MIL-PRF-23236 Coating Systems For Ship StructuresThis specification covers four types of air pollution regulated ship and structure coatings that comply with the National Emission Standards for Hazardous Air Pollutants \(NESHAP\) for shipbuilding for state and federal regulations. There are nine classes of coating systems. There are four grades of coating systems based on temperature of application and cure. In addition to tanks, all paint systems qualified to this specification are suitable for use on any ship structures, interior or exterior, for corrosion control. Except for trace levels, all types are free of lead, chromium, cadmium, and asbestos \(see 3.2.3\). All types have levels of hazardous air pollutants \(HAPs\) that do not exceed applicable NESHAP levels \(see 3.2.2.2\). Dry Type V, VI, VII, and VIII coating residues and debris are non-hazardous waste under U.S. Environmental Protection Agency \(USEPA\) regulations in effect on the date of this specification. Type VII coating will not have any solvent added to either the base resin component or the hardener component.

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MIL-PRF-23236D

APPENDIX A

EDGE RETENTION TEST

A.1 SCOPE

A.1.1 Scope. This appendix provides the test method procedure referenced in 4.5.9 of this specification for

compliance with 3.8.1 of this specification. This appendix is a mandatory part of the specification. The information

contained herein is intended for compliance.

A.2 Edge retention sample preparation.

A.2.1 Specimen preparation. The edge retention specimen should use an Aluminum Alloy 6061 structural

angle (90-degree) section approximately 6 inches long. Preparation of the specimen for test will require three basic

steps: sample machining to meet initial dimension requirements, grit blasting to provide acceptable anchor tooth,

and surface cleaning prior to coatings application. Procedures for preparation are as follows:

A.2.1.1 Sample machining. Both exterior surfaces should be milled so that faces are square (90�0.1 degrees)

and have a surface finish of 63 micro-inches. The exterior edge should be left as a "sharp" edge with no radius

tolerance or chamfer.

A.2.1.2 Grit blasting. Specimen should be grit blasted using Al2O3 media to achieve an anchor tooth profile of

1-3 mils. Care should be taken to minimize rounding of the edge with excess blasting. Final edge radius should not

exceed 0.04 inch (�10 percent).

A.2.1.3 Cleaning. Specimen should be cleaned thoroughly with acetone or appropriate solvent to remove all

traces of grease prior to abrasive blasting and coating application.

A.2.3 Paint application. Topcoat is then spray applied to unprimed metal, maintaining correct pump pressure

and distance from substrate (approximately 18 inches) according to manufacturer's recommendations. Paint is

applied to both sides (first) and the edge (last) within 1 minute. Measure the wet film thickness on the flat sides to

ensure compliance with minimum recommended film thickness. After paint application, cure the specimens at

ambient laboratory conditions for a minimum of 72 hours before sectioning (see Figure 5).