LED Heatsink Questions

[CleverBs]

So ill give you a bit of info to start with about the build I want to build 2x 24bulb fixtures from rapid LED for my SPS reef:

75g Standard
48x Cree 3w LEDS
SPS Tank
Fixture Will Be Hung In a Canopy 6-8'' Above the water

I want the lighting to fit properly and distribute light in the right way. I dont know how wide or long my heatsink should be. This is my main problem. I am ready to buy the equipment but dont want to tell I have found everything I need and the heat sink is the only missing part. ALSO need to know what degree lens I should use 60 or 80?

ALSO whats

• 
  Anodized?
• I would like a heat sink like this Drilled but I cant find any that are in stock anyplace.

 

[Saratj1]

aniodizing is just an electricaly applied powder coating, may inhibit some corrosion not sure though but wont hurt the heat transfer. Not necessary but looks nice and wouldnt hurt.
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I am doing a similar project. Here's the heatsink I'm using:

And here's my link to a thread on my build. I haven't done much yet as I haven't got some parts from china in yet.
http://www.aquariumadvice.com/forums/f20/diy-budget-led-experiment-200531.html

 

[CleverBs]

aniodizing is just an electricaly applied powder coating, may inhibit some corrosion not sure though but wont hurt the heat transfer. Not necessary but looks nice and wouldnt hurt.
eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
I am doing a similar project. Here's the heatsink I'm using:

And here's my link to a thread on my build. I haven't done much yet as I haven't got some parts from china in yet.
http://www.aquariumadvice.com/forums/f20/diy-budget-led-experiment-200531.html

they arnt up anymore and I dont see any that will work for my build.

 

[Saratj1]

I saw they didnt have that size that I got anymore, but keep an eye out the size i got was 600mm x 140mm x 25mm, so 23.6'' x 5.5'' x 2'' , it was around $40 shipped, not drilled. I also got a narrower one and pre wired strips.

 

[CleverBs]

would a 5x12 heat sink work well?

 

[Saratj1]

For how many LEDs? It wouldn't be enough for 48 x 1w. I'd say Maybe 20 x1w , 4 rows of 5, or 6

 

[CleverBs]

I found a site that I can order any size I want thats made here in the USA! so ill be getting a 2 - 6x16 fixture does this sound good? each fixture will have 24 3w LEDS

 

[angelvelez87]

Have you looked for aluminum ibeams?? I saw on another web site how a guy made a led fixture with it and it looked awesome caise he even putted a acrylic piece as splash guard!! Plus i made my fixture with an aluminum channel very thin though but it works!! If i remember well the ibeams on amazon was $15 for 12" and my aluminum channel costed $4 very cheap and easy to drill!!