Chipping Resistance Testing

Chipping resistance testing evaluates two things simultaneously: whether the addition of Gentoo changes the initial chip resistance of the underlying paint system, and whether Gentoo provides improved corrosion protection following chip damage compared to the uncoated control.

Test Protocol — ASTM D3170

Chipping resistance testing was performed per ASTM D3170 Standard Test Method for Chipping Resistance of Coatings. Cured, coated panels were tested in triplicate. Each panel was mounted in the target chamber of a Gravelometer and fired with one pint of 3/8–5/8 inch water-eroded alluvial stones using an air gun operating at 70 psi. Loose gravel was removed from the panel using filament tape, and the panel was rated by visual comparison to transparent standard chips.

Testing was conducted on the following panel configurations:

• Bare LHE Zn-Ni plated 4130 HSS steel panels: Untreated control and Gentoo treated.
• Primed and topcoated LHE Zn-Ni plated 4130 HSS steel panels: MIL-PRF-23377 epoxy primer with MIL-PRF-85285D grey urethane topcoat — untreated control and Gentoo treated.
• Second panel set: LHE Zn-Ni 4130 HSS with MIL-PRF-23377J Type I Class N chrome-free epoxy primer and MIL-PRF-85285 Type I Class H white gloss urethane topcoat — with and without Gentoo. Bare LHE Zn-Ni 4130 with and without Gentoo also included.

Chipping Resistance Results

No reportable differences were observed in chip protection ratings between Gentoo-treated and untreated panels across all panel configurations. This result is important and expected: Gentoo, at 4–6 µm, does not meaningfully alter the mechanical chip resistance of the underlying paint system. Gentoo's role is protective barrier enhancement — not chip prevention — and this result confirms the coating does not compromise the chip resistance of the system it is applied over.

Post-Chip Salt Fog Corrosion Results — 2,000+ Hour ASTM B117

Following chipping resistance testing, the damaged panels were placed into an ASTM B117 salt fog chamber. This is the critical comparative assessment — how does Gentoo perform in protecting the surrounding coating from corrosion after the surface has sustained mechanical chip damage?

After 2,136 hours of ASTM B117 salt fog exposure, Gentoo-treated steel panels and Gentoo-treated primed/topcoated steel panels showed significant corrosion improvement over the bare steel and painted steel control panels. The Gentoo treatment provided added exposure protection as a function of impact damage over the control panels — meaning that even after mechanical chipping, Gentoo continued to provide meaningful additional corrosion protection from the surrounding intact film.

Testing was repeated on a second panel set. After 2,000 hours of ASTM B117 salt fog, red rust spots were visible on the painted control panels. The Gentoo-treated panels remained unchanged — no red rust visible.