I ask myself, what´s better for heat transfer....little bit aluminium, or a little bit more brass?!
I have a HS-802, the pill is aluminium and weight = nothing, also very thin.
Now i saw, manafont has a brass pill for HS-801 , i mean, this also fits in a HS-802.
The MF pill weights = 30g.
What´s better for heat transfer (XML) ?
I suspect that contact area is probably more important that the material in this case.
If nothing other than the material changed then you would want copper>aluminium>brass (assuming I remember correctly)
Piers is correct in listing those metals based on their thermal conductivity. The benifit behind the brass pill is it offers more thermal mass. How much of a difference would it really make? Good question. A lot of it would depend on how you use the light ( short bursts or continuously).
Why ?? looks better . i think you're safe either way since that's what the more expensive lights use . brass probably because it's harder so it depend where actually .and most are a combo as well.
Brass is used becasue you can more easily solder to it? however I think the aluminium pill is thermally a better pathway, and a slightly cheaper metal?
I think, the orig, aluminium pill has ~max. 5g.....really better, than 30g brass?
I will use this light longer time continuous.
I have weighted the aluminium pill, it has 7g.
Should i use the 7g aluminium, or the 30g brass pill?
That's hard. It is quite possible that 7g of properly designed aluminium is better than 30g of badly designed brass.
ok, 
i will take a look on it 
maybe i built 2 dropins for my flashlight, one aluminium and other brass, then i will feel the heat.
Build 2 dropins with XML, let them run for 30 minutes on high and then hold them with bare hands for about a minute. After that measure the burn blisters in mm - the one with bigger burns conducts the heat better. Downside: Can only be done with 2 dropins every 2 months. ;-)
depends on how many fingers you got left on your hands.
Unless you're a careless and drunken carpenter working on a bandsaw all day, both hands should give you ten opportunities for this kinda measurement.
I, however, would prefer one of those new slick infrared thermometers. Fingers are important, so I've been told.
ok, after that done, i will test the brightness difference between T6 - U2: T6=left eye, U2 right eye and im looking, on which eye i can see again earlier ;)
but i see, the answer is not easy....i think, both should work and i must find out, which is better for me ;)
Haha, When screwing my first XM-L powed light back together after inserting a battery I made the mistake of doing it will pointing it at my face, of course the switch was on!
It was so bright it made me feel quite nauseous for a couple of hours....idiot!
yes, it's much like looking down the barrel of a gun. Always check if the chamber is unloaded and the safety on - same goes for high-powered flashlights.
Your retina will be happy if it's not bothered by god-knows how many lumens from a close distance.
Any of those would be good perhaps a brass pill would be the least desired. As pointed out eralier the most difference will be seen with the verion which does make the best contact to the flashlight body and transfer heat away with minimal resistance.
The majority of budget flashlights comes with one big flaw. The emitter is sticked poorly to the pill or thermal glued with way too much glue. This is the most critical part as where to start building a decent thermal path. Yo ucan have the best haetsinking in the world but if the emitter is somehow thermally insulated tto the pill nothing would help elsewhere much. The emitter will cook himself sooner or later and heavy output sag woudl be noticed.
I plan to do a test in a few days when my 7 T6 XM-L emitters show up... eventually...