Momentive RTV 157 Silicone Sealant User Manual

1. Introduction

The Momentive RTV 157 is a high-strength, one-part silicone sealant designed to cure into a tough, durable, and resilient silicone rubber upon exposure to atmospheric moisture at room temperature. This product features a high-strength paste consistency, making it suitable for application on vertical and overhead surfaces where pourable or self-leveling sealants are impractical. It offers excellent performance across a wide temperature range, from -75°F to 400°F.

This manual provides essential information for the safe and effective use of the Momentive RTV 157 silicone sealant, including product features, safety precautions, application instructions, maintenance, and specifications.

Figure 1: Momentive RTV 157 Gray Silicone Sealant 2.8 Ounce Tube. This image displays the product packaging, a gray tube labeled 'RTV 157 Gray Adhesive' and 'Aerospace Grade High Strength', with a clear nozzle cap. The tube indicates a volume of 2.8 fl. oz. (82.8 ml).

2. Product Features

• One-part, high-strength RTV silicone sealant, gray in color.
• Suitable for applications such as high voltage wire and cables, valve sealants, fluid metering devices, gaskets, and sealing devices.
• Offers primerless adhesion to many metals, plastics, and glass surfaces.
• Features a high-strength paste consistency for versatile application.
• Provides excellent weatherability, ozone resistance, and chemical resistance.

3. Safety Information

WARNING: UNCURED PRODUCT CONTACT IRRITATES EYES. Read back carefully.

Always ensure adequate ventilation when using this product. Avoid direct contact with skin and eyes. In case of contact, flush affected areas with water immediately and seek medical attention if irritation persists. Keep out of reach of children and pets. Refer to the Safety Data Sheet (SDS) for complete safety information.

4. Setup and Preparation

1. Surface Preparation: For optimal adhesion, surfaces must be clean, dry, and free of oil, grease, dust, and other contaminants. Solvent cleaning may be necessary for some substrates.
2. Ventilation: Ensure the work area is well-ventilated to allow for proper curing and to disperse any vapors.
3. Tooling: Prepare any necessary tools such as a caulk gun (if applicable for larger cartridges, though this is a tube), spatulas, or smoothing tools.
4. Nozzle Preparation: Cut the nozzle tip to the desired bead size at a 45-degree angle.

5. Operating Instructions

1. Application: Apply the sealant in a continuous, even bead to the prepared surface. For bonding applications, apply to one surface and quickly mate the two surfaces together.
2. Tooling (Optional): If necessary, tool the sealant bead immediately after application to achieve a smooth finish and ensure good contact with the substrate. Use a clean, dry tool or a tool dampened with a compatible solvent if recommended by the manufacturer (check SDS).
3. Curing: The sealant begins to cure upon exposure to atmospheric moisture. Skin-over time and full cure time will vary depending on humidity, temperature, and bead thickness. Refer to specifications for typical curing rates.

6. Maintenance

• Cleanup: Uncured sealant can be cleaned from tools and surfaces using a suitable solvent. Cured sealant must be removed mechanically (e.g., by cutting or scraping).
• Storage: Store the product in its original, tightly sealed container in a cool, dry place away from direct sunlight and moisture. Ensure the cap is securely replaced after each use to prevent premature curing.
• Shelf Life: Adhere to the manufacturer's recommended shelf life for optimal performance.

7. Troubleshooting

• Poor Adhesion: Ensure surfaces were properly cleaned and dried before application. Verify that the sealant is compatible with the substrate material. Consider using a primer if adhesion remains an issue, though this product is designed for primerless adhesion to many materials.
• Slow Curing: Low humidity or low temperatures can slow down the curing process. Ensure adequate ventilation and ambient moisture. Thicker beads will also take longer to cure.
• Sealant Not Dispensing: Check if the nozzle is clogged or if the sealant has cured inside the tube. Ensure the tube is not expired.

8. Specifications

9. Warranty and Support

For specific warranty information or technical support regarding the Momentive RTV 157 silicone sealant, please refer to the official Momentive website or contact their customer service directly. Product documentation, including Safety Data Sheets (SDS) and technical data sheets, can typically be found on the manufacturer's website.

Contact information for Momentive can usually be found on the product packaging or their official corporate website.