Zinc chromate primer is intended for use as a general-purpose interior protective coating for metal surfaces. Depending on the location, zinc chromate primer may or may not require a topcoat. Primer is relatively easy to apply and remove. Zinc chromate primer is a single component. You should thin primer with TT-T-548 toluene or TT-M-261 methyl ethyl ketone. Do not use zinc chromate primer on exterior aircraft surfaces, wheel wells, wing butts, or in areas that are exposed to temperatures exceeding 175F (79.4C).

Most enamel finishes used on aircraft surfaces are baked finishes that cannot be touched up by organizational or intermediate levels of maintenance. Minor damage to conventional enamel finishes ordinarily used on engine housings is repaired with epoxy topcoat material or air-drying enamel.

Elastomeric coatings are used as a coating system to protect the exterior laminated plastic parts of high-speed aircraft, missiles, and helicopter rotor blades from rain erosion. They offer good resistance to the effects of weather and aromatic fuels. Excellent adhesion is obtained after a 7-day drying period.

Repairs to these coatings in the field are impracticable because of the long curing time. Kits are available to repair coatings where limited touchup is required. These kits contain a primer, neoprene topcoat, and antistatic coating. If the radome or leading edge coatings are in bad condition, they should be stripped completely and recoated with epoxy primer and acrylic topcoat as a temporary measure. If schedules and conditions permit adequate curing of elastomeric coatings, these original coatings may be replaced.

The repair kits are normally bought open purchase to ensure that fresh materials are available. They should be stored in a cool place or refrigerated. Heat accelerates their aging. Stripping fiber glass surfaces should be done according to the current maintenance instructions. Elastomeric coatings are toxic and flammable and must be used with care.

General safety precautions for all painting as well as those for special types of paints must be observed. These precautions include the following:

No eating, drinking, or smoking is allowed in areas where paint or solvent is being used. 

Prolonged breathing of vapors from organic solvent or materials containing organic solvent is dangerous. Prolonged skin contact with organic solvents or materials containing organic solvents can have a toxic effect on affected skin areas.