[hpsdr] Munin heat sink and spreader

[rodwall1234 at gmail.com]

Hi Mike,


Are you sure that the edge of the copper spreader is straight?


Roderick Wall, vk3yc.



From: AA8K73 GMail
Sent: ‎Thursday‎, ‎October‎ ‎10‎, ‎2013 ‎1‎:‎36‎ ‎PM
To: HPSDR

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Has anyone else noticed a concave surface in the heat sink in 
the latest Munin kit?

When I hold the copper spreader against the heat sink, it 
touches on the ends, but the middle portion is about 1 mm away. 
  I could:


1. File the copper spreader and/or aluminum heat sink to get a 
closer fit.

2. Put the copper spreader in my arbor press and bend it to 
conform to the heat sink.  But then it wouldn't be flat for the 
transistors.

3. Fill the gap with something to provide a better heat transfer 
than air.

4. Not worry and just screw it together.


What do you think?


Also, what about using Penetrox (zinc particles in petroleum) in 
place of ordinary heat sink compound (ceramic particles in 
silicon, I think) for the spreader/sink interface?  I've used 
Penetrox frequently in industrial electrical work when joining 
aluminum with copper.


Mike - AA8K
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