate | High strength, high elasticity |
| Applications | Household, light sealing, small repairs | Industrial, molds, electronics, automotive |
| Cost | Lower | Higher |
Applications of RTV Silicones
Building & Home
RTV silicones are often found in building construction and home improvement. They are often used to seal windows and doors, fill gaps in curtain walls; waterproof roofs, kitchens and bathrooms. They have moisture-proof characteristics and weather resistance, for indoor and outdoor environmental conditions change, the choice of appropriate RTV silica gel and the design of the formula can be very good performance stability, long-term normal use.
Automotive and machinery
RTV silicone is used in the engine, lights, piping, mechanical equipment of automobiles. The engine uses it as a sealing gasket; the lights use it to seal against dust and water; the piping interface and mechanical equipment use its toughness as anti-vibration protection. These places in the car start, the temperature will rise. And RTV high temperature resistance, aging resistance, grease resistance, can be a good response to the car running environment. If the car has areas that often need repair, it is also very good to use it as a repair tool.
Electronics & Electrical
In this industry, RTV is mainly utilized for its good insulation, waterproof and moisture resistance. It is used as a wind view of circuit boards, protection of sensors, moisture-proofing of connectors, and waterproofing of electronic equipment. Most of the electronic equipment in this field is afraid of water and is prone to leakage, RTV can be a good solution to these two problems at the same time. Can isolate the current, but also can buffer the vibration of the equipment, resistance to chemical corrosion.
Industrial manufacturing and mold
RTV silicone has good fluidity, suitable for making complex shapes of models and parts, but also can stabilize the mold size is highly uniform. And after curing it has good elasticity, in the release of the film, moderate deformation without destroying the mold and the finished product of the pull. These characteristics in this field can be used to make industrial parts, handicrafts, food molds, very suitable for making high precision and durable products.
Medical & Food
Medical device seals, laboratory equipment, and food processing molds can be produced with RTV silicone because RTV silicone has low volatility, low odor, good biocompatibility, and is safe for contact with human skin, and for use in medical treatments. In practice, as a sealing material, it prevents liquids, gases, and contaminants from entering the equipment. It helps medical devices and laboratory equipment maintain cleanliness and performance stability. And, as in industrial manufacturing, it takes advantage of its suitability and high-precision molding properties to maintain consistent dimensions.
Creative Crafts & Crafts
As in industrial manufacturing and the medical and food industries, crafts can be molded with RTV. For example, candle molds, jewelry molds and resin molds are still used because of their high reproduction accuracy, elasticity and easy release properties. These molds are highly compatible and many materials can be poured, like resin, wax, plaster, and cement. Handmade products have high requirements for details, textures and complex shapes, so it can be said that the details determine success or failure, RTV silicone adds a lot of rich elements to handmade products.
RTV Silicone Uses
When you need to choose an RTV silicone that’s right for you, it’s easy to make the mistake of going for the more performance the better. This is not true, you need to choose the right one for you, so from which aspects? First of all, you need to determine your purpose, are you using it for sealing? Or potting? Or mold making? Determine your main purpose, you can choose that type of RTV silicone. Generally used for daily sealing, waterproof, choose RTV-1, if used to make industrial molds, precision replication, thick layer application, choose RTV-2.
After choosing the right type, it is then important to look at a few core performance indicators, including fluidity, strength, temperature range, aging resistance, and so on. These directly affect the molding effect and service life. In the actual construction, what kind of environment will be faced also needs to be considered. Like the temperature and humidity during construction, the structural complexity of the mold or substrate, and whether or not you need to take off the mold quickly. Finally, it also depends on what hardness and curing conditions you need. Follow this order to select a specific formulation of RTV silicone: first confirm the application → choose the right type of RTV → compare the key performance indicators → adjust according to the construction environment → finally confirm the hardness and curing conditions to be durable.
Below is a compilation of what should be taken into account when considering each step, with several tables accordingly:
Table 1: Choose RTV Type First (Step 1)
| Use Scenario | Recommended Choice | Reason |
| Household, on-site sealing, waterproof repair | RTV-1 (Single Component) | Ready to use, simple application |
| Construction, pipes, doors, railings and windows sealing | RTV-1 | Cures with moisture in the air, suitable for on-site use |
| Mold making, industrial production | RTV-2 (Two Component) | Curing time controllable, suitable for thick layers and high precision |
| Requires stable dimensions or mass production | RTV-2 | More consistent curing |
Table 2: Key Performance by Application (Step 2)
| Application Type | Key Performance to Consider |
| Waterproofing and sealing | Adhesion, water resistance, weather resistance |
| High temperature or mechanical environments | High temperature resistance, oil resistance, vibration resistance |
| Electronics and electrical | Insulation, moisture resistance, low corrosion |
| Mold making and replication | Flowability, replication accuracy, demolding performance |
| Medical and food-related | Low volatility, biocompatibility |
Table 3: Selecting Hardness (Step 3)
| Hardness Range | Suitable Scenarios |
| Low hardness (soft) | Complex structures, fine details, easy demolding |
| Medium hardness | General-purpose molds, sealing parts |
| High hardness (hard) | Industrial part molds, high durability required |
Table 4: Consider Construction and Environment (Step 4)
| Usage Condition | Selection Recommendation |
| Low humidity environment | Avoid RTV-1 that relies solely on moisture curing |
| Thick-layer casting | Prefer RTV-2 |
| Fast turnaround required | Choose formulations with controllable curing time |
| Long-term outdoor use | Pay attention to UV and aging resistance |
Table 5: Special Application Considerations (Step 5)
| Application | Things to Consider |
| Electronic devices | Low corrosion, insulation rating |
| Medical or food-related | Safety grade, compatible formulation |
| Chemical environments | Chemical resistance, easy cleaning |
FAQ
What is the Difference Between RTV Silicone and Other Types of Silicone?
The biggest difference between them is the curing method, RTV does not need to be heated, just need to be left at room temperature to cure successfully. High-temperature silicone, curing silicone requires high-temperature heating to cure. Liquid silicone and the previous two types of similar process logic, heat can accelerate the curing. rtv want to speed up the curing speed, you have to improve the air humidity or add crosslinking agent in its formula to help accelerate the curing.
How to Choose the Right RTV Silicone for Home Repairs?
Don’t just look at the parameter table, you have to look at the site conditions. If you want to seal and waterproof doors, windows, sinks and pipes, choose RTV-1. It is easy to operate and requires no other equipment or materials. Waiting 1-3 days, it can be cured. If you want to use it for small molds and to speed up the curing time, then you should use RTV-2, which cures much faster than RTV-1. It cures faster, increases your efficiency and saves time.
How Long Does RTV Silicone Take to Cure?
RTV needs to be stored carefully, it is very sensitive to environmental conditions. rtv silicone will slowly cure when it encounters air, so it should be stored in a sealed container. Opened ones must be sealed immediately. It should be stored in a dry and cool place at a suitable temperature of 5-25℃. Because high temperature will speed up the cross-linking reaction and shorten the life, low temperature will reduce the performance. You also can’t let direct sunlight, the material will also aging.
Can RTV Silicone Be Used in High Humidity Environments?
Yes, and in many cases, high humidity will it even better. High humidity allows RTV silicone to fully react with moisture in the air, speeding up curing. In humid environments such as bathrooms, kitchens, and basements, RTV silicone cures faster. However, when the thickness is high, the surface quickly forms a skin, and the interior can not come into contact with the air, but the curing speed slows down.
Final Thought
RTV silicone is very useful, to here, I think you have a comprehensive understanding of the properties and uses of RTV silicone. You should also understand how to choose the right RTV silicone for you, and not only look at the number of RTV properties, choose the best for your needs.
Legensilicone has been developing and manufacturing RTV silicone for a very long time. We care about how the material performs in the real world, and we design solutions that are tailored to the needs of our customers. Whether you are looking for everyday sealing, crafts, industrial manufacturing, etc., we can design an RTV silicone that will fit your needs and application, guaranteeing consistent performance and a long service life. If you want to find a real understanding of the material, understanding of the application of the manufacturer to cooperate, come to us, look forward to a happy cooperation!
