SAE AMS 8660 Silicone Compound NATO Code Number S-736

The standard "SAE AMS 8660 Silicone Compound, NATO Code Number S-736," developed by the Society of Automotive Engineers (SAE), specifies a type of non-melting, heat-resistant silicone compound for application to unpainted mating threaded or non-threaded surfaces in high-voltage electrical connections, ignition systems, and electronic equipment, and as a lubricant for rubber components. This compound is effective for extended periods in the temperature range of -54°C to +204°C. This compound is identified by the NATO symbol S-736.

This standard specifies a type of non-melting, heat-resistant silicone compound for use in high-voltage electrical connections, ignition systems, and electrical applications. The silicone compound provided under this standard must be eligible for listing on the current qualified product list at the time of the bid opening. The materials used in the formulation of the silicone compound must be of high quality and suitable for the intended use. The final product should be a smooth, lump-free, grease-like compound.

In terms of toxicity, the material must not have an adverse effect on personnel health when used for its intended purpose. Questions regarding this effect should be referred by the contracting activity to the appropriate departmental health service, which will act as an advisor to the contracting agency.

The compound should be naturally translucent and have a light gray or cream-like color. A dye or pigment may be added to the material, if specified, provided the finished compound meets the requirements of this specification in all other respects.

The performance characteristics are determined as follows:

• Physical properties: The physical properties of the silicone compound must comply with the requirements in the table given in the standard.
• Watertight seal: When tested as specified in this standard, test paper discs shall show no pink coloration in 3 out of 5 tests. Any color change within 3 mm of the edge of the test discs shall be disregarded.
• Electrical properties: The electrical properties of the silicone compound must comply with the table given in the standard.
• Storage stability: After 6 months storage at 38 degrees plus/minus 3 degrees as specified in this standard, the untreated and treated penetration of the compound shall comply with the requirement in the table at 25 degrees plus/minus 1 degree.
• Workmanship: The compound must be worked to produce a homogeneous mixture free from lumps, cakes, abrasives and foreign matter.

Unless otherwise specified in the contract or purchase order, the contractor is responsible for fulfilling all inspection requirements specified herein. Unless otherwise specified in the contract or purchase order, the contractor may use its own or other suitable facilities to perform the inspection requirements specified herein, unless legally approved. Regulatory authorities reserve the right to conduct any of the inspections specified in the specifications as deemed necessary to ensure that supplies and services comply with the required requirements.

The audit requirements specified here are classified as follows:

• Quality control

This audit consists of all the requirements and tests specified in the tables.

Two copies of the manufacturer's test report, containing complete test data demonstrating that the material submitted for qualification complies with the requirements of this standard, must be submitted with the qualification sample. The location and identification of the facility that produced the tested sample must also be provided. Material safety data sheets for toxicity must be prepared in accordance with FED-STD-313 and submitted to the qualification laboratory.

To maintain the qualification of a product approved for listing on the qualified product list, the manufacturer must verify that the manufacturer's product complies with the requirements of this specification by providing certification to a qualified activity. Periodic verification with certification must be at two-year intervals from the original qualification date. Regulatory authorities reserve the right to re-inspect the qualified product as deemed necessary to determine that the product continues to meet any or all of the specification requirements.

• Quality conformity audit

Unless otherwise specified herein or in the contract, a batch shall be all silicone compound manufactured as a single batch, part of a single contract or order, and submitted for inspection at one time.

When sampling for testing, two approximately 2,3 kg samples of silicone compound are randomly selected from each lot and tested as specified herein.

When sampling for packaging, a random sample of containers filled in accordance with MIL-STD-105 is selected from each batch and examined as specified therein. The batch size shall be the total number of unit containers.

Shipping containers are randomly selected from each lot immediately prior to warranty service in accordance with MIL-STD-105 and inspected as specified therein. The lot size shall be the total number of shipping containers.

The selected sample is tested batch-by-batch according to the requirements in the table, or once every ten batches as specified in this table. Failure of a test sample to meet a single requirement in the table shall be grounds for rejection of the batch represented by the sample. If a failure occurs in one of the ten batches during an examination, regulatory authorities may, at their discretion, require testing of each subsequent batch.

This level of standardization is crucial in aerospace and defense applications, where material failures can have catastrophic consequences. Therefore, the key reasons for this standard are:

• Guaranteed high-temperature stability and non-melting behavior: This standard ensures that electrical connections and other critical assemblies maintain their integrity in both arctic and high-heat environments.
• Reliable electrical insulation and corrosion protection: The compound provides excellent dielectric strength and water repellency, preventing moisture ingress that could lead to galvanic corrosion or electric arcing in high-voltage connections and ignition systems. This is crucial for ensuring the uninterrupted operation of avionics electronics, relays, switches, and other sensitive components.
• Consistent quality with a qualified product listing: Manufacturers wishing to supply compliant compounds must undergo qualification testing and be listed. This protects against variability among suppliers and simplifies the procurement process; maintenance teams know exactly which approved materials to order; and OEMs can trust that performance will not vary from batch to batch.
• Ease of application and maintenance: By remaining soft and semi-fluid, SAE AMS 8660 silicone compound facilitates easy assembly, disassembly, and rework of threaded or non-threaded interfaces without damaging mating surfaces. It also acts as a lubricant for rubber components, further simplifying field repair procedures.

In safety-critical industries like aerospace, compliance with this standard is not just a recommendation, it's a requirement. It ensures that components based on this silicone compound will perform predictably throughout their service life across the full spectrum of environmental stresses encountered in flight and ground support operations.

S in NATO's coding system-736 is a non-melting, heat-resistant silicone sealant used to moisture-proof and insulate high-voltage electrical connections, ignition systems and electronic assemblies.

Our organization, which has been supporting businesses across all sectors for years through a wide range of testing, measurement, analysis, and evaluation activities, has a strong team of employees who closely follow global developments in science and technology and are constantly improving themselves. In this context, we also provide testing services to businesses in accordance with the "SAE AMS 8660 Silicone Compound NATO Code Number S-736" standard.