D4 Titanium!!!

I didn’t quite see what you were arguing before you edited your post, now my answer seems off.

Seems reasonable to think that most of the heat transfer goes though the skin rather than the air granted one don’t wear gloves, but the useful surface area of exchange with the skin on the copper pill whatever way you hold the flashlight is teeny tiny compared to the one you would have holding the AL one with the full body being a vessel for heat, and the whole heat being concentrated on those fins would surely be quickly incomfortable to touch.

I’m still not sure what we are arguing, semantics, physics ?

I have a lot of copper lights, and they have not deformed. If you believe the D4 uses a low conductive alloy, please provide evidence

else, I am happy to assume it is pure copper, and NOT brass. (and I do agree brass is a copper alloy with. very low heat conductivity… almost as bad as Ti :-))
see https://intl-outdoor.com/emisar-d4ti-high-power-flashlight-p-927.html
_Features:
• Copper head (not brass)_

I was disagreeing when someone(s) suggested that aluminum moves more heat than copper (maybe I misunderstood, and the idea was meant to be that the aluminum D4 moves more heat than the Ti/Cu, which I do agree is possible).

I disagree that the copper used in the D4 has low conductivity

another perspective on the TiCuD4 heat management:

The Ti Body with the Copper Head is a major safety improvement. It allows the user to fire turbo without fear of burning their hand. Just hold the Ti Body, don’t touch the hot head, let the light do its thermal regulation thing. :slight_smile:

Since there is thermal regulation, the choice of metal is possibly less significant to the overall heat management of the D4.

On a side note, i was replying to your last message (#67) and went back to read one sentence and the whole answer was completely changed again, this is very confusing for the sake of the train of though going though the thread, i agree (i don’t see the safety point though) with your post #67 22:46 UTC time 7 of january 2018 version :smiley:

sure are a lot of brainards in this forum! I love reading them!

I’m waiting for Mr. Peabody’s take on it. :student:

No.

The most common “pure” copper used for machining is TeCu, barely loses any proprieties with 93% conductivity of actual pure copper and it is well over aluminum alloys like T6061-T6 that are only 40%

https://www.nde-ed.org/GeneralResources/MaterialProperties/ET/Conductivity_Al.pdf

Even BeCu which are used in springs, can be had in 2 major alloys and on of them can be 45% of pure copper (the other one around 25% only)

P.S. There’s thermal and electrical conductivity. I think the original topic here is thermal conductivity (so second link is not applicable).

These go hand in hand though.
Silver is the best both thermal and electrical.
Copper is second, i think aluminium is third. (correct me if i’m wrong).
Benefits of Aluminium is light weight and easy machining, and the fact that you can give it a strong(er) ceramic layer by anodizing.

If i recall correctly, it’s quite similar.
But brass has higher heat capacity (heat sinking properties) than aluminium, it is also heavier.

In most cases both are positively correlated, correct me if i’m wrong. :nerd_face:

Edit: Jerommel was faster

:+1:
Funny as I’ve never thought about this before (edit: probably forgot about it). I have been told in high school that the electrons in metals are the primary carriers of thermal heat for conduction, and the electrons are covalent electrons. And covalent electrons should obviously result in good electrical conductivity.

They never told me that, or maybe i wasn’t paying attention.

Makes sense.
I did know heat through metals behave somewhat similar to electricity.
A good example is a thermostat with a rather thin copper wire to the much larger ‘sensor’, like you find in gas heaters.

Heat/temperature is basically kinetic energy (= energy) of the masses, i.e. protons, neutrons and electrons. The protons and neutrons are stuck in their places, whereas electrons they can go wherever they feel like going. So although electrons have very small mass compared to protons and neutrons, it is their extreme mobility that makes metals good thermal/electrical conductors.

I was talking about electrical conductivity, in that case is applicable.

In any case the amount of theories are astonishing for a 2cm piece of material.

This is a super tiny body in 18350 that because of the titanium electrical resistance should not even output as much power as the
aluminum versions, thus the heat produced by the LEDs will be less, all theoretical.
Not sure exactly as how much the very low electrical conductivity of titanium alloy will impact current as the walls are not that thin to start with so the resistance cannot that high, still.

My guess is that it’s not going to matter that much. So yes in theory, no in practice. There will be an increase in electrical resistance, but this will be so small in absolute resistance term due to quatitative reason (size of the battery tube) that ΔV will remain small/negligible. That’s my guess.

A very interesting post, real life test on the D4Ti 18650 vs D4 Aluminum both NIchia 219C

It is not monumentally worse compared to full aluminum as theorized by some, starts with 8% less theoretical output comparing the 226 number to 209, but as the runtime goes on keeps a higher output for longer than aluminum.
Now that smoother stepdown that keeps the output much higher for longer time could also be due to randomness in the MCU temperature sensor, just a pessimistic speculation, rather than a optimistic one (which would be, copper does that)
That initial lower output can be due to actually more than one reason, optic now matching 100%, higher electrical resistance of the titanium, LED manufacturing tolerance, MOSFET manufacturing tolerance, etc.

Now i’m torn between bare Ti and cyan, might go with Ti so i don’t have to care about scratches and dings they look good on Ti imo.

From my younger days when we use to overclock cpu’s, the heatsinks were most important and a lot of RD was done by heatsink manufactors to achieve the best cooling. They were made using a cooper core to absorb the heat and a aluminum exterior to get rid of the heat. It was always my understanding that cooper absorbed the heat the best but aluminum shed’s the heat quicker, the best properties of both metals.

Hi.

Got my EMISAR D4 Ti from Hank at intl-outdoor.com yesterday.
It is a very nice light, like all the other D4 models.
Mine version is the RAW (A) model:
Nichia 219C 90 CRI 5000k
Optic 10623 floody

  • 18350 tube.

D4 Ti
Weight w/batt : 170.9 g
Weight wo/batt : 126.7 g
Head (alone) : 70.7 g
18650 tube : 46.1 g
18500 tube : N/A
18350 tube : 24.2 g
Tail cap : 9.8 g

D4 Alu
Weight w/batt : 110 g
Weight wo/batt : 66 g
Head (alone) : 30.6 g
18650 tube : 28.5 g
18500 tube : 20.9 g
18350 tube : 14.4 g
Tail cap : 7.1 g

shame its so expensive, u land at around 112$ no matter what emitter more or less unless u want the nichia which doesnt cost extra, the other emitters are +18$ and color choices +15$ just too much…