You believe it's nickel not chrome? If it's very silvery should be chrome.
Brass can be a bit better than 115 W/m-K but then it would get more soft than the common one and pose the same copper threading issues.
If the pill is only Cu in time the gold plating on the inside will go off and a nickel layer will be exposed, assuming the gold layer is very thick, otherwise play with it several days and should come off from screwing. If it does not come off then it's a solid CuZn pill because there's no plating.
Thanks Overclocker for your response re: switch circuit. I did not notice the protrusion of that black plastic.
As said before, the circuit at the tailcap was a buffer circuit for the switch. Quite amazing to notice also that a SOT-23 sized mosfet could pass >= 6A of current.
The 1st time I knew they’re using chrome plated copper, I was a bit worried on the durability of the threads. And after seeing the pics, I was suspecting its not pure copper but, brass or some kind of alloy of copper. Then, another concern came up, which is the inherent higher thermal resistance compared to aluminum alloy variants. Hope David of thrunite would mind to explain this. No worries of thread durability but, heatsinking efficiency is another concern.
it’s not 6A through the tailcap because there are three cells in series that goes though a buck circuit so it’s less than 6A
it’s unlikely to be pure copper because copper soft and the walls are thin. and copper is quite difficult to machine, it gums up your bits. i used to machine pure copper waterblocks for overclocking
Tom, did you happen to check continuity through the thermal pad when you were de-doming? The mcpb in my Solarforce S2200 looked pretty much just like that, 32mm copper star but no continuity through the thermal pad. When I sanded it down there was indeed a layer of dielectric between the thermal pad and the copper disc.
That disc is now sanded smooth on both sides and sitting under a 20mm Noctigon with XM-L2 U2 1A at almost 1500 OTF lumens and 338Kcd in a MAXToch SN6X-2X.
I posted a couple of times that TN31's has continuity through the thermal pad of their emitter base on the stars (no apparent dielectric layer) - I did test this, but no one responded from what I recall. I believe AlexGT was the one who posted his detailed mods, one of which was filing down the thermal pad (step #8 here: https://budgetlightforum.com/t/-/17637), which I thought there was no reason to do. So, not getting any replies, not sure what went on - maybe he got an earlier version that had a dielectric layer? Not sure... Here, post #52: https://budgetlightforum.com/t/-/17637#comment-395402. Post #39 has the first mention of it and pics to show it. What do you think?
I did not do a continuity test on the star before I filed it a little with the dremel, it looked from what I could see that there was something there, but I could have been mistaken and there was no need for filing, but after seeing the kapton tape on the other side I just didn’t trust it to be perfect anymore, I wanted to make sure
Probably the same as what you measured. :bigsmile: and my luxmeter is not quite accurate. The most important is that TN32 gives amazing amount of light and throw for the price.
Ahh - thanks Alex! That explains this long-standing mystery - at least in my mind . The Niwalker has a big, thick copper star, but it does have the dieelectirc layer so failed a continuity test with the center thermal pad. I had a lot of trouble getting the reflowed LED to sit down nice after reducing the center thermal pad - maybe I took too much material off so was a bigger gap to fill with solder paste.
These ThruNite's have one of the best designed stars. Sorry for goin a little off-track here...
I’d be interesting to do a direct comparison between a modded TN31 and a stock TN32, specifically on the output sag, which can imply which light has better thermal characteristics. I’m slightly disappointed that the pill isn’t pure copper, as brass and copper have very different thermal properties. Even aluminium has a better thermal conductivity than brass, as overclocker pointed out.
Another important aspect of designing a high performance light is the specific heat of the heatsink, which measures the amount of heat required to raise the temperature of a material.
Most reference sources indicate specific heat in J/gK, but we need to convert it to in terms of volume, because the volume of the pill, whether it be aluminium, brass, or copper, is constant.
My buddy I grew up with who now lives in CA wanted a great light. I seen your review and told him to get this one. He bought it from Illumination Supply using coupon code HappyHolidays and got it for $143 and change. I told him that’s the cheapest place I know of to buy it. He was going to buy a Vinh K40. But I told him for his purpose and this is probably the best flashlight he will ever buy it will serve his needs and then some.
. The Niwalker has a big, thick copper star, but it does have the dieelectirc layer so failed a continuity test with the center thermal pad. I had a lot of trouble getting the reflowed LED to sit down nice after reducing the center thermal pad - maybe I took too much material off so was a bigger gap to fill with solder paste.