UF-T90 - Dedomed MT-G2 Mod (Pic heavy)

Finally, I have a light that is starting to approach my holy grail for an outdoor flashlight. A light that can light up far down field and that also gives nice near-field illumination. But not so much near field that I can’t see well down field or that makes me squint and totally loose my remaining night vision. A light with decent cell capacity and heat sinking.

The great news is that anyone with beginning mod skills can replicate this light for about $90 and a fraction of the time and effort I put into this build. The recipe is:

· UF-T90 from Wallbuys ($70 after discount code)

· MT-G2 on Noctigon

· R10 Resistor

· Better springs (or just copper spacer in my case)

The light already has a great driver for the MT-G2 (HX-1175b) and also an Omten switch.

The beam pattern on this light is so like a good thrower, but on a bigger scale and with incredible spill. Most useful spill I have ever seen. I'm getting such a thrill seeing stuff that I don't see with all my other lights. I have serious throwers and flooders. Both leave me wanting some of the other. I have 3, 4, 5, 6, 7, and 9 emitters lights. They are the most useful, but they just put too much light in the near field. I want to see far and outside of the spill of light.

Right now I'm running this light at high current to see how it behaves. I will probably shoot for a 9 amp high mode with a time out turbo mode. Nine amps is the last sweet spot on the MT-G2 curve.

Summary of mod:

  • Dedomed MT-G2 - No MCPCB in order to get emitter higher in reflector
  • Stock Driver with 07N03 FET swapped in.
  • A R10 resistors added.
  • 9 amps measured to the emitter before light was assembled. Something isn't adding up here. I think I must have had a poor connection on the emitter current measurement.
  • 171kcd throw with .035" shim 198kcd with .56" in shims and at 11.3 amps. Still working on focus. MT-G2 throw measurement thread here.
  • On high, you can feel the heat coming out almost instantly. The light gets very hot within minutes with 2 R10 resistors at 11.3 amps.

Some pics:

Light has 2 lenses stock. Took one out and will not used emitter base. So had to build up integrated pill with 3 .07" disks and one .035" disk spanning the wider area. Mouse over is holes in integrated pill being stuffed with copper.

These are the leads to the emitter. They are 10 or 12 gauge copper wire wrapped in a layer of kapton tape. They are a slightly snug fit through the head so that they also conduct heat. Very hard to solder to after pressed into head.

Poor emitter has been through hell a few times. Had a couple accidents machining copper with the emitter in place. Also, grounded off the corners to clear reflector hole. Not symetrical at all. Luckily, MT-G2's are tough. My MT-G2 dedomes never look good as I just pick off as much silicone as I dare. What it looses in attractiveness, it makes up for in performance. Emitter was too high into reflector in the below pic. Had to add another .056" in copper disks (with hole for emitter) to lower emitter in reflector. Bottom of the reflector presses against the surrounding copper. So it helps move the heat too.

Copper round bar that was eventually pressed into built up head. Mouse over is bottom of bar pounded out and flattened for next copper disk. I kind of got sloppy trying different utensils to pound with. Hence, all the damage in the surrounding copper disk.

Very hollow head. Lined with copper sheet and insert copper and aluminum disks.

Bored center and pressed in 3/8" copper round bar. Below pic is second liner getting fabbed. First liner spans entire length of head. Thickness under emitter is almost 1.25". The liners seem to help transport the heat across the long head nicely. They are sized to very tightly press fit. Mouse over is how I determine size of copper liner. Use cardboard mock up.

Ran a 5 minute test on a HX-1175B driving MT-G2 with 3 KK ICR's. The N-Channel FET was replaced by a 70N02's and 2 R100 resistors added to the existing stock R062's. I changed to the lower resistance FET's because Relic had reported heat issues with his T90. The HX-1175b driver is from a UF-T90 (The long light with SST-90 from Wallbuys). I think it is also used in the Lustfire 3U2-X3. The cells were down a little (4.12 volts resting) from several short runs last night. The emitter was getting 10.7 amps (down from 11.3 last night). I don't know if the current was down to changing the set up or from lower cells.

The driver was loose and not heat sinked. At the end of 5 minutes, it was at 203 degrees F (95 C). The heat appears to be generated mostly by the FET's Source Pin resistor bank. The FET didn't feel hot. The MT-G2 lux remained unchanged through the test. Temperature of the head was 170 F (77 C) at the end of the test. The head is heavily heat sink modded. Current was down into the 9's at the end of the test, but I don't remember the first decimal.

I think this indicates the driver might be able to handle driving an MT-G2 around 11 amps (Maybe more?) with 3S cells, but I the driver should be well connected to the heat sink. I ordered a few of these drivers from 2 different ebay vendors. Hopefully, they send me the real deal and not the HX-1175c RaceR86 received. Here are what I ordered (Not yet received). The second buyer I have no experience with either. The specs in his ad are low, but the picture is of the HX-1175b.



Here is the driver potted with my potting recipe. Mouse over shows driver retaining ring I made from 10 or 12 gauge copper wire (pressed in tight). That spring had to be replaced by copper slug.

Tail spring fried instantly. Switch was going to next. So I turned light into a twisty. Mouse over shows Kapton tape that was needed for power to disconnect. This is temporary. Switch is back in. It is an Omten and seems to be fine. Just removed the spring and soldered the brass plunger directly to the switch. I used the tail cap to control pressure on cells.

The light illuminates a big area nicely. Good general purpose light for big and deep areas. Atmospheric conditions are bad tonight. It's been raining and the humidity is high. So much of the beam gets absorbed by the moisture in the air. Since I have not pictures posted in those same conditions I took a comparable using a DST with a domed XM-L2 T6 3C driven at 6.5 amps (Mouse over). The MT-G2 has the type of beam I want 99% of the time.

On a clearer night. Unfortunately, it looks like the beam hit the right side of the tree and sky.

Here are 2 driveway shots (one is mouse over). The below pictures were took on the first night with all the moisture in the air.

Another part of the drive way. I measured once. I think the utility pole is somewhere between 500 to 600 feet (200 yards) away. Mouse over is just another shot (not driveway). Don't know how far away the transformer is.

To Do's:

  • Need to piggy back an different MCU on the driver.
  • Add side momentary switch.
  • Consider removing phosphor layer around (not over) the grid of crystals to get rid of yellow around corona. Not sure I want to do this as I think this improves tint and cri down field.

Lessons learned:

  • Didn't need to do all the machining to get wires under the emitter. The T90 reflector is designed for emitter to be below bottom of reflector. Currently, the bottom of my dedomed MT-G2 is . 056" below the bottom of the reflector. I need to try .042".
  • Can't think of anything else at the moment. This is my favorite light now. Happy, happy, happy.

Now this as an MT-G2 build I like!

Constant current, and great throw too.

Nice mouse-overs. :)

Larger spring + copper braid + large omten switch should have no problems with 12A as far as my experience goes.

You will be modding the driver into using momentary switch?

I like your creativity with the emitter mount. Good job! :stuck_out_tongue:

That looks great man!

It seems like more of us are getting into copper mods and adding as much copper as we can into our lights. I like to see how other people do it. Where did you get your rounds? I just places another order with bopper @ ETSY last night for the copper for 4 or 5 different projects I’ve got coming up.

Emitter/driver swaps are one thing but your not really building a light till you’re shoving copper pipe down a host’s throat.

Again nice build, can’t wait for those beam shots.

Nice effort. You need a Tofty switch in there. I'm not sure if it would go straight in but it is a standard size switch. If I modded an led like that there would be two chances of it never working again.

Great work, that should really be a beast of a light. That is a lot of lumens in a nice tint reaching way out there. Very Cool!!

ImA4Wheelr is really honing his skills with this one. Maybe the next frontier will be to dramatically increase the exterior surface area of the host to exchange all that heat with the air. Not just an add-on copper spacer/slug with 1/4” slots cut in for “fins”. Things that make you go, “hmmmm”. Hell, the flashlight is already long anyway. Whats another 4 inches of functional good looks added between the reflector and pill?

Maybe use the end of one of these for the floor plate and a direct thermal path. Bore a hole through the center and press in a copper rod to transfer heat through the entire sink (these longer round AL sinks are said to not do a good job of radiating heat through the entire length of the sink, and I believe the copper rod will solve that problem). If you cant cut threads and bore, then hacksaw and JB weld from the inside. :bigsmile: Just thought Id throw that in there to get the gears turning… and you’ve got the skills to make it work. :wink:


Thanks to OL’s referral, Ive been getting my copper disks from SupplyDiva on etsy, but the wait is often 6-10 weeks, arriving from Mexico. Quality is often a mixed bag of mediocre pitted semi-rough stampings, and the typical disk still requires a good amount of shaping and sanding to perfectly flatten and level it. How long till you receive your orders from Bopper after ordering? Can you please comment on the quality and precision of the disk? Are they made in Mexico?

Sorry to derail your thread ImA4Wheelr. Much respect for your innovations with this one, Sir! Thoughts? :slight_smile:

170kcd with mtg in a reflector. Wow! Is that emitter damaged A bit? It looks like some of the phosphor Is ripped of.

It looks more like solder on the dome, it is by far the most beaten up domed MT-G2 I have seen .

Very nice mod, I especially like the way the led is mounted. I hope the plans on the driver and switch will work out fine.

Yikes. That’s a lot of copper. I like it. You should feel the heat moving the outside of the head almost instantaneously.

Nice build. Look forward to the beamshots :slight_smile:

I’m not sure where they come from, I’ll ask her now and report back, shipping is from Cali and they were delivered 3 days after ordering. Quality is very good, they have a very good surface finish and clean edges, no pitting at all and tho I did sand the top where the emitter goes I didn’t sand between each one (I solder multiple disks into a slug).

Also about bopper- if you need multiple sizes of disks (different diameters or gauges) just send her a message first and she’ll create you a custom listing for exactly the number of pieces you need.

edit bopper has responded, they punch all their stuff themselves in house except for their sterling silver.

Thanks guys.


Thanks for the switch tip. Yes, I want to go no tail switch (twisty) and momentary side switch. But after the scratch build is completed.


Thank you man. Nice tip on heat sinking. Have you seen the size of my scratch build fins yet?


Thank you. I get almost all my copper from copper pipe that I split and flatten. I got some great 1 5/8" pipe that is .07" thick from a local guy on Craigs list. It folds out to around 5 inches wide. I got a bunch of 5/8" OD tubing that is .035" thick from clearance at Home Depot. I got so .021" thick sheet from a kind member here on BLF. Monitory your local Craig's list.


Thank you. If I were to keep this light a tail switch, I probably would go with Tofty's switch.


Thank you. Yeah, I'm a big fan the tint on the MT-G2's we all use.


Now up to 198kcd. Shimmed an additional .021". Still working on focus. Yes, some of the phosphor got gouged off in an accident. I reflowed the emitter to the head to early in the process and then tried to do machine work around it in the head. Acctually had several impact accidents. Luckly none of the phosphor over the crystals was hurt. So I have a nice warm tint with no purple.


Thank you. Really appreciate all your crash testing work. Without that, I probably would not have build lights like this. You the man.


Less copper than it appears. I mostly line and strategically place disks. Oh, and use copper bar under the emitter whenever I can. Yes, you can feel the heat almost as fast as you turn on the switch on this light.


Thank you.

EDIT: Addition made. Just realized I missed 18650's post.

I hope to finish the thread and get beam shots tonight.

Added beam shots to end of OP. Got some rain today. So atmospheric conditions are lousy for beam shots, but they will give some idea of the beam pattern.

Light gets hot fast. It was 122 F after a few minutes. I would like to turn it on take temp and time measurements. At what exterior temp should I turn off the light off?

Whoaaa that is some great work! Those beam shots look amazing!

Thank you Chazzy. Much appreciated. May I ask what is your avatar?

It’s just a picture I found online of some tritium tubes.

They look like the keychains I make out of 1/4” acrylic rod with 1-2mmø trit vials in them.

Beam shots look amazing. If you want a pretty accurate way to measure distances (and have an iOS device) download the free app “Measure my land”. (Maybe on android too)

Beam looks great!

Good guess Cereal. Thanks Cereal and RaceR.