The MIL-PRF-23377 performance specification covers the requirements for corrosion inhibiting, chemical and solvent resistant, solvent-borne, high-solids epoxy primer coatings that have a maximum volatile organic compound (VOC) content of 340 grams per liter (g/L)(2.8 pounds per gallon [lb/gal]) as supplied by the manufacturer. This specification is approved for use by all Departments and Agencies of the Department of Defense.
Composition: The primer coatings shall consist of two or three components, as follows:
Component A – a base component composed of epoxy resin and solvents.
Component B – a curing agent containing polyamide or amine resin and solvents.
Component C (optional) – thinning component composed predominately of organic solvents.
Component B shall act as the curing agent for component A.
The components shall be packaged separately and furnished as a kit. Pigments may be included with either component A or B. When the components are mixed in the proportions specified by the manufacturer, a primer coating meeting the requirements of this specification shall result. Chlorinated solvents, except for para-chlorotrifluoromethylbenzene or equal, shall be prohibited in the formulation of these primer coatings. Incidental cadmium and cadmium compounds shall be not greater than one part per million (ppm). The non-volatile portion shall contain not more than 0.05 percent by weight of lead metal or lead compounds.
The primer coatings are of the following types and classes, as specified:
Types: The types of primer coatings are as follows:
Type I – Standard pigments
Type II – Low infrared reflective pigments
Classes: The classes of primer coatings are as follows:
Class C1 – Barium chromate based corrosion inhibitors
Class C2 – Strontium chromate based corrosion inhibitors
Class N – Non-chromate based corrosion inhibitors
Class C1. Primer coatings containing barium chromate based corrosion inhibitors, along with extenders and other pigments, shall be identified as class C1.
Class C2. Primer coatings containing strontium chromate conforming to ASTM D1649 as the corrosion inhibitor, along with extenders and other pigments, shall be identified as class C2.
Class N. Primer coatings containing non-chromium corrosion inhibitors, along with extenders and other pigments, shall be identified as class N. Incidental hexavalent chromium content of class N primer coatings shall be not greater than 5 ppm.
Volatile organic compound (VOC) content: The VOC content of admixed primer coatings shall be not greater than 340 g/L (2.8 lb/gal). The resistivity of the solvents shall permit application of the coatings by electrostatic spray application.
Thinner compatibility: The admixed primer coatings shall be compatible with thinner conforming to MIL-T-81772, type II.
Sherwin-Williams Aerospace Coatings MIL-PRF-23377 (QPL-23377) Type 1, Class C2
» MIL-PRF-23377K Type 1, Class C2, Yellow
» Primer (Part A): E90G203
» Catalyst (Part B): V93V230
» MIL-PRF-23377K Type 1, Class C2, Green
» Primer (Part A): CM0724933
» Catalyst (Part B): CM0120933
» MIL-PRF-23377F Type 1, Class C2, Yellow
» Primer (Part A): CM0724400
» Catalyst (Part B): CM0724114
Also Known As:
» Chromated Primer
Follow all manufacturer instructions and technical directives.
The following instructions are relevant to Sherwin-Williams MIL-PRF-23377 Type 1 Class C2 Chromated Epoxy Polyamide Primer, Part Number CM0724933.
To insure proper primer adhesion to the substrate, all contaminates must be removed. Depending on the type of substrate to be prepared, different methods should be used. There are a variety of processes to prepare these substrates for primer and painting. Sherwin-Williams primers are designed to go over various treatments (i.e., alclad or anodized aluminum, composite, fiberglass, magnesium, and stainless steel). Please refer to recommendations for cleaning, application, and preparation before painting to the manufacturer of the treatment.
Shake primer component for 15 minutes before admixing.
Admix by Volume:
3 Parts Epoxy Primer Component CM0724933
1 Part Epoxy Adduct CM0120933
Add the required volume (up to a maximum of 1½ part) of CM0110933. This additional reduction may change the application VOC to greater than 2.9 lbs./gal. (350 g/L) depending on the legislation in your area. Admixed product should be allowed a 30-minute induction time for optimum application performance. It is recommended to filter strain admixed primer before placing material in containers for spraying.
This product can be applied using conventional air spray, HVLP, Graco electrostatic airspray, or air assisted airless. Please consult your Sherwin-Williams representative for specific equipment settings.
Electrostatic users: Ensure that the aircraft is properly grounded for potential static buildup. Best spray application results are obtained by applying one light continuous closed film cross coat.
Recommended dry film thickness is 0.6 – 0.9 mils (15-23 microns).
NOTE: Application of these product systems requires recommended temperature / humidity conditions and film thickness ranges. The material, hangar, and aircraft skin temperature should be no lower than 55ºF / 13ºC before, during, and after application.
Dry times are based on the dry film thickness of 0.6-0.9 mils (15-23 microns).
Air Dry Times (75°F / 25°C and 50% RH)
To apply topcoat: Min. 2 hours; Max 72 hours*
Tack free: Min. 5 hours
Dry Hard: Min. 8 hours
Force Dry: (140ºF (60ºC), 45% RH
Dry Hard: Min. 45-60 minutes
* If an intermediate primer or topcoat is not applied within 72 hours of primer application, light scuff sanding using P240,P320 paper &/or red abrasive pad will be required for good intercoat adhesion.
NOTE: Lower temperatures, heavy film thickness, improper activator range selection and poor air movement will extend the dry time.
Use clean Ketone–type solvents such as CM0110308 MEK. Do not allow material to cure inside equipment.
Type I. The color of the admixed type I primer coatings shall be the natural color of the corrosion inhibiting pigments used. Tinting to a different shade is permitted.
Type II. The color of the admixed type II primer coatings shall be dark green, black, or gray.