And if run the boards at 1050mah a flat aluminio piece will work ? I was thinking about make the alumio pice a little bit bigger than the boards. My problem also is, i cant find a heatsink with this mesures in europe 305*358MM so i will have to run the boards a little bit cooler to use a flat aluminio piece what you recomend ?
That was my keyword...
Simply glue a few c-channels to the sheets backside. I've used cheap e3ay thermal glue and epoxy only
for the last few centimeters to keep the channels safe in place. This works great!
The one below is 14x 24", made of a 3mm alunimum base plate and eight 10x 20x 10x 2mm c-channels and tested with 6 COB's and 430/670nm mono's running at 150w. The heatsink stays below 50°C even after 18h, passively, only with the small breeze inside a 3ft² chamber.
BTW,
even if you find cheap heatsinks, shipping costs will double the price.
Another old shot I've found but only with the 6 COB's @700mA.