Got an UltraFire C8 last December from Banggood. Some time ago, I was lubing threads and checking the inners of my flashlights and I discovered that the C8 came with a hollow pill. I used it very little since then, because of my fear of frying the T6.
I got some time today and went to a friend’s shop. He built a bronze plug to solve the thermal issues. He made another one for a smaller XR-E bike light that had the same problem.
After re-assembling the flashlight, I confirmed that now the body gets hot enough very fast, so it works as expected. Now I can use the flashlight without fear of burning the T6.
Photos:
Mounted at the end of the head during soldering. Thermal paste under the star.
Bronze… that’s what my friend said: copper alloy with some phosphorus. They use it to build some industrial parts. I had the idea to use aluminium but he had that bronze piece only.
He did the hole in the middle for the cables :~ … later I explained him why it wouldn’t work so he did the correct holes at the sides.
As long as it's metal, it really doesn't matter. There's no measurable difference in light output which is the only thing that matters. If there were a significant difference in thermal capacity it would show up in the light output.
Similarly it's been proven that the Gen1 Sinkpads with the divot in the backside right below the LED, and the Gen2 Sinkpads with the recessed center thermal pad, don't affect light output either. So, I think it's safe to assume based on that that a hole in the center will not have any negative effects either.
Some stuff matters, some stuff doesn't. A dielectric layer under the LED matters. Most of this other stuff just doesn't.
