[Beowulf] materials for air shroud?

[Robert G. Brown]

On Wed, 31 Aug 2011, David Mathog wrote:

> Robert G. Brown wrote
>
>> Also thin aluminum.
>
> No way, at least not anywhere near the motherboard.  There isn't going
> to be a way to fasten it very tightly into position, just tape probably,
> possibly a zip tie at the back end.  So it would be best if the shroud
> cannot short things out or scratch components off the motherboard if it
> falls out of position.

Don't forget the virtue of coat hangers.  Even rubber coated ones.

If you made the shroud out of aluminum, you could basically paint the
bottom with liquid electrical tape (or better, dip it four or five
times, drying it in between).  It would basically rubber-coat it.  No
shorting, no scratching, still moderately fireproof.  But as you wish.

> I'm thinking perhaps 1/16" polypropylene, that may be stiff enough for
> this, and it is similar to the shroud material we have in another server.

The biggest problem with stuff like this (IIRC a discussion from long
ago) is you have to worry about what and how toxic it is in a fire, at
least if you want fire-persons to be able to enter the room in a fire.
Many plastics burn into really toxic materials.  You also have to worry
about how it will cope with high heat.  The good thing about aluminum is
that by the time it melts you won't care.  I think some of the liquid
tape compounds are fire retardant/melt resistant, and the aluminum
itself is such a good conductor of heat that it will act as a heat sink
for the rubber coating (in a good way).

    rgb

>
> Regards,
>
> David Mathog
> mathog at caltech.edu
> Manager, Sequence Analysis Facility, Biology Division, Caltech
>

Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu