Prep and primer
The model should first be thoroughly washed with a good liquid detergent such as Dawn dishwashing detergent and warm water. All automotive primers are not the same. Most contain talcum power as a filler. I have had excellent results with Dupli-Color grey Primer Sealer. A twelve ounce spray can sells for five dollars at auto parts stores. A light mist coat is followed by two heavier coats, ten minutes apart. This results in a perfectly smooth finish and is thin enough not to obscure fine details. It is important to spray in an evironment of about seventy degrees Fahrenheit to ensure the proper viscosity.