High Temperature Paint / Coatings

High Temperature coatings are specialized materials. These coatings are designed for temperatures of 300-1400F. Selection depends upon the temperature profile and type of substrate that is to be painted. Understanding how they work and how to specify and apply them will help to ensure proper service and eliminate such problems as disbondment, discoloration and early failure.

BASICS: For high temperature applications, the coating system is expected to retain its appearance and integrity while protecting metal substrates at temperatures above (300F) (150C). The coating may be subjected to corrosion. In general, coatings are made up of a resin or vehicle, pigments and solvents. Conventional coatings, such as alkyds, use organic vehicles as pigments binders. However, these vehicles may decompose under heat, and this can cause premature failure.

To overcome this problem, high temperature coatings use heat resistant resins. These resins compounds have excellent thermal stability and resistance to oxidation. They are also essentially transparent to, and resistant to degradation by ultraviolet radiation.

The combination of heat resistant properties and weathering characteristics make these resins and outdoor powder coating ideal for formulation into heat resistant maintenance coatings. Other coatings can be formulated with substitute resins which will reduce cost per gallon while improving properties such as adhesion, abrasion resistance and curing time.

The pigments used must be compatible with the resin and should not decompose at high temperatures. Pigments must also be color stable over the entire working temperature range of the coating. Thermally stable pigments keep their color over time, unlike other pigments on the market and so are used in high temperature coatings. Traditionally, only black and aluminum colored heat stable pigments were available. Now, there is a wide range of colors, including pigments that will support numerous color matching options.