Heat Transfer Compound, often referred to as heat transfer mastic, is a compound used to enhance the thermal performance of bolt-on heating products. The compound is applied to the bolt-on jacket at time of installation. Heat transfer compound consists of graphite and one or more binder components which are formulated for different applications. Graphite is a good heat conductor with half the thermal conductivity of aluminum and more than 100 times the conductivity of air.
For ControTrace® heating elements and panels, CSI recommends its Grade-B ControTrace® Thermal Compound. Grade-B is a non-hardening compound composed of a high-temperature petroleum derivative and graphite. Its maximum service temperature is 400°F. At room temperatures, Grade-B has the consistency of heavy grease. Its workability decreases with decreasing ambient temperature, becoming very stiff near freezing temperatures. Grade-B is not soluble in water. It will dissolve in light mineral oils. It has an unlimited shelf life and is provided in one-gallon containers.
For ControHeat® jackets, CSI recommends its Grade-1 ControHeat® Thermal Compound. Grade-1 is a hardening, water soluble compound composed of silica compounds and graphite. The silica binder causes the compound to become rigid as it dries. Its maximum service temperature is 750°F. The consistency of Grade-1 from freshly opened containers is like a thick paste. It is workable at temperatures above freezing and should be stored above 32°F. Grade-1 has a 1-2 year shelf life and is provided in one-gallon containers. Special grades of the material are available for higher temperature service.
Material Safety Data Sheets are available for CSI’s heat transfer compound: