FED-STD-228A
Method 7111.1
18 APRIL 2014
ZINC COATING, STEEL ARMOR
1. SCOPE
1.1 This method is intended for use in determining the uniformity of zinc coating on steel armor of
insulated cable.
2. SPECIMEN
2.1 The specimen should be the armor removed from a piece of the inspection unit at least 6 inches in
length.
3. APPARATUS AND REAGENTS
3.1 The apparatus and reagents shall be as follows:
3.1.1 Glass container with 2-inch inside diameter for testing No. 12-gage wire and smaller, and 3-inch
inside diameter for wires larger than 12 gage.
3.1.2 Copper-sulfate solution, specific gravity 1.186.
4. PROCEDURE
4.1 Preparation of standard copper-sulphate solution. The solution shall be prepared by dissolving
commercial copper-sulphate crystals in distilled water. Enough crystals should be added to insure a
solution which, when cooled to 18°C, will have a specific gravity of at least 1.186. One gram of cupric
oxide (CU2O) per liter shall be added to the solution for the purpose of neutralizing any free acid which
may be present. The solution shall be diluted with water to a specific gravity of 1.186 at 18°C (65°F).
The solution shall be renewed for each specimen tested.
4.2 The specimen shall be free from mechanical damage. The surface of one end of the specimen shall
be cleaned for a length of at least 3 inches by means of the solvent, rinsing with water, and drying with
cheesecloth. The cleaned portion of the specimen shall not be allowed to contact the hands or foreign
matter previous to immersion in the copper sulfate solution. Standard copper sulfate solution shall be
added to the container to a depth of 2.5 inches and the temperature adjusted to 18°C (65°F). The
cleaned 3-inch length of the specimen shall be immersed in the solution by placing it in the center of the
container in a vertical position. The specimen shall remain in the solution for 60 seconds without being
moved or the solution stirred. At the end of the immersion period, it shall be removed from the solution,
rinsed with running water while being rubbed lightly with cheesecloth to remove any loosely adhering
black deposit, and dried with cheesecloth. The surface of the specimen shall be examined for bright
copper deposit, avoiding contact of the surface with the hands during the cleaning, drying, and examining
period.
4.3 Unless otherwise specified in the detail specification, one additional immersion and examination shall
be made as described in 4.2.
4.4 The percentage of the total area of the specimen showing fixed copper deposit shall be determined
by visual examination.
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