I’m not talking about a little bit, more like several ounces. It does much more than add a tiny bit of thermal mass. 
Mass isn't a magic bullet that makes heat evaporate or teleport into a parallel universe.
Tell that to the Elephant taking a 300gr .454 Casull in the brain.
Edit: A rogue Elephant that had been rampaging villages and killing men, women and children happened into a village where there was a hunting guide. Not having his rifle handy, he shot it with this very powerful handgun. Dropped it in it’s tracks, effectively dissipating it’s heat with a little bit of mass. The villagers treated him like he was a god.
That said, if mass isn’t so critical, why is it always at the top of the list in the most powerful lights? It might not be magic, but you don’t get far without it.
Apples and oranges. Let’s keep this friendly!
If a pill is thin under the mcpcb and having a hard time transferring heat to the rest of the pill, then maybe adding copper under the mcpcb would help.
Adding excess mass does nothing to solve the thermal problem if it’s not getting the heat out to where it can be radiated to the air. Surface area is really what would help in this case, but then you lose the benefit of the small light. (same goes with adding unnecessary weight)
I think that's true for continuous run times, say >10 min., but many people use a turbo mode for 30sec to a minute, then have a light off or on low. Then a massive pill is a thermal analogue to a capacitor in an electrical circuit, quickly accepting the heat from the led on high to be dissipated more slowly when off or on low.
The differences between playing with a light and working with a light I suppose.
When a storm knocks down a large tree that has to be cleared from the road, or a fenceline, and it takes an easy hour to do, you don’t want your emitter sliding off it’s star. When your $600 pedigreed pup gets under the fence and is lost in the back 40, you don’t want to keep shutting the light down so it can cool while you look for the poor guy.
But I hear ya. Always a compromise, as with so many other things…
I thought this thread was about a fun pocket light, more than a heavy duty work light.
So... should I shoot an elephant to keep the light cool, or shoot the light itself? I can see how needing to find an elephant to shoot every time you want to use the light could be a little inconvenient. Shooting the light would definitely reduce its heat output dramatically, but I think it might have a detrimental effect on the runtime. I will need to do some further research on this, but thanks for the tip, definitely sounds promising!
No, train the elephant to hold the flashlight in it's trunk, the elephant is the heatsink.
And then you shoot the elephant? I'm very confused.
The question was one of mass not being the magic “bullet” which made my feeble mind remember a story about 300 grains of copper mass indeed being the magic bullet. So, relevency being the key without getting further off on this tangent, mass is of course crucial to keeping heat off the emitter. Be it added copper or thick aluminum construction to begin with. The light in question was not designed for the wattage that is being put in it, so I suggested added crucial mass in the most effect composition commonly available…copper.
Go ahead, put an MT-G2 in a Xeno E03, whatever. Just because you can, doesn’t mean you should.
Shoot the shi*, feed the elephant, build the light.
There's no need to be condescending about it. A turbo mode is fine for most folks. It's certainly fine when I hike at night for a few hours. I have other lights that can run at higher levels until the batteries go dead, but they're much heavier. There's a lot of appeal in a pocketable light that can put out stupendous amounts of lights, even if for short periods of time. Anyone that likes the SRK should appreciate that, although I wouldn't call that light pocketable.
Would you be able to show me a picture of the emitter sitting in the reflector. Some quick measurements and calculations (based on your pictures) show that the flat bottom portion of the reflector is not large enough to allow boring out for the MT-G2 emitter base. The base is 8.9 by 8.9 mm (whereas the XM-L2 is 5 by 5 mm), and i would think you would want the reflector starting below the actual emitting area vs above it. How did you facilitate this?
You would think that based on the results with XML & XPG, but the MTG2 is different. Best focus is usually with the LED farther back than with the others. Usually if the base of the reflector is .030" thick, you want the bottom of the reflector about level with the top of the square substrate/package of the MTG2. Enlarging the hole so it can poke up inside makes the beam worse.
Hi! I don't have access to the light right now but will in a couple of days. If I remember correctly I did end up opening it up just to or maybe a little bit past the flat portion, although I realized that I don't have a picture of the finished reflector. It isn't perfect but it works great, I did it with the dremel bits I had on hand which weren't ideal. I will try and get back to you when I get back, but what comfychair said is right. I didn't think too much about that when I started out, I just made it big enough for the emitter to drop in then tried it out. Figured that I could always take more off or mess with it if it didn't work but it works fine as is so I didn't touch it again.
Interesting mod. Will be giving this one a try next week!
[quote=RMM]
Hey RMM, how did the MT-G2 build come out using the ZY-T08? Did you ever get er done?
Curious, would like to try one myself.
nice mod ! 
i like this formfactor size, especially in your modded version with matching a SRK.
How did you get those two the solder blobs to stick to the aluminum pill?
The MT-G2 came out well with the ZY-T08. I used one of the original DRY drivers, copper braided everything, etc. IIRC it does around 5.5A on turbo w/ Pana PDs and 6.5A w/ 20Rs. I still hate the whine from the driver, it is just too much for me. I tried changing out switches, tightening and cleaning ground, etc. but it is still pretty bad.
I'm going to switch the DRY out for a zener modded 105C with an FET which I now feel is a superior solution. In my testing it will pull over 10A on 20Rs and still gives me good mode selection and very minimal whine. DBCStm put one in his MT-G2 M8 and had it putting out over 4000 lumens on 20Rs and measured a 7 lumen moonlight. Doesn't get any better than that! If you want to turn it down a bit just run a lower mode or run weaker cells.