Many friends ask when choosing paint or coating: "How good is the protection effect of this paint? Is it scratch-resistant? Impact-resistant?"
Reading the manual alone is not enough. Today, we take you into a professional coating production factory laboratory to reveal the truth through a hardcore "survival challenge" — Gravelometer Test.
What is the gravel impact test?
Simply put, this test simulates the real-world scenario of gravel and stones splashed from the road surface impacting the vehicle body or object surface at high speed during daily driving. If a coating cannot even withstand the impact of small stones, there is no basis to talk about its protection of the substrate.
Lab Test Live: The "Baptism" of 3 kg of Sand Grains
At the laboratory site, the testing personnel operated with rigor and professionalism:
- Prepare "ammunition": The inspector pours 3 kg of sand grains of varying coarseness into the gravel impact tester. These are not ordinary sand, but particles simulating the real proportions found in natural environments.
- Fixed sample: Firmly fix the painted metal sample at the impact opening, ensuring that the coated side faces the impact direction. This concentrates the force to test the performance of the same area under dense impacts.
- Initiate impact: The moment the valve opens, all the sand and gravel pour out like flowing water, bombarding the coating surface at high speed. According to different industrial standards, multiple repeated tests may sometimes be required.
Result determination: the devil is in the details.
After the impact test concludes, the tester will conduct a detailed evaluation:
- Visual observation: Observe whether there is any cracking, spalling, or peeling at the impact point.
- Tape peel test: This is a more professional evaluation step. The inspector will use a special tape to stick it on the damaged area and pull it off forcefully, in order to test the bonding strength between the coating and the metal surface.
Summary
If the damaged area is extremely small, or only leaves a slight dent without breaking, it indicates that this coating has excellent toughness and extremely strong adhesion. Only paint that has passed this kind of "brutal test" can provide long-lasting and stable protection for your products.