Film Thickness Requirements

Custom Search

Coating for Bilges and Tanks (Except Potable Water Tanks)

TB-43-0144 Painting of Watercraft Manual

Switchboards and Panels.

d. Film Thickness Requirements:

(1) WFT to DFT thickness ratios should be locally determined for the selected coating. Use the same

mixing and application procedures used for ship tank painting. Painters should be instructed to apply

paint within a WFT range that will result in the required DFT. All potable water tank painters should be

supplied with WFT gages.

(2) Procedures shall be instituted to ensure that for at least 98% of the tank surface area, the total

thickness of the applied paint system is no greater than the total number of coats applied multiplied by the

maximum allowable per-cost thickness.

(3) Adequate painting for preservation may result in excessive thickness near angular shapes. In

isolated areas, near stiffeners for example, the maximum DFT may be exceeded by up to 2 mils per coat,

provided that the total non-complying area is less than 2 percent of the total tank surface. For touchup or

over coating intact aged paint in good condition, the same requirements apply. The total film thickness

requirement may be corrected to allow for the thickness of underlying paint. The requirement is to avoid

excess thickness in individual coats. High DFT resulting from properly applied extra coats is not

considered a problem below 35 mils total.

e. Quality Assurance. Minimum quality assurance inspections for potable water tank coatings shall

include:

(1) Surface preparation (to ensure freedom from surface dirt, moisture, or other contaminants).

(2) DFT of any remaining aged coating.

(3) DFT after application of each coat, recording at least five measurements per 1,000 square feet of

surface.

(4) Hardness of paint (to ensure that each coat has cured thoroughly).

7-6. Electric and Electronic Equipment.

a. Electric and electronic equipment will usually be supplied, painted, and preserved as required by

either the individual purchase specifications or the operating manual. Painting and preservation may be

necessary if the equipment is received in an unpainted condition or if the coating has been damaged

during shipment. In addition, painting and preservation are necessary for finishing and installation.

b. Except as otherwise specified, the painting and preservation of electric and electronic equipment shall

comprise: One coat of epoxy primer applied to bare metal surfaces only

7-7. Motors and Generators. Motors and generators shall be painted in accordance with specifications

given in the following.

a. Exterior Parts. Except for shafts and identification plates, paint exterior parts in accordance with

b. Interior Parts. Electrical insulation of all types, surfaces in contact with lubricating oil or grease,

commutators, collector rings, brushes, bearings, and bearing surfaces shall not be painted. Do not paint

peripheries of armatures and rotors or any other rotating part of a machine from which centrifugal force

may cause the paint to be thrown on to the windings when the machine is operated at rated load and

rated ambient temperature. Insulation varnish, instead of paint, may be applied to such parts. Paint other

corrosion-resistant parts in accordance with paragraph 7-6.b. above.

c. Apply one coat of epoxy primer followed by one coat of white enamel to the inside of both ends of the

enclosure of water or air-cooled motors and generators.