[hpsdr] Munin heat sink and spreader

[Tim ORourke]

Yes we hand scrape mating surfaces where necessary.
We call transfer midia Blueing, you can actually obtain from good old time auto supply store, also used to verify valve seating face contact.
The spreader MAY be overkill for 100 watts, I built Hercules, and 2 Munin amps without spreader. I machined heatsink to accmodate finals and linear devices and have not had any overheating issues at all. The extra heat transfer surface created by adding spreader takes away some of the higher heat transfer of copper. Copper is a good thing but from practicle experience I do not fine the necessity for 100 watts with adequate heat sink. I do not use digital modes very often so your eperience may be different however I believe with a small fan (mine has never come on using Hercules or Munin) the spreader MAY not be necessary.
I am no thermal engineer though just my 3.5 cents worth.
Tim W4YN


-----Original Message-----
>From: Michael Young <mikewhy at sbcglobal.net>
>Sent: Oct 10, 2013 8:56 AM
>To: aa8k73 at gmail.com
>Cc: HPSDR <hpsdr at openhpsdr.org>
>Subject: Re: [hpsdr] Munin heat sink and spreader
>
>***** High Performance Software Defined Radio Discussion List *****
>
>I would make a cup of tea, put out some transfer dye, and just have at it with the file. I thought you old tool and die guys did this sort of thing by hand scraping. If I really wanted a project, I suppose it wouldn't take much coaxing on flattened water stones to put a mirror finish on the soft aluminum, possibly with a second cup of tea.
>
>AA8K73 GMail <aa8k73 at gmail.com> wrote:
>
>>***** High Performance Software Defined Radio Discussion List *****
>>
>>
>>The copper spreader is fine, the aluminum sink is curved.  The 
>>spreader is only 3 cm wide, so it's a narrow trough.  Still a 
>>lot of metal to remove.  And the challenge of making it flat. 
>>Maybe I'm talking myself into milling it.
>>
>>My father was a tool maker.  You guys are artists.
>>
>>
>>On 10/10/2013 06:26 AM, Tim ORourke wrote:
>>> You would have to spend a lot of energy with a file to remove 1mm from copper with a file!
>>> Old tool maker here Tim W4YN
>>>
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Tim O'Rourke 
W4YN at ARRL.Net
Low Power Amateur Radio Rocks 
Member of Flying Pigs,ARCI,GQRP,RSGB,ARRL Life Member
NHRA Life Member

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