MEXICOWANDERER wrote:
Hah I forgot to mention this is Mexico.
"Surplus, spare, extra, unneeded" copper or aluminum? Shirley you jest. Place a strip of copper on a roadway, count to ten. Then count the number of scrap metal "chattareros" racing to be the first to snatch it up. Bushes, trash cans, under the kitchen sink, every place is scoured to find scrap copper, aluminum and steel.
Copper for pipes does not exist brand new. Plastic, rules.
I found a 17" long 3 lb. heat sink in an electronics surplus store for a 3 X 100 watt LED project I am considering. Cost is 25 dollars plus considerable shipping.
I did some searching on the internet by Google for appropriate 10 watt heatsinks and ended up dizzy. Something pre-drilled would be great.
But something smells like month-old carp about the whole LED lumen, wattage, and heatsink subject. Professional re-sellers like mickey-mouser recommend using heat sinks far and away (by magnitudes) larger than what I see as being used in "advertised for "X" wattage "X" lumen plates". Even Chinese websites show low wattage flood lamps with humungous size heatsinks. The fixture price is not cheap.
For the "Big Lumen Project" I am damned near ready to throw in the towel and buy a 400 watt Metal Halide fixture. I simply cannot find any way to verify 4 100 watt LED plates would stand a chance to supply equivalent lighting. The fixture is going up twenty three feet in the air to light up a warehouse size store. The LED promise is enticing, supposedly much less wattage (try FIFTY DOLLARS A MONTH SAVINGS in power if the LED hype is true). But something is wrong with the tinker-toy grade experiences I have had with the smaller plates. It is embarrassing to find out "You Have Been HAD Bro'"
Pretty good chance that you already HAVE some aluminum on hand..
If you have any soda or beer in a can, then you HAVE a heatsink...
Alternately if you have a can of any vegetable you already have a heatsink (like a mentioned STEEL will work as a heatsink in a pinch, just not as good as aluminum or copper).
This is one place which you do not need a fancy factory made heatsink, all you need is a bit of metal to add to the plate.
In reality a piece of aluminum, copper, steel measuring about 1"x1" square should be able to dissipate about 8W of heat (in free air) if you make some cuts into the edges and bend the cuts open a bit (think like making a "V" or "Y" shape).
I have seen many small heatsinks that were designed for power transistor or IC outputs of 8W no bigger than 3/4" x 1" that had a "U" shape with fins simply made from the side cuts.
While homemade heatsinks may not be ideal they are cheap and plentiful if you think outside the "CAN".
The idea is to keep the chip cool, they can be run "hot", basically temperatures cool enough that you can handle it without getting burned should be OK to use.
Start with a bigger piece of scrap metal and cut it smaller monitoring just how hot it gets, pretty good chance you will not need a big fancy factory made heat sink.
In my testing I started on the low end with 9V then increased the voltage (current will rise and so will the heat which needs to be dissipated) to 11.2V.
At 9V, I barely felt any heat, at 11.2V my heatsink got warm to touch but not hot enough to burn (keep in mind I was using 3x4 inch 1/16 aluminum).
To think, in the states I used to buy those small heatsinks at my local Radio Shack for $.79, sadly they carry very few parts like this now days..
BUT, you can get some
HERE at 3 for $1 (I think they do have a minimum order so you might need to read up on that).
Or other ones they have
HEREThere are plenty of other options for buying electronic related parts, Ebay is not one of them... Not sure how they handle the Mexico thing but I will give a few of the ones I have used or am aware of.
MCM ELECTRONICSALL ELECTRONICS (listed several from this website in my links above)
SKYCRAFT SURPLUSHALTED ELECTRONICSSearch for "electronic surplus"
HEREAlternately ANY tossed out computer, TV, stereo, even brick power supplies will have some sort of heatsinks which can be repurposed.
As a caution, if using copper then you would want to use a silicone or mica insulator between the copper and the chip.
The plate on the chip is aluminum.
Copper and aluminum are not the best of "friends" electrically so you need to keep them "happy" with a non electrically conductive product but it must be able to transfer the heat.