"...Unlike say, an L2P, the can't touch-it temperature is confined to the head. The body of the flashlight and even the lower part of the head stayed under 100°. "
Thanks for sharing your observations , Foy .
I like the idea that the body of the light stays cool .
LOL!!! OK that makes more sense.
I just ordered one in yellow, along with one of their new drop-ins.
I'm$40poorerthanksFoy
200F is hot, VERY hot indeed but I might just say, if it does not burn LED or your hand, is it that bad?
Yes, it may cut the LED life but anyway, folks here are drooling on new emitters every now and then and everybody seems to have at least a pocketful of dropins as spares.
Besides, I tried to melt my 980L driver/led recently running the tops off from multiple batteries.
Definitely far too hot to touch, still no sign of failure...
Probably my next workhorse...
Now you have a portable cooker as well. Might even work as a fire starter for camp fires. 
I cant see how an LED could fail by heat. I had an LED heating up so bad, the cables desoldered and some solder was pressed out between LED and star.. as the cables desoldered, it stopped working. Same LED still works fine. But yeah, life might be shortened really bad, but you said enough about that. ;)
I have melted the solder off the wires on a couple LEDs from heat. The only emitters I ever cooked were due to excessive voltage not heat.
I think we should start a pole and see how many if any have had an emitter heat related failure not a desolder of the power wires an actual cooked emitter.
Everyone seams so concerned with overheating there drop in, but I don't here of many if any heat related failures. It seams like this subject is way over thought and over dramatized.
JohnnyMac and others -
My bad for not spelling out my protocol. (or lack thereof)
When I started the test I simply turned on the light, reached over and picked up my thermometer (not in a particular hurry) and took the initial reading of 96° at 10:48 am. I had been holding/fooling around with the light prior to this and room temperature was probably in the mid 70s. So, however hot it was before I turned it and however hot it got during the few seconds or so it took for me to retrieve the thermometer and aim it at the hottest spot on the host I could find . . . all of that took perhaps few seconds and may account for the 96° starting temperature.
I took all of the readings with no particular schedule in mind. Here they are, starting at 10:48 am, on the morning of April 8, 2012:
10:48 96°
10:50 116°
10:51 132°
10:52 146°
10:53 156°
10:54 170°
10:55 176°
10:57 183°
10:59 196°
11:00 200°
It was very unscientific. I took each reading, using the hottest temerature I could find on the light. I appologize if using "10:48" suggest it took over 10 minutes to reach 96°. That is merely how hot it was after me holding it, turning it on and off a few times, etc.
About the drop-in I used.
I've been inclined in the past to defend my $40 Extech MN36 DMM. While I make no claims for its accuracy, E1320 has sent me several lights, telling me beforehand how many amps they pulled on his Fluke. I then test the same light, using the same brand/type battery and other times using another battery and without exception, my reading is within .10 or so of what he got.
Most of my UF XM-Ls from Manafont pull between 3.5 and 3.75 amps on high with a protected Solarforce 18650/2400 using an L2 or L2P. I have this one drop-in however, that has always pulled more than any I've ever received and I chose that one specifically for this "test" for obvious reasons. Other than curling the black donut cover into another shape, the drop-in seems no worse for the wear. It still pulls 4 amps and it still blows the doors off every other drop-in I have.
There has been some speculation about using a high power module in this partially plastic host. This "test" merely proves that a P1 will not go liquid, even at stupid high levels of current. It also shows that (one of) the design goal of isolating heat away from the user's hand may have been met.
I didn't mean to mislead and I don't make any claims other than what I have demonstrated. I simply turned the light on and 12 minutes later it was 200°. I appologize for not describing my actions more accurately.
justageorgiaboyalongwayfromhomeFoy
Good idea. Heat definately is a topic because lumens sag, but getting some data about fried emitters would be nice.
I suggest "killed by heat", "killed by voltage/amps", "desoldered by heat and disposed" and "none" or sth. like that as options. Maybe someone even had an LED that just stopped working because it got so old?
But much more scientific than what I would have done. You know we all truly appreciate the effort.
Only heat failure I've ever seen was on POP-Lite headlamp.
Q5 dropped the contact with cooling base, bare emitter chip, no star or aluminum plate...
With cooling: none.
edit:
Again, insulating heat away from users hand is not that bad idea on the basis of "first man, then machine etc...".
I have quite thin skin for no particular reason in my hands, sometimes heat just is too much to bear.
Take home message:
Yes, the heat builds up in the head, which could potentially shorten the dropin’s life.
However:
a) Your hand won’t get burned
b) You will never come close to approaching the MTBF lifespan of the LED anyway, so why worry?
You can now run high current dropins in a cheap host without worrying about getting burned from touching the body of the host. And for me, that is a win.
wellthattheredoxplaneuhlotufthingsrightthurr 
LOL, we love you foy!
I unnerstood the first post completely.
Sorry, I haven't been posting much and I'm going thru withdrawal
It’s easy to get burned out welcome back we missed you.
The data sheet for the XM-L (link to pdf file) specifies a maximum junction temperature of 150 °C. 200 °F (about 93.3 °C) is still well within it’s limits, although I can’t find any information about how much high temperatures for extended periods of time might effect it.
I guess the question is, how hot was the LED itself getting?
Thanks, Foy !
Been looking at this one since it was released.
Have been very hesitant because it wasn’t aluminum.
I have a G2 and the stock bezel gets way too hot for me to be
comfortable with, even with a R2.
This puts my mind at ease, and now intend to get one. 
foycausedmetobuyanotherlight. :bigsmile: