GMNA 9984187 PDF

This specification details the requirements of a sealer material that is tacky for adhesion to metal, and will expand at high bake conditions. The sealer may be formed into a part that is attached to a body panel at a subassembly source or in the assembly plant body shop, prior to the assembly plant paint shop. The material expands and cures in the paint shop electrocoat oven. The material is intended to seal interior and exterior body joints against water, dust, and air intrusion.

Parts constructed with high expanding versions of these sealers are referred to as baffles, and are used to fill cross sections in body cavities and reduce airborne noise.

Material Description. Materials approved to this standard are tacky on one (1) side. Tacky sealer materials, formed into parts, are applied directly to oily metal. They must remain in position in the uncured state up to and throughout the pretreatment and electrocoat processes.

The sealer material must adhere to production oily metal, such as cold rolled steel (CRS), hot dipped galvanized metal/electrocoat (HDG/ELPO) substrates and other (i.e., aluminum (AL)), as specified by the requesting GM Engineer.

The sealer material must not accelerate rusting of the metal steel over which it is applied.

Symbols. Not applicable

Applicability. These materials are typically applied manually, in the body shop. These materials are not intended to be weldable or fuel resistant, or applied in the paint shop.

Remarks.

Technology Approval Documentation. At the conclusion of testing to this specification, the supplier must provide a document package per 1.4.1.1 and 1.4.1.2.

Product Data. Documentation of all attributes and test results, per Section 3 and Section 4 of this specification. All test panels should be detail identified and photographed for full documentation. Additional information may be requested by the responsible GM Engineer, including manufacturing site and, trend charting of these attributes over an extended period of production material runs.

Bake Charts. Provide bake window charts that identify the Bake conditions where the sealer does meet and no longer meets, requirements. Key Product Characteristics to include at minimum: Volumetric Expansion and Initial Adhesion. The chart is to reflect:

• Time at metal temperature on x-axis (minimum range: 0 minutes to 90 minutes).

• Temperature on y-axis (minimum range: 150 °C to 205 °C).