JPS6431994A - Electrodeposition coating method - Google Patents

Abstract

PURPOSE:To easily coat an automobile body, etc., with only two stages of electrodeposition coating by applying a first electrodeposition coating having the same color as a final coating, and applying a second electrodeposition coating on the inside of the first electrodeposition paint film with a backing electrodeposition paint while the first paint film is still wet at the time of coating the automobile body. CONSTITUTION:The body 1 of an automobile is cleaned, degreased, and chemical-conversion treated in a surface-treating stage 2 to form a zinc phosphate film 10. The film is then washed with water in a water washing stage 2A, and dried in a drying stage 3. The body is then dipped in the water-based paint 5B in a first electrodeposition coating vessel 5A in a first electrodeposition coating stage 5 of a electrodeposition coating process 4. In this case, the body is dipped in the paints of the same kind and number as the top coats in black, white, red, gray, etc. A voltage at 250-300V is impressed on the electrode 5C in the coating vessel 5A to form a first electrodeposition paint film 11. The body is immediately dipped in a paint soln. 6B contg. a second gray electrodeposition paint in a second electrodeposition coating stage 6, a voltage at 250-300V is impressed by an electrode 6C, a backing paint film 12 by the second electrodeposition paint 6B is formed by electrophoresis under the still-wet first electrodeposition paint film 11, and the body is easily coated by electrodeposition with those two stages.