<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I used sandpaper and a lot of elbow grease on both the heat sink and copper spreader....<div><br></div><div>Phil</div><div>N6AS<br><div><br><div>Begin forwarded message:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>From: </b></span><span style="font-family:'Helvetica'; font-size:medium;">Mike Culver <<a href="mailto:mculver@extencia.com">mculver@extencia.com</a>><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>Subject: </b></span><span style="font-family:'Helvetica'; font-size:medium;"><b>Re: [hpsdr] Munin heat sink and spreader</b><br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>Date: </b></span><span style="font-family:'Helvetica'; font-size:medium;">October 9, 2013 7:42:45 PM PDT<br></span></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px;"><span style="font-family:'Helvetica'; font-size:medium; color:rgba(0, 0, 0, 1.0);"><b>To: </b></span><span style="font-family:'Helvetica'; font-size:medium;">HPSDR <<a href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</a>><br></span></div><br><div>***** High Performance Software Defined Radio Discussion List *****<br><br>Not 100%, but isn't Penetrox for aluminum wire joints? It's a great anti-oxidant but not a great heat transfer agent.<br><br>I'd vote for filing in order to address the concave issue.<br><br>Mike<br>WA9QHP<br><br>-----Original Message-----<br>From: <a href="mailto:hpsdr-bounces@lists.openhpsdr.org">hpsdr-bounces@lists.openhpsdr.org</a> [mailto:hpsdr-<a href="mailto:bounces@lists.openhpsdr.org">bounces@lists.openhpsdr.org</a>] On Behalf Of AA8K73 GMail<br>Sent: Wednesday, October 9, 2013 7:36 PM<br>To: HPSDR<br>Subject: [hpsdr] Munin heat sink and spreader<br><br>***** High Performance Software Defined Radio Discussion List *****<br><br><br>Has anyone else noticed a concave surface in the heat sink in the latest Munin kit?<br><br>When I hold the copper spreader against the heat sink, it touches on the ends, but the middle portion is about 1 mm away. <br> I could:<br><br><br>1. File the copper spreader and/or aluminum heat sink to get a <br>closer fit.<br><br>2. Put the copper spreader in my arbor press and bend it to <br>conform to the heat sink. But then it wouldn't be flat for the <br>transistors.<br><br>3. Fill the gap with something to provide a better heat transfer <br>than air.<br><br>4. Not worry and just screw it together.<br><br><br>What do you think?<br><br><br>Also, what about using Penetrox (zinc particles in petroleum) in <br>place of ordinary heat sink compound (ceramic particles in <br>silicon, I think) for the spreader/sink interface? I've used <br>Penetrox frequently in industrial electrical work when joining <br>aluminum with copper.<br><br><br>Mike - AA8K<br>_______________________________________________<br>HPSDR Discussion List<br>To post msg: <a href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</a><br>Subscription help: <a href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org">http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</a><br>HPSDR web page: <a href="http://openhpsdr.org">http://openhpsdr.org</a><br>Archives: <a href="http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/">http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/</a><br>_______________________________________________<br>HPSDR Discussion List<br>To post msg: <a href="mailto:hpsdr@openhpsdr.org">hpsdr@openhpsdr.org</a><br>Subscription help: <a href="http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org">http://lists.openhpsdr.org/listinfo.cgi/hpsdr-openhpsdr.org</a><br>HPSDR web page: <a href="http://openhpsdr.org">http://openhpsdr.org</a><br>Archives: <a href="http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/">http://lists.openhpsdr.org/pipermail/hpsdr-openhpsdr.org/</a><br></div></blockquote></div><br></div></body></html>