From: Watson 'Atto Parsec' Name
Subject: Re: luxeon star leds
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Date: Wed, 27 Nov 2002 23:36:09 -0800
NNTP-Posting-Date: Thu, 28 Nov 2002 00:34:22 PST
Organization: InReach Internet
In article ,
firstname.lastname@example.org talked about...
> I read in sci.electronics.design that Watson 'Atto Parsec' Name
> wrote (in ach.net>) about 'luxeon star leds', on Wed, 27 Nov 2002:
> >I have mounted my Star/O LEDs on small pieces of metal brackets inside of
> >project boxes. They do not have a problem with overheating even tho
> >they're totally enclosed. You have to remember that the plastic itself
> >conducts heat, as does a PC board.
> Yes, but very poorly.
Well, I would say better than air.
> > I have run them at full power for
> >perhaps a half hour or more and they don't seem to get hot. On the first
> >one I built, I used a piece of 1" wide by 4" long copper, bent into an 'L'
> >shape of 1 by 3 inches. It is mounted inside of the box, with the LED
> >mounted to the 1" upright part. It barely gets warm. So with later ones I
> >made I used a much smaller bracket of aluminum. Works just fine.
> The *thickness* matters as well as the area. If you use very thin
> material, the area round the device gets hot, but the more distant parts
> stay cool. What thickness did you use?
Maybe .050? It's thinner than PC board. It still conducts heat *very*
well, about twice as well as aluminum. So it needs to be only about half
> For aluminium, the grade matters as well. The softer the better for the
> heat conduction, but very soft stuff is hard to work.
Yeah, if you use a butter knife to cut it. I've used aluminum from old car
tape players that was so soft that it was bendable by hand, w/o a vise.
But most of the stuff I've used for HS has been T6 tempered stuff. I
mounted one Luxeon on a piece of aluminum sawed from the front panel of an
old WW2 or Korean war military gear, maybe naval(?). The reason I guess
that is that no one would make something that thick and heavy, for use in a
land-based vehicle, and it's painted battleship grey. But it's a full
.125" (3 mm) thick! I said to myself, *that* should take care of the heat!
When I bent it, the outside of the angle got all gnarly and full of
fissures from the stretching. So I stopped at a 45 degrees angle.
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