LED fixture

I agree that using thermal adhesive is easier and it's not a big deal to change LEDs if that need arises. Drilling and tapping is definitely better for heat dissipation from the star to the heatsink. I've drilled thousands of holes in aluminum (not just LEDs) and have never broken a drill bit or a tap. Aluminum is a very soft metal compared to steel which is relatively easy to break either.

I repectfully disagree. The LED is only pinned down with pressure on the star at two points with screws. Sure it has thermal paste under it but I feel the thermal adhesive is a more solid, even and heat conductive surface across the entire star. Would you see a noticable performance differance between screws and thermal paste compared to thermal adhesive? Probably not.
The ease of the built with thermal adhesive is much quicker, cheaper (no screws, washers, taps or drills to buy) and I didn't want to worry about thermal paste which stays moist over the water where the adhesive actually dries solid.
I actually broke to cheap 8-32 taps from Lowe's trying to tap holes to mount my two heatsinks together with angle iron. I was using the correct size drill and cutting oil too. The aluminum that those heatsinks are made of is very hard. But the drill and tap from Lowe's for only $5.00 was probably to the highest quality either. If I was going to do it again I would go to Aubuchon's and purchase Irwin taps and drills.
 
I think it's all just preference. I think either way works fine.

+1 on buying the right tools for the job
+1 on buying not cheaply made tools
 
i think the difference is minimal but if i were to give an edge to anything it would be the screws, the back of the surface is flat so two points will apply clamping pressure across the entire area

i have used both the lowes tap set and a titanium tap set and tap a #4 and havent had any broken taps since i broke a crappy black bit
 
I drilled and tapped AND thermal adhesive'ed my LED's. Mine is only a 9 star light (its over a 4 gallon tank...) so I didn't want to worry about a fan, so I was looking for the most heat dissipation as possible. The fixture ran all day today (super low, but still for 8 hours) and it is colder to the touch than the tank glass. Also, if you are going to drill and tap, a couple tips:
- Have multiple drill bits! I have machined many different parts, mostly automotive parts, so this wasn't my first time. I still broke one of my titanium bits.
- Have multiple taps! Same thing applies from above. It happens, taps break, especially when they are so small. You move your hand side to side just a tiny bit and SNAP
- OIL THE TAP! I see so many people use taps with no lubrication, then wonder why they break taps, or why their taps are dull after a dozen holes. There are specialty tap/cutting oils out there, I use WD-40 because I always have it around.
- Go slow with the tap. On this build, and on other aluminum parts, I find I used the least amount of effort tapping when I turned the bit in a full turn, then backed it out a half turn, repeat through the whole hole. It takes more time, but its easier on the taps.

Just things that have worked for me. I'll have the shots of our new fixture up tonight!

Cheers
...Skeeter...
 
I screwed mine and spent a day drilling and tapping. I used a drill to tap them, and it worked fine. In the end I glued hem down, because I found that if a hole is alittle off, it wouldnt hold it flat against the heat sink. I had made a template, and it took me 20min to glue 72 LEDs. I would never drill something unless is was a Nano.
 
part of it is the fact that you used the #6, there is a little more wiggle room with #4, i probably have to redrill less than 5% of holes and im pretty fast and loose with the drill
 
does anyone recommend a led amount for a 40breeder? I'm thinking out with the halides. I just don't have any idea about led/gallon ratio.
 
I have made some progress one of the 2 heat sinks have been drilled and taped. Here is a picture of where I am. It has been a learning progress since I have never drilled and taped anything. I broke one drill bit but since then things have got better. At first it was taking me 10+ min per hole, but the last hole I did took me about 2 min. So I am thinking another 1-2 hours of work and the 2nd heat sink will be done. Then I will just need to wire them.

c5e7532d.jpg
 
Looks good. I just finished a 2nd one for my sons Nano. I posted pictures some pics on my my LED build thread. Keep up the good work.
 
does anyone recommend a led amount for a 40breeder? I'm thinking out with the halides. I just don't have any idea about led/gallon ratio.

It has to do more with LED to surface area in a shallow tank like a 40 breeder (to avoid spotlighting) if you plan on hanging the fixture close to the water. The higher you want to hang it the more leds (add optics) closer together as optics close the lighting pattern and again can cause spotlighting.

You want the leds spaced no more than 2" apart, and 3" per row without optics. I'd guess bare minimum for coverage would be about 24, but you might want more like 36... 48 would be overkill IMO
 
I did. Some of the paste came out from under the star. What would be the easiest way to clean this off?
 
Rubbing alcohol wont mess up the lens like acetone and it take the paste right off. Just remember that you only want to use a very small amount of the paste under the LED.
 
Paste is thermal glue, and then there is no need for screws to hold it down. Usually it comes in two parts that you mix, then apply. Thermal grease is just that. Just grease. You will need to secure the LED's to the heatsink some other way, as this will not stick them permanently to the surface. What is the product name that you have?

Jordan
 
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