Hi, I have a project in mind and need some XM-L U3 on a copper PCB, I saw that led-tech.de had them but they are not listed anymore; intloutdoor has U3 but only on aluminium PCB, I asked HANK and he says he doesn’t have U3 on copper…
Also just the empty XM-L copper pcb is enough for me, I can do reflow on my own if I can get the pcb.
Any ideas on where to look for?
Just send an email to led-tech, it should be possible to buy the PCB without LED.
If they do sell them let me know ill buy some 
Many thanks for the links!
I have contacted led-tech, but I’m pulling the trigger with DX’s. I want them to mod my KING with U3, may be I will have to shave the PCB Star a little bit to fit but they will work fine.
Thanks again!
You may want to hold off or cancel that order. I read somewhere recently that no one has yet found a copper star (besides led-tech.de) that is thick enough to conduct the heat path to the edge of the star for it to be of any benefit over an aluminum one. Those thin Chinese copper PCB’s are apparently to thin to be of any advantage over an aluminum mount.
What does thickness have to do with thermal management if it’s a star? The only thing it will affect is if the edges of the star will be touching the walls of the body.
FWIW, I ordered 5 XM-L U3’s from fancyflashlights and just got an email to inform me that they are out of stock on U3’s at the moment. To bad they dont have online inventory status… such a waste of time. Time to refund my PayPal.
It apparently needs sufficient thickness to transmit the heat through the entire surface area to be of any advantage. If I find the article, I’ll post the link.
Okay thanks, because I thought that in terms of transferring heat, a thinner star would be better, but I guess what you’re saying is that there’s a point of diminishing return. It does sound plausible.
I purchased a pack of the DX copper PCB and tested them side by side with Aluminum ones. I attached a fine bead thermocouple next to the LED. I measured no significant difference in heat transfer / temperature driving them both at 3 Amps with a XML U2. Both were attached to an aluminum heat sink. I then carefully machined the center portion of where the LED solders, so I got down to the copper base. Soldered it, and did the experiment again. Overall, the LED with copper base ran 15C cooler. If anyone wants to try this, you have to get rid of all the dielectric material between the base copper and the LED.
Cheers!
Are you guys sure those DX copper stars are copper and not brass?
Just what I needed! Thank you!
The ones I got were definitely copper. I would imagine if they were brass, the thermal performance would be worst than aluminum. I didn’t see that when I tested them.
Two different shipments of them and they are indeed copper.
OK, I’m not buying them then. Thanks for the advice, better to know now instead of after reflow!
at led-tech they say: Currently is the U3-Bin complete sold. Copper PCB without leds are currently not in Stock. I can only offer U2 on Copper PCB.
I'm going to stick with aluminium PCB then...
Build your own copper PCB? OL managed to do so. Brass would also work (better than aluminium imo) because you can leave the dielectric layer out. Thats the bottleneck. Problem with aluminium: its not easy to reflow an LED to aluminium.
I thought about it, I’ve done that before with just one LED, but centering three LEDs… I know I will mess it up and ruin the flashlight.
True about the bottleneck with aluminium star, this image from led-tech is very ilustrative:
