GMNA 9984188 PDF

This specification details the requirements of a sealer material that is Non-Tacky and will expand in a High Bake oven. 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 (E-Coat) 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 known as baffles, which are used to fill cross sections in body cavities to reduce airborne noise.

Material Description.

Materials approved to this standard are also Non-Tacky.

Non-Tacky sealer materials generally require a carrier or fastener, to hold them in place in the uncured state, up to and throughout the paint shop pretreatment and E-Coat processes. Parts made from these materials have an optimum design for corrosion avoidance when they allow sufficient clearance between the uncured part and the adjacent metal to enable E-Coat coverage behind the part.

The sealer material must adhere to production oily metal, including cold rolled steel (CRS), galvanized metal, i.e., hot dipped galvanized/electrogalvanized (HDG/EG), E-Coated 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.

Technology Approval Documentation.

At the conclusion of testing to this specification, the Supplier must provide a document package per 1.4.1 and 1.4.2.

Product Data.

• Documentation of all attributes and test results, per Section 3 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 for a number 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). Additional direction to be provided by the approving material engineer.