Exterior Trim Paint on Chrome
|Publication Date:||1 September 2021|
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.
This standard contains requirements of coatings that are intended to be used for painting over chrome plated surfaces for exterior automotive trim components. This includes paints that are transparent or tinted, as well as low-gloss opaque, i.e., non-transparent paints. This standard also details the requirements for approval of the entire combination of chrome plating process, pretreatment, paint, and painting process in the production setting.
Paint systems used to paint on chrome are typically Two-Component (2K) monocoat or 2K base tint color clear coat. These paint systems can also use primers or other pretreatments to improve adhesion to chrome to meet performance requirements. Paints in other chemical classes may also apply to this specification. This specification does not cover painting with resist coats used on chrome plated parts as black out or other decorative schemes. For resist painting on chrome plated parts, refer to specification 9984255. Table 1 describes paint on chrome application information by type.
This specification can apply to painting on chrome for any base substrate. Examples are plastics and various metals used to make chrome plated decorative parts. Refer to specifications for decorative chrome plating to specific substrate specifications, e.g., GMW14668 for chrome plated plastics. This type of coating is used to enhance the appearance of chrome plating. Typical applications include exterior trim parts, such as grilles and door handles.
Each combination of chrome plating process, pretreatment, paint, and painting process shall be tested and approved to this specification as a system. The individual components are not interchangeable. In addition, the paint system is part of the total painted product system and shall meet qualifications set forth in this specification and those shown on GM Engineering Drawings.