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SAE J400 Gravel Bombardment TestingSAE J400 Chip Resistance Testing

SAE J400 determines the resistance of a surface coating to chipping by gravel impact. As an ISO-17025 accredited environmental compliance test lab, we realize the importance of gravel bombardment and chip testing.

Meeting the SAE J400 environmental requirements can be difficult. We understand the challenges and guide companies through the process. 

Keystone Compliance partners with customers to achieve environmental product compliance. We offer competitive pricing and volume discounts. When products do not meet the specified requirements, Keystone assists with the troubleshooting process. 

Request a quote and find out first hand about our competitive pricing, timely process, and outstanding reputation. Ready to get started? We are. Contact us to see why so many companies work with Keystone each year to achieve their environmental standard test needs.

Summary of SAE J400 Gravel Bombardment Compliance Testing

SAE J400 testing evaluates the resistance of a surface coating to chipping. More specifically, chipping by gravel impact. The test is designed to reproduce the effect of gravel striking exposed paint or coated surfaces of an automobile.

SAE J400 Chip Resistance Compliance Testing Procedures

It is recommended that three replicates of each test specimen be used. The specimen size is typically flat 10 x 30 cm in size.

This test consists of projecting road gravel using a controlled air blast onto a suitable test panel. Before testing, the specimen must reach ambient temperatures for a minimum of 15 minutes.

Gravel for this test must be water-worn road gravel. Not crushed limestone or rock. Also, the gravel must pass through a 15.86mm space screen when graded. The gravel must also be washed before testing.

During the gravel exposure, no more than 10 pt of gravel is allowed to collect on the sizing screen. Once 10pt is collected, the smaller rocks are scraped across the screen to remove them. 

After the gravel impact, tape is applied to remove any loose paint chips on the panel.

There are two methods of determining the degree of chipping. Method I tabulates the exact number of chips in each size range. Method II visually compares the tested panel with the SAE chipping rating standard.

Lastly, after testing, a report includes the rating and all applicable test conditions used. The report will also include the test results, material type, thickness, and any preliminary surface treatment of the test panel.

Expert SAE J400 Regulatory Compliance Testing Facility

Keystone has a full lab of test equipment which permits us to provide short lead times on scheduling. In addition to environmental gravel bombardment testing, Keystone has a full scope of expertise including ingress protection, altitude, and fungus

Request a quote to receive testing services tailored to your specific requirements.