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Putting together an led light for my algae tank; input wanted!

So I am putting together an led light for my algae tank (a 50 gallon). I have 4 6500K led boards (25 watts each) that will fit beautifully on a 2" by 48" heatsink from heatsinkusa.com. I want to get the heatsink drilled and tapped so I can easily mount the led boards. I am going to ask heatsinkusa for a quote, but before I do, I'd like some input.

First off, where could I get a 4 foot aluminum heatsink drilled and tapped locally, just incase I decide to get it done locally.

Second, how mould you go about mounting such a light to the tank?

Third, what should I use for a splash guard and how should I mount it to the heatsink? I thought about using a clear acrylic tube cut in half the long way and screwing it into the heatsink, but it turns out that the tube cut to size would cost more than double what the heatsink costs! Any other (cheaper) ideas?

Thanks!
 
I know you didn't ask this, but I wouldn't bother with drilling AND tapping, I would get some stainless steel screws, and drill a hole using a bit that's a bit smaller than the screws. Then screw them in by hand, the screw should make it's own threads due to how soft aluminum is.

2nd... depends upon how you want to mount it. Cheap and easy, just make some hanging brackets from galvanized pipe, you can attach it to your stand with clamps. Alternatively you could drill a couple small holes in the aluminum fins at either end and hang it from a ceiling (or any other hanging bracket, i.e. cheap and easy solution). One thing I would not do is attach it directly to the tank top, 2" thin it wouldn't take much movement to put it at a slight angle than splash into the tank!

3rd. Use a flat piece of acrylic (or pieces), then weld on little flat tabs to the side of that at random locations (think a square U shape), or just along the entire length if you want complete splash protection, drill holes in those, use stainless steel screws attach directly to heatsink. You should be able to get really thin stuff at Home Depot or what not such that you can score it with a carbide blade (they sell them too) then just snap the size you want.
 
While I agree with Mike about the stainless steel screws threading it would probably be the "easiest" solution.

Not sure what LED's you are talking about but RapidLED ( http://www.rapidled.com ) (Local in Burlingame and they allow you to pick up items) has a 48"x 1.4" heat sink. They offer drilling and tapping themselves but it's for regular LED's. Give them a call and they might be able to do custom sizes?

If you decide to go with the 6" version it has a splash guard that comes up. I'm rocking a 6" x 12" for some (ok, a lot of) UV Supplements over a frag tank. It's a nice little system really and worth a look.
 
@Lokii_37: Great idea, but I don't think those are big enough. They would need to be 2" in diameter to work, and I don't know of any fluorescent lights that are big enough that they would need such a large cover.

@sfsuphysics: Fair point. I went ahead and ordered the heatsink with no extra machining. It will be easier for me to drill the holes myself and then just force steel screws in. I want to mount the light directly to the tank because all my other lights will be mounted that way. My DT lights are made by buildmyled.com and they have nice little mounting feet to hold them onto the tank. These lights I'm building will for my extra large fuge/ats tank, which is acrylic and has eurobracing (if that's the right word for it) and smaller openings, so it would be very difficult for the light to fall into the tank. Maybe I should just bend some acrylic into 90 degree pieces and attach them to the heatsink via some spacers and screws... I guess I'll end up doing as you say and cutting long strips of acrylic, bonding them together with weldon, then screwing them into the heatsink for a splash guard. I just wondered if anyone could think of something else. But that will be fine.

@Tenny: The LEDs I have for this purpose are 1 watt Luxeon Rebels. 21 of them are mounted on an ~11" x 1.75" board with integrated drivers. I have four of these boards and a power supply suitable to power all four of the boards. Since they are 1.75" wide, I cannot use a 1.4" wide heatsink. I called RapidLED today, and they said they do not do custom widths. So I went ahead and ordered the heatsink without any holes drilled form heatsinkusa. I do love how RapidLED's fixtures look when they're done right though :)

Thanks for the input everyone!
 
While I agree with Mike about the stainless steel screws threading it would probably be the "easiest" solution.
HA! Depends what you mean by easiest, paying someone to do it... ok sure that's easiest :) But if you did it yourself, good lord no, that'd be the hardest solution (which is why drilled and tapped heat sinks tend to be a lot more than bare ones). Of course having the right tools helps make jobs easier, with my drill press I can do the 100 holes or so I need for my heatsinks in 10-20 minutes, perfectly straight holes to proper depth :)
 
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