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Re: [Amps] SSPA & Heatsink Compounds

To: Amps <>
Subject: Re: [Amps] SSPA & Heatsink Compounds
From: Bill Turner <>
Date: Thu, 12 Dec 2013 12:27:18 -0800
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On Thu, 12 Dec 2013 14:43:10 +0000, Manfred wrote:

>For that reason I use a radically different technique: I apply a single 
>thick round blob of thermal compound to the middle of the mounting 
>surface, or if the device is long, I apply a single nice smooth string 
>of compound to it. Then I mount it, pressing it down strongly but 
>evenly, to make the compound flow out and fill the whole space. In this 
>way the formation of air pockets is avoided. When thermal compound 
>appears squeezed out all around the device, I can be sure that no air 
>remains anywhere under the part. From this point on, additional pressure 
>can be used to thin out the layer of thermal compound. This pressure 
>should be well distributed over the device, to avoid deforming it. Just 
>tightening the mounting screws is not a good idea. A clamp in the middle 
>of the device is ideal.
>If necessary, the device and heatsink can be warmed up to soften the 
>thermal compound and make it flow out more easily. Otherwise it's a good 
>idea to re-tighten the mounting screws during the first test run, when 
>the equipment and specially the power devices get warm.
>Since I'm a hopeless cheapskate, I scoop up the excess thermal compound 
>that squeezes out, and use it for the next device.
>This method has worked well for me, in 35 years building electronic 
>equipment, and is easy and quick.


Excellent idea. Will definitely use it. Thanks!!

73, Bill W6WRT
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