Looking good so far.

Are you at all concerned that a slight warpage in the base plate will cause an airgap and render that portion of the sink less effective than those next to the welds?

Looks solid. How many watt are the 136 leds ? I would maybee think of putting another fan to help out with the heat as you may find the transfer lacking from the 1/4 sheet to the 1/8 flat,

Cant wait to see it running over a tank should produce some good light.

There is no way that these will warp, as soft as aluminum is it will actually take a little more heat to warp . Total watts of the LED would be 408w @ 100% which I doubt I will even get close to that.

I am looking for a product I heard about that is similar to Silver Solder. It a matter of heating it up & pouring it in to fill any gaps.

Hey Grizz check out Loctite® Fixmaster® Aluminum Liquid.

it should get the job done and its easy enough to find.

Dude that's the exact stuff I was talking about just couldn't remember what to was called or who was the maker. THANKS

Grizz, I appreciate the crafstmanship and the work you've put in so far but I see a potential problem with the fabrication of your heatsink; with the fins only being tacked a few times there will be barely any thermal transfer between the main plate and the fin. A continuous weld would have been much more effective (or atleast a heavier stich-weld) Do you have any plans to solder/braze the joint between the fin and the plate? If not perhaps using thermal adhesive would have been more effective? Simply having the fin touching the plate (probably a bit of a gap now due to warp and drift from the welds) will not be much better than simply a bare plate.

On a somewhat related note, if you can build a plenum to spread the air from the cooling fans across all the fins they would be much more effective, rather than just cooling the four or five channels directly below the fans.

I really don't want to rain on the parade, just trying to help prevent burning up some expensive LEDs after the plate soaks up all the heat it can and reaches critical temp.

Edit: I just re-read and see that you plan to solder the fins in place. Looks like you've got it covered!

Wait for it...

I'm looking at your first layout of colours. The white seem to be mostly around the edges and the blue/royal blue/other colours are in the centre area. Wouldn't you want to mix them up a bit to even out the colour, or is there a particular reason to have the whites along the edge?

Really looking forward to seeing these LEDs on your tank :)

There is a row of XP-G Cool Whits down the center, they are the brightest of all the whites. They are my High Noon kit & wil be on at the highest % from 11:30 - 1:30.

I am think of adding a 3rd fan to each heat sink but even with just 2 you can feel the air flow at both ends of it.

Ahhh! That's what the HN means! There are so many code words to this LED thing ;)