Overview
Test and Evaluation of Primers with Extended Anti-Fouling (AF) Overcoat Windows (2019-480-001)
Project Team:
- Excet, Inc.
- PPG Paint
- Sherwin Williams
- International Paint
- BAE Systems ā JSR
- HII-Ingalls
- GD-Bath Iron Works
- Naval Research Laboratory
2019
NSRP ASE INVESTMENT: $150K
Objective:
The goal of this project was to evaluate epoxy ātie coatsā that are compatible with MIL-PRF-24647 antifouling (AF) topcoats. AF coatings are qualified as a system to MIL-PRF-24647, Type II (copper ablative), Class 1 (steel surfaces), and Grade A (340 g/L), B (250 g/L), or C (100 g/L). The ablative anti-fouling coatings are applied over two coats of anticorrosive primer in accordance with the requirements of NAVSEA Standard Item 009-32 FY-18 (CH-1), Table One, Lines 1-5.Ā Ā The installation process is to apply the first coat of ablative antifouling when the second coat of primer is soft and touch tacky (i.e., a fingertip pressed lightly, without twisting, against the paint film leaves no residue on the finger, finger leaves a slight impression on the surface of the paint film) to promote good inter-coat adhesion between the AF and primer. Because the primers harden rapidly when warm, the “overcoat window” for applying the ablative antifouling can be short and improperly judging the touch tacky period has historically led to premature, in-service delamination of the ablative topcoat from the primer. Ideally, the epoxy ātie coatsā will have an extended overcoat window (up to 3 days) before the first coat of AF must be applied and still have acceptable adhesion. Extending the overcoat window, even if for only a couple days, will provide dry dock managers greater schedule flexibility and reduce costly rework.
Key Deliverables
Contact NSRP for the final report: Distribution authorized for the U.S. Shipbuilding and Repair Industry