SAE J400:2002 pdf download

SAE J400:2002 pdf download Test for Chip Resistance of Surface Coatings
1. Scope—This SAE Recommended Practice covers a laboratory procedure for testing and evaluating the resistance of surface coating to chipping by gravel impact. The test is designed to reproduce the effect of gravel or other media striking exposed paint or coated surfaces of an automobile and has been correlated with actual field results. The specific intent of the test is to evaluate organic surface coatings or systems on flat test panels; however, It may be possible to extend this type of testing to finished parts or other types of materials such as anodized aluminum or plated plastics if the results are interpreted with respect to the limitations and intent implied by the original testing procedures and rating system.
This document may involve hazardous materials, operations, and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of whoever uses this document to consult and establish safety and health practices and determine the applicability of regulatory limitations prior to use.
All dimensions are nominal unless otherwise noted.
2. Reference
2.1 Related Publication—The following publication is provided for information purposes only and is not a required part of this document.
2.1.1 SAE P UBLICATION —Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.
SAE 680046—Measurement of Chipping of Organic Coatings for Automobiles, John T. Young and Donald R. Hays, Ford Motor Co., Indust. and Chemical Products Div., Warrendale, PA, USA, Society of
Automotive Engineers, Inc., 1968
3. Summary of Method—The test consists of projecting standardized road gravel by means of a controlled air blast onto a suitable test panel. The testing apparatus is called a gravelometer, designed to contain road gravel, a test panel holder, and a gravel projecting mechanism. The projecting mechanism, located in front of the test panel, consists of an air nozzle in the base of an inverted pipe tee. The stem of the pipe tee points upward and is located beneath a vibrating hopper into which the gravel is poured. The gravel, falling into the air blast, is projected toward and impacts upon the test panel, which is usually held perpendicular to the impinging gravel. All testing is conducted under controlled temperature conditions, generally room temperature (ambient) or –29 °C ± 3 °C (–20 °F ± 5 °F). After the gravel impact, tape is applied to remove any loose paint chips remaining on the panel, and the degree of chipping is determined by visual comparison with the SAE Chipping Rating Standards 1 , by counting the number and sizes of all chips, or by other methods deemed suitable between the contractual parties involved.