View Full Version : Heat sink compound = dielectric grease?
11-16-2009, 05:07 PM
Are they one in the same?
11-16-2009, 06:03 PM
No, the true heat sink compound is a blend of beryllium oxide and siloxane. and has a much higher thermal conductivity than dielectric grease (siloxane).
11-16-2009, 07:26 PM
Off to "The Shack".
11-25-2009, 11:08 PM
Dielectric refers to something that is essentially an electrical insulator (di = anti). The term is often used to describe the insulators used between the plates of capacitors where a high dielecrtric constant (air = 1) can increase the capacitance of the capacitor for a given weight and volume. But it is also used for many other kinds of elecrtical insulators. Hence, dielectric grease is a grease that is also an electrical insulator. It can be used for a variety of reasons in an electric or electronic device: lubrication, moisture resistance, corrosion resistance, etc.
A heat sync compound is a mixture of substances that have a high THERMAL conductivity. It may or may not be an electric insulator. It is used to fill the gaps between a heat producing device that needs to be cooled and some kind of heat sync to allow the heat to flow into the heat sync more readily.
A dielectric grease may be and often is one of the components of this mixture as it us frequently desirable to have electric insulation between the electronic device and the heat sync to prevent shorts. Many times the heat sync compound is combined with a thin mica or other type of insulator for this purpose.
11-26-2009, 02:09 PM
And the secret to using heat sink compound is to use as little as possible. It's only supposed to fill the gaps between the metal surfaces. The compound will never provide better heat transfer than a 100% metal to metal contact. Gamers who seriously over overdrive thier CPUs even lapp the mating surfaces,
A trick used with good results: Add small amount of compound to heat sink. Use a single edge razor blade to spread it evenly, then use that same blade to scrape it clean. There will be a very thin film and all imperfections will be filled. Repeat on the other surface.