ASI Clear Electronic Grade Silicone 388 Instruction Manual

1. Introduction

This manual provides detailed instructions for the proper use, application, and storage of ASI Clear Electronic Grade Silicone 388. This product is a one-part, moisture-curing RTV (room temperature vulcanizing) silicone sealant/adhesive designed to form a tough, permanently flexible rubber. Its non-corrosive curing system makes it ideally suited for protecting, sealing, and insulating corrosion-sensitive electronic and electrical materials.

Image 1: ASI Clear Electronic Grade Silicone 388 in a 10.2 oz cartridge.

Key Features:

• One-part, moisture-curing RTV silicone sealant/adhesive.
• Non-slump, cures to form a tough, permanently flexible rubber.
• Non-corrosive curing system, suitable for corrosion-sensitive electronic and electrical materials such as copper, brass, and silver.
• Specifically formulated for electrical/electronic production and assembly.
• Neutral-cure silicone that emits no objectionable odors.
• Excellent resistance to temperature changes from -57°C to +204°C (-70°F to +400°F).
• Good Dielectric Properties and resists electrical tracking.
• Repels water to protect electrical properties.
• Adheres to various substrates.
• Low odor and does not corrode by outgassing.

Additional Benefits:

• Contains no solvents or isocyanates, making it VOC compliant.
• UL Approved for Horizontal Burn and Mechanical Adhesion.
• Fast tack-free time.

2. Product Overview

Common Applications:

ASI 388 is an excellent sealant and adhesive for a wide range of industrial, commercial, and OEM applications where a long-term, permanently flexible bond or seal is required. Typical applications include:

• Circuit board protection and electrical encapsulating.
• Sealing lead wire entries, component mounting, and electrical connections.
• Waterproofing electronics and adhering electronic components.
• Sealing and bonding electronics, engine components.
• Telecommunications, including coaxial cable connectors.
• Conduit terminal boxes, conductor entry holes, splices, and cover plates.
• Printed circuit boards.

Common Bonding Substrates:

ASI 388 can be used on a variety of substrates. It is recommended to test adhesion on specific substrates before full application. Common substrates include:

• Aluminum, steel, and other metals.
• Porous substrates such as concrete, mortar, and brick.
• Glass, rubber, and most woods.
• Most plastics, porcelain, PVC, and vinyl.

3. Setup and Surface Preparation

Surface Preparation:

For optimal adhesion, all surfaces must be clean and dry. If necessary, bonding surfaces can be solvent wiped with naphthas, ketones, or chlorinated solvents. Specific solvents include xylol, toluol, and mineral spirits. For plastics, determine solvent suitability prior to use. Allow surfaces to dry thoroughly before applying sealant. Avoid solvent wiping with alcohols or oil-containing solvents like Varsol.

Priming for ASI 388 is generally not required for applications on non-porous surfaces. If unsure about adhesion, a small trial bead can be applied and allowed 7 days to cure for testing. Contact ASI if a primer is required.

4. Operating Instructions and Application

Application:

ASI 388 is ready to use and requires no mixing. The cure mechanism begins as soon as the sealant contacts air. At 25°C (77°F) and 50% relative humidity, the sealant will skin in 10-20 minutes and cure in 24 hours (for a 1/8" bead), reaching maximum adhesion in 7 days. Higher humidity accelerates curing.

If tooling is necessary, it should be completed before a skin forms. In applications where the sealant is partially or totally confined, the time required for proper cure may be extended.

Cure Time:

• Tack-Free Time: 10-20 minutes
• Full Cure Time (1/8" bead): 24 hours
• Full Adhesion Strength: 7 days

5. Safety Precautions

On direct contact, uncured sealant may irritate eyes. Flush eyes thoroughly with water and seek medical attention from a physician. Avoid prolonged contact with skin. Adequate ventilation should be provided, especially when used in large-scale production or confined areas.

6. Storage

When stored in original, unopened containers at or below 32°C (90°F), ASI 388 has a shelf life of 12 months from the date of shipment.

7. Specifications

Image 2: ASI 388 Electronic Grade Silicone Product Data Sheet.

General Product Information:

• Brand: Generic
• Model: ASI001
• Container Type: Cartridge
• Volume: 10.2 Fluid Ounces
• Color: Clear (also available in black and white; special colors upon request)
• Material Type: 100% Silicone
• Viscosity: Medium to High Viscosity
• Temperature Resistance: -57°C to +204°C (-70°F to +400°F)
• Special Features: Electrical Resistance, Non-Corrosive
• Compatible Materials: Copper, Brass, Silver, Metal, Glass, Plastics, Wood, etc.
• Included Components: Nozzle

Listed Properties:

Packaging:

ASI 388 is supplied in 10.2 fl. oz. caulking cartridges, 440 lb. pails, and 44 lb. drums. Special packaging options may be available upon request.

Military Specifications:

ASI 388 meets the requirements of MIL 46106 Type 1.

8. Maintenance and Troubleshooting

This product is a sealant/adhesive and typically does not require maintenance after proper application and curing. If the seal is compromised or requires replacement, the old sealant should be removed, and the surface prepared as per Section 3 before reapplication.

Troubleshooting for this product primarily involves ensuring proper surface preparation and application conditions. If the sealant does not cure or adhere as expected, verify that surfaces were clean and dry, and that environmental conditions (temperature, humidity) were within recommended ranges. Ensure the product has not exceeded its shelf life.

9. Warranty Information

ASI warrants only that its products will meet its specifications. ASI shall in no event be liable for incidental or consequential damages. Except as expressly stipulated, ASI's liability, if any, shall be limited to a refund to the stated selling price of any defective goods.

10. Support and Contact Information

Information on this data sheet can change without notice and is not recommended for use in specification writing. For any questions or technical support, please contact the manufacturer.

Manufacturer: ASI (American Sealants, Inc.)
Address: 3806 Option Pass, Fort Wayne, Indiana 46818
Website: www.americansealantsinc.com
Phone: 1-800-325-7040