Coatings update: electrocoating

Electrocoating paints enjoyed a sales volume of $26 million in 1974 and it was predicted that this would double by 1978 Chemical & Engineering News [52, August 26 (1974) p. 10]. The article describes some of the advantages of electrocoating including the fact that paint particles penetrate cracks and flaws in the metal because of electrical attraction. With dipping or spraying, on the other hand, the paint tends to bridge these areas rather than to duplicate the precise profile of the subtrate. Another advantage of the electrocoating process is its ability to achieve a coating of uniform thickness for this is controlled by the extent of the charge of the object being coated. Efficiency of the process is demonstrated by the fact that more than 95% of both the resin and the pigment are utilized as compared with 80% for other dip procedures and as little as 50% for spray coating methods. Two of the disadvantages described include the fact that it can be used only on electrical conductors such as metal and that it shares in common with other dip procedures considerable difficulty and expense when it comes to colour changes.