djozz, I'm really looking forward to your crash test. :)
It will come to life in my Small Sun ZY-C10 (aspheric thrower).
@Hikelite: I soldered it with some pressure, so there was a lot of solder squeezed out.
Did it require any work to get in on?
Nope, none at all. You just have to center it by hand when reflowing. But the solder pads are almost identical.
Wow - I gotta try this... Mostly have been switching over to XP-E2's because the lack of a copper star for these XRE's.
Subscribed! 
Nice! I was wondering if that would fit, and there it is. :party:
I predict some very hard driven XR-E throwers are about to appear
Dedoming it and removing the ring next?
it would me easier to just dedome xp-e2
I tried that, doesn't work with the C10, so the dome will stay in place. Also, it's a rare EZ900. :)
Velly interesting.
I did the test, and because the results are not that spectacular, I will not work it into nice graphs, but just give the summary 
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I had these XR-E's leftover from two identical small Spiderfire flashlights that I modded, I hoped that they would perform the same:
I reflowed one on the MT-G Noctigon, one on a aluminium 20mm star (I think it went well), screwed the boards on plenty aluminium with Arctic Silver 5 in between. I soldered the +-wires together, so that during testing I could switch between the two leds by just re-clamping the minus:
The rest of the set-up I described in the crash-test threads that I started, basically I connected a power supply directly to the leds. I put identical small OP-reflectors on top of the leds (no glass lens this time) to measure ceiling bounce lux. The test results ( ) :
Summary:
-Up to 1.5A the two leds perform very similar, so I think (I hope) that any differences between the two boards is mainly caused by the type of board and not by individual differences between the leds. But the differences in the tests are not that huge, so feel free to disagree on that. Oh, and I am not going to swap leds and boards to do the reverse measurement to check it.
-the peak output on the aluminium board is reached at about 2.0 Ampere, and is 300 lumen out the front of the reflector, the peak output on the Noctigon board is reached at 2.4 Ampere, and is 360 lumen OTF of the reflector. That is a gain of 20%. If you compare the output at the same current (at 2.0A which is the peak output current on aluminium) the gain is 10% when using copper.
So according to this quick and not very accurate test the benefit of using a copper board for the XR-E led seems not to be as great as with the XP-E/G or XM-L led. Not quite noticable by eye that is, for the real lumen hunter any gain is good of course 
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Definitely not the same gains as the modern emitters, but it’s about 20% or so. Significant if you plan on pushing an extreme thrower. I wonder if an XP-E on copper will do better?
I still think XP-G2 on copper at 4.5A ish makes one of the highest surface brightnesses. XM-L2 at 6A+ probably close behind.
Excellent work djozz! This is very helpful - you identified the peak amperage, and bottom line like you said, a 20% improvement at that peak amperage. Of course there will be variations.
Do you know if these are EZ900 or EZ1000's? And if they are Q5's or R2's? Probably Q5's because of what light they came from...
They look like EZ1000's and could be any bin (and pretty sure not R2). I just hoped that the bin would be the same between the two, since they came from the same source.
If the behaviour of the xpe isn't much different from the xpe2, it does better (see Match's test on the xpe2 on copper vs aluminium).
Thanx for sharing the results djozz! :bigsmile:
I think I know now how to mod my Jacob A60 and other XR-E lights.
Oops, I meant XP-E2.
Too bad . . my sinkpad samples didn’t include MTG copper so my de-domed XRE may stay on alum.
For it’s die size the XRE has by far the largest heat pad so an aluminum mcpcb is relatively easy to drill for a 12 or 10awg solid wire. Easier than that though is using a Dremel to grind off the plus/minus pads on the bottom and solder it directly to copper. The pads on top are large and accessible for the wires.
And how about cooling an XRE via the metal ring on top?
(Yes, ancient topic about ancient LED, but…)