I was at Lowe's a couple of days ago looking through the plumbing parts for a suitable piece to use for a spacer in my triple build. I'm using a Convoy S2 and the 20mm Nichia triple from KD for this project. After about 30 minutes of browsing, I located this "3/4 PEX test plug": it's a brass piece that looked suitable, only about $2, so I bought it.
On opening the package, I measured the plug and found some interesting dimensions:
The OD of the head is... 20mm - Convenient
The OD of the narrow portion of the plug is... wait for it... 16mm!
I used a dremel to cut just above the lower ridge on the plug and the piece seats perfectly into the S2 pill, while the 20mm PCB fits onto the flat surface perfectly. And it's brass, so this piece can be soldered directly onto the pill, for maximum heat transfer. If you have a copper PCB, it could be soldered as well. I assembled this temporarily using the aluminum PCB, Fujiked to the plug, and the plug pressed against the pill by threading the pill in. Even with the non-optimal thermal path, this does an excellent job of transferring heat into the body of the light, which became uncomfortably hot very quickly (using a 2.8A driver). I intend to add solder soon to help transfer, and I may eventually reflow the emitters onto a copper board.
This plug is hollow, but it still has a lot of mass in the head, and the walls are fairly thick. The machining process leaves it tapered on the inside making it very easy to drill out the center for the wires without any special tools or centering issues.
Things to do:
Remove the Fujik and lap the spacer and base of the PCB to improve contact
Fine-tune lip of spacer to ensure level seating against pill
Solder pill to spacer
Possibility? Press/solder appropriately-sized tubing, cap, or similar material into ID of spacer to increase mass and cross-section for better contact to pill
Possibility? Reflow emitters onto Copper PCB: I don't have any suitable high-current cells, and am using a 2.8A driver, with no current plans to upgrade, so I'm not sure this is necessary.
Buy a second one: I have the CW triple-XPG2 from KD as well, and would like to make a second triple for when Lumens are more important than CRI
Nice find! I love these brass plumbing parts for light mods. I have a whole box full of random bits that often come in handy as spacers or improvised heat sinks.
I went back to Lowe's and found a 1/4" brass nipple that has an OD that fits into the ID of this plug very tightly. I was able to cut a short piece, then solder into the plug, and file it down to a flush-fit. This is a much thicker walled piece, and results in the spacer having more mass and a much wider flat spacer-to-pill contact. I soldered the spacer onto the pill, lapped the pill smooth, and re-assembled. The additional brass and solder makes the light noticeably heavier; I don't know how much it helps heat transfer, but it does get hot quickly...
Interesting, but I would think the emitters would overheat on that aluminum mcpcb with an FET driver. (brass heat sink or no)
I’d get a Noctigon triple from Richard and protect my investment on the emitters if I were you, then re-flow solder it to the heat sink for good measure.
I’ve seen these triples pull over 12A, 3400 lumens. Unless that’s a direct thermal path SinkPAD (which I know it’s not because it’s not white) you’re likely to lose an emitter soon.
Edit: See if you can touch the thermal pad extension beside the emitter with one probe and the aluminum base with the other, you’re checking for continuity. About a 99% chance you won’t find it. The aluminum mcpcb’s have a masking layer underneath that pad that prevents direct path to the base metal.
The builds using aluminum boards are being moderately driven, at only 3A. I used the generic 8x 7135 driver from FastTech, and it works well for these lights. My FET-driven build had extra mass added to the spacer, to allow additional heat sinking, plus more surface contact with the pill. It used the DTP Noctigon triple board, and all components soldered for maximum heat transfer. Basically, the entire build is a DTP into my hand!
I just bought the last two at my local Lowe’s… The bin was full of other plugs and fittings and I had to dig to find these. I’ve bought five of these plugs, made three spacers, and they’ve all worked well. Just need a dremel with a cut-off wheel to cut them to the length needed for your host.
Yes, I know. Massive thread bump. But I hope you guys don’t mind.
I made a spacer for my Convoy S2+ using one of these and it works great. Very simple build that only took half an hour or so. For $1.50 I’m happy with the performance.