The flat base is 26.5mm across.
thanks ,so its better to use 32mm led pcb
Yes, definitely makes clearing the solder blobs easier. You’ll have to fill in the cavity in the stock heatsink shelf or flip it over and sand/lap it flat though.
i think i will go with copper replacement of the heatsink,ofcourse with that heatsink you might eliminate the clearing problem whatever size pcb you use.
Certainly a good idea to go with one of Nikolas pills, don’t see how they would help in the clearance issues though.
The distance between the solder pads on the mcpcb compared with the diameter of the flat base on the reflector is what is causing the issues. The 32mm pcb has solder pads that are no longer underneath the flat base of the reflector so you can essentially solder the wires on as thick and fat as you want. 
For smaller pcbs you’ll have to resort to making very flat solder joins and keeping the wires relatively thin or resorting to thin copper tabs to make the connection. Bit more tricky if you haven’t done it before.
I used the 32mm Noctigon but the reflector still overlapped about 1/3 of the solder pads, similar to the photo in FmC’s build thread.
I still had to file the reflector and solder carefully to get the reflector all the way down on the PCB.
did you used the stock heatsink or the copper one ?
I made my own using a copper disk.
ic,thank you guys for the tips.
I took a bite at $27… not a bad light at all… I’m thinking getting a second one for gift 
Here is some pic. using 20 mm Noctigon , in this case I am using 20AWG wire, and small centering ring…… Kapton tape in this mode is ,a must have over the solder points and on the bottom of reflector
And the final result look like this !!!
Show as some beamshits please?
Are there any artifacts into the beam?
I dont have good enough camera to take a nice beamshot but I will try to capture best that is possible.
There is no artifacts,only one thin ring around well defined hotspot….
I’m pretty sure that ring around the hostpot is an artifact created by light bouncing off the inside of the front glass lens and then being reprojected by the reflector.
I suspect getting a good AR lens will almost completely eliminate it, that was certainly the case on my first courui build.
I think that ring is not light bouncing off the inside of the front glass lens, rather the light reflects from the opening of the reflector because the LED is in the line with him in this case, and considering that dedomed emitter is making 360 angle, it is most likely a reflection of the that opening. That is just my opinion…
My wife has a habit of hanging things on every open wall she can find, not a darn white-wall in the house.
The basement wall gives an idea of the beam profile though. 5-6 feet from the wall, camera on auto. First photo on low, second on moon mode. No idea why I put a moon mode on this light.
I initially thought so too, and we may be talking about a different artifact entirely.
Just saying when I installed the Uclp AR coated lens it cut down that distinctive sharp ring around the hostpot so it’s almost invisible. It also made the remaining artifact less sharp. No other changes to the light.
I’ve seen it happen on other lights when upgrading to AR too but with the courui and the acrylic lens it was the most apparent. There’s quite a lot of light being bounced back into the reflector by your average glass lens and it has to go somewhere. The spill ring to the sides of the light are also cut down significantly when AR glass is installed, but that’s a more obvious and logical effect.
Has anyone else noticed beam differences after swapping out standard glass with AR?
Of course that AR lens make a significant difference, here can be seen what is the difference between stock Courui and Acebeam K40M AR lens…
Yeah but specifically how it affects the beam artefacts is interesting. Does the Acebeam have a moonlight mode? That can be really useful to study how different parts of the reflector and lens contribute towards the final image.
For example on my courui with the AR acrylic lens, the images seen in the reflector have two distinct colours. Straight LED colour for any light that has simply hit the reflector once and exited the light. And deep purple/blue images for light that must have rebounded off the inside of the lens (hence the colour cast) and then been reflected a second time by the reflector. If you move the light around while looking in the front you can see how those two factors interplay to form some of the artefacts.
Then by specifically looking at the light from the angle that you would expect to see the ring artefact (if the ring forms at 15degrees then study what the reflector image looks like over that angle range). Essentially you want to look at the light from that angle and see what could be contributing towards that artefact.
The ring I’m talking about starts just before the corona begins to fade in, so look at the light from that angle and see what jumps out at you.
In my light I don’t see any light hitting the rim of the reflector that could be contributing to a ring artefact around the hostspot. I do however see a distinct image coverging/forming in deep blue right around the angle that I saw the ring artefact. Before the AR lens that secondary image would be A: Much brighter and B: The same tint as the primary bounces.
So in that case it’s very hard to tell them apart.
I’m not saying that’s exactly what is going on in your light, maybe it’s something completely different contributing to the effect you see. But this is a really good way of finding out, also you could try the light without the lens in place and see if the ring is still there. Would definitely rule out any involvement the lens may have.
It’s quite fascinating how the different parts of the reflector and lens interact, moon modes rock!
I submit my suspect for consideration. I tried to make a video but my phone wasn’t having it. 
Likely culprit marked in red in this image.
It’s very blue, so that means the light has to have hit the lens at some point. Also as you move your head towards the center of the hostpot this image forms and then disappears again quickly, exactly what you would expect to form a ring shaped artefact in the beam. Gradual changes in the images seen produce gradual and smooth beam artefacts so all of those can be eliminated.
Finally it’s likely the brightest blue artefact there, though again because of the AR coating it is significantly dimmer than the parts contributing towards the main beam corona. See if you can spot something like this in your light. Hunt that ring!
1100 + METER SHOT WITH COURUI ! ! ! by NikolaS