Instructions for painting the M4 Sherman tank from the Technical Manual TM 9-731B: Medium Tank M4A2, January 1943.
Section XXV: PAINTING
145. PAINTING.
a. Ordnance materiel is painted before issue to the using arms. One maintenance coat per year will ordinarily be ample for protection. With but few exceptions, this materiel will be painted with ENAMEL, synthetic, olive drab, lusterless. The enamel may be applied over old coats of long oil enamel and oil paint previously issued by the Ordnance Department if the old coat is in satisfactory condition for repainting.
b. Paints and enamels, usually issued ready for use, are applied by brush or spray. They may be brushed on satisfactorily when used unthinned in the original package consistency or when thinned no more than 5 per cent by volume with THINNER. The enamel will spray satisfactorily when thinned with 15 per cent by volume of THINNER. (Linseed oil must not be used as a thinner in this enamel, since it will impart an undesirable luster.) If sprayed, enamel dries rapidly enough to permit repainting after one-half hour, and dries hard in 16 hours.
c. Certain exceptions to the regulations concerning painting exist. Fire-control instruments, sighting equipment, and other associated items will not be painted.
d. Complete information on painting is contained in TM 9-850.
146. PREPARING FOR PAINTING.
a. If the base coat on the materiel is in poor condition, it is more desirable to strip the old paint from the surface than to use sanding and touchup methods. After stripping, it will be necessary to apply a primer coat.
b. PRIMER, ground, synthetic, should be used on wood as a base coat for synthetic enamel. It may be applied by either brushing or spraying. Primer will brush satisfactorily as received or after the addition of not more than 5 per cent by volume of THINNER. It will be dry enough to touch in 30 minutes, and hard in 5 to 7 hours. For spraying, primer may be thinned with not more than 15 per cent by volume of THINNER. Lacquers must not be applied to PRIMER, ground, synthetic, within 48 hours.
c. PRIMER, synthetic, rust inhibiting, for bare metal, should be used on metal as a base coat. Its use and application are similar to those outlined in the preceding paragraph.
d. The success of a job of painting depends partly on the selection of a suitable paint, and largely on the care used in preparing the surface. All parts to be painted should be free from rust, dirt, grease, kerosene, oil, and alkali, and must be dry.
147. PAINTING METAL.
If metal parts to be painted are in need of cleaning, they should be washed in a solution of SODA ASH in warm water, in the ratio of one-half pound to 8 quarts, then rinsed in clear water and wiped thoroughly dry. Wood parts in need of cleaning should be treated in the same manner, but the alkaline solution must not be left on for more than a few minutes, and the surfaces should be wiped dry as soon as they are washed clean. When artillery or automotive equipment is in fair condition and marred only in spots, the bad places should be touched up with ENAMEL, synthetic, olive drab, lusterless, and permitted to dry. The whole surface will then be sandpapered with PAPER, flint, No. 1, and a finish coat of ENAMEL, synthetic, olive drab, lusterless, applied and allowed to dry thoroughly before the materiel is used. If the equipment is in bad condition, all parts should be thoroughly sanded with PAPER, flint, No. 2, or equivalent, given a coat of PRIMER, ground, synthetic, and permitted to dry for at least 16 hours. They will then be sandpapered with PAPER, flint, No. 00, and wiped free from dust and dirt. A final coat of ENAMEL, synthetic, olive drab, lusterless, will be applied and allowed to dry thoroughly before the materiel is used.
148. PAINT AS A CAMOUFLAGE.
a. Camouflage is now a major consideration in painting ordnance vehicles, with rust prevention secondary. The camouflage plan at present employed utilizes three factors–color, gloss, and stenciling.
(1) Color. Vehicles are painted with ENAMEL, synthetic, olive drab, lusterless, which blends in reasonably well with the average landscape.
(2) Gloss. Lusterless enamel makes a vehicle difficult to see front the air or from relatively great distances over land. A vehicle painted with ordinary glossy paint can be detected more easily and at greater distances.
(3) Stenciling. A blue-drab stencil enamel, which cannot be photo graphed from the air, is used. Blue-drab markings are illegible at distances exceeding 75 feet.
b. Preserving camouflage.
(1) Continued friction or rubbing must be avoided, as it will smooth the surface and produce a gloss. The vehicle should not be washed more than once a week. Care should be taken to see that the washing is done entirely with a sponge or a soft rag. The surface should never be rubbed or wiped except while wet, or a gloss will develop.
(2) It is not desirable that vehicles painted with lusterless enamel be kept as clean as vehicles were kept when glossy paint was used. A small accumulation of dust increases the camouflage value. Grease spots should be removed with SOLVENT, dry cleaning. Whatever portion of the spot cannot be so removed should be allowed to remain.
(3) Continued friction of wax-treated tarpaulins on the sides of a vehicle will produce a gloss, which should be removed with SOLVENT, dry cleaning.
(4) Tests indicate that repainting with olive drab paint will be necessary once yearly, with blue-drab paint twice yearly.
149. REMOVING PAINT.
After repeated paintings, the paint may become so thick as to crack and scale off in places. Before repainting, remove the old paint by use of a lime-and-lye solution (see TM 9-850 for details) or REMOVER, paint and varnish. It is important that every trace of lye or other paint remover be completely rinsed off and that the equipment be perfectly dry before repainting is attempted. It is preferable that the use of lye solutions be limited to iron or steel parts. If used on wood, the lye solution must not be allowed to remain on the surface for more than a minute before it is thoroughly rinsed off and the surface wiped dry with rags. Crevices or cracks in wood should be filled with putty, and the wood sandpapered, before refinishing.
150. PAINTING LUBRICATING DEVICES.
Oil cups, grease fittings, and similar lubricating devices, and a circle about three-fourths inch in diameter at each oil hole and at each device, will be painted with ENAMEL, red, water resisting, in order that they may be readily seen.
