Bob,
  I apologize in advance for the story I'm about to tell, so be forewarned.
I liked your comment regarding, punching a bunch of holes in a PC board was
useless. In fact, I believe you're correct to the tee. I would like to share
a comment I heard a looong time ago regarding vehicle brakes. One of the
guys that worked for my father said, "Why would you turn the drums or smooth
the surface of those brake drums and disks? With all those deep scores and
valleys, look at all the extra surface area you have for friction"... With
that being said, sometimes it's all from a point of view...  BTW, he was
kidding.
Later...

Regards,
Scott Decker

                     AKA: PadMasterson
   /\     Sr. PCB Designer, Portland
  /\/\    7245 NW Evergreen Pkwy., Suite 100, Hillsboro OR 97124
 /\/\/\   (503)531-2050 ext. 1820 FAX: (503)531-2051
/\/\/\/\ [log in to unmask] <mailto:[log in to unmask]>
 Praegitzer Industries, Inc.
The Fine Line in Printed Circuits




        -----Original Message-----
        From:   Bob Landman [SMTP:[log in to unmask]]
        Sent:   Tuesday, November 16, 1999 5:54 PM
        To:     [log in to unmask]
        Subject:        Re: [DC] Calculating thermal dissipation of external
plane heat sink area


        I still maintain that punching a bunch of holes in a PC board with
        clad on both sides to serve as a heat sink is a worthless endeavor
but
        do what you will.  Until and unless I see some math to back it up, I
        for one, will not use the technique.  I've done more than my share
of
        optical and temperature measurements (critical fluctuations of CO2
at
        its triple point [where it is a gas/liquid and solid] is one such
        experiment and it took THREE boxes within boxes with three
temperature
        control loops to do it {to hold the temp to a millidegree} but
before
        we did the experiments, we had an idea where we were headed and used
        math to get there.

        That is THE way to be "precise", in my opinion.

        Bob Landman
        H&L