Luxeon 5 watt, Leave on Star or take emitter off?

Got my luxeon 5 watt emitters today, should i leave it on the star or take it off of the star? Not sure which way i should do it, but the heatsink i made for it is a 1/8" slab of aluminum with 5- 1/4" holes using 1" x 1/4" aluminum pins for cooling. Surface isn't as flat as i wanted it to be due the me being a newbie at aluminum soldering.

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ufokillerz said:
Got my luxeon 5 watt emitters today, should i leave it on the star or take it off of the star? Not sure which way i should do it, but the heatsink i made for it is a 1/8" slab of aluminum with 5- 1/4" holes using 1" x 1/4" aluminum pins for cooling. Surface isn't as flat as i wanted it to be due the me being a newbie at aluminum soldering.

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Why would you want to take the 5W off it's heat sink? Just bolt it on, or epoxy it on with heat sink epoxy.

The surface of the sink should be as smooth as possible. The more contact, the better the sinking. Try putting a CPU heat sink on the other side of the sink?

Wayne j

I know enough about heatsinks being that i do water cool my pc and all, i'm not sure what kind of heat the 5w will make with 9v, but i've tested all 10 and THEY DO WORK =), I feel that the heatsink i made myself is better then any heatsink i could find for it, its a 2C flashlight, space is limited, i was using 1 of these http://2cooltek.safeshopper.com/67/152.htm?65
for my 1 watt ls, it seemed to fit the 3C i had perfectly. The new one i made has 5 fins that are 1 inch each or around that, and it is soldered together, so it probably has better surface area then one of those. Will keep the emitter on the star and use =)

the slug of the luxeon, if it's like the 1 watters, doesn't actually make contact with the stock heat sink. it epoxied onto the fiberglass coating, so there's two materials it needs to go through in order to hit the stock heatsink. it may be beneficial to remove it, clean the bottom of the slug well and re-attach it to a better heatsink directly.

take into account this is all conjecture, i haven't actually seen nor touched a 5W luxeon.

Well, i did get these from Wayne, and he appears to know what hes doing considering that he operates elektrolumens, the 5 watt star is like that 1 watt star, but the pcb appears to be thicker, no idea why. i dont really want to take it off the the star pcb because there is always a risk of damaging/killing the emitter while taking it off.

ufokillerz,
I "popped" a 5W a couple of nights ago- be sure and note the polarity if you do /ubbthreads/images/graemlins/grin.gif . The 1W and 5W emitters are thermal epoxied to the metal sinks. Normally, the epoxy will result in a thin, electrically insulating layer. I wouldn't clamp the emitter or you could get a short. The "slug" on the back of the emitters (appears to be silver-plated copper) is not electrically neutral- Lumileds warns about this. I have now "lapped" two emitters, a la cpu sink, Arctic Alumina epoxy'd them to their new sinks, and both worked fine.

Larry

Larry

I have removed 1W emitters from the star board no problem, but theres a risk in everything and 5W emitters are a lot more pricey then 5 watt emitters.

The 5w emitter is bonded directly to the alluminum heatsink with a pinkish color adhesive, the fiber board is attached at the 6 points of the star with the same stuff. The heat sink is solid alluminum (very hi-grade) as far as I can tell. (chopped it with dikes)
Best desolder the two main emitter connectors first, so no damage is done to it while removing, since the two pieces are not connected other than the two main solder points.
I have to agree with Wayne and feal it should be left intact (grind to fit) then bond to additional heat sink to help keep it cool.