Without knowing further details, the procedure is as follows : Use of a less reactive melamine resin. The course of reaction can also be influenced by siccatives of which there is a large choice. The amount and type of anti-skinning agents, which are indispensible in oxidative drying enamels must be carefully selected. Unless there are particular reasons for using a melamine resin as a second binder, the use of a copolymer or a chlorinated polyolefin (chlorinated rubber) is preferred.
The choice is very large and depends on the characteristics demanded of the lacquer and its area of application.
There is no basically effective method of regenerating a thickened enamel. The addition of a certain quantity of butanol can be effective. Surfactants which lower viscosity can impair the quality of the lacquer. The simplest method is to mix in small amounts to give an extra low viscosity product. In any case, it depends on the degree of thickening. Storage in cool surroundings goes without saying.