GMW GMW18478 PDF

Note: Nothing in this standard supercedes applicable laws and regulations.

Note: In the event of conflict between the English and domestic language, the English language shall take precedence.

Purpose/Material Description.

Material candidates for this specification should either improve the stiffness of body panels, reduce noise and vibration, or serve a dual purpose as a stiffener and damper. The pumpable or sprayable material will be applied in the body shop robotically to oiled automotive substrates, including but not limited to cold rolled steel, electro-galvanized, hot dip galvanized steel, and aluminum substrates, coated with production processing oils. The material shall withstand production paint process of Alkaline Hot Cleaning Solution dip, Phosphate/Zirconium dip and Electrodeposition Primer Operation (ELPO) dip operations without sagging, sliding, or washing away from the original placement. The material shall also be compatible and cure within the production ELPO, primer/surface and topcoat bake operations exhibiting temperatures up to 190 °C.

Symbols.

Not applicable.

Applicability.

Materials approved to this specification will be applied to exterior body panels, hoods, and roofs as a replacement for manual patches. Depending on the material classification, the adhesive will provide additional stiffness to improve resistance to “oil canning” and/or be an acoustic barrier to reduce noise in the interior cabin.

Remarks.

This specification describes different types of materials with types D, S, and H.

Damping materials will be specified by denoting “D” after the material callout with the associated classification per Table 6. Testing according to 3.3.7 and 3.4.2. is not necessary and can be omitted.

Stiffening materials will be specified by denoting “S”. Testing according to 3.5 is not necessary and can be omitted.

Hybrid materials will be specified by denoting “H” after the material callout with the associated damping classification per Table 6. All testing shall be completed.

Classification.

The materials shall be classified by material type (D, S and H) and by performance levels of composite Loss Factor (Table 6) when applicable as described in Table 1.

See Section 8 for the coding system guidelines.