# QTC flashlight - from scratch (non battery-crush)



## TheFraz (Apr 20, 2012)

*QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 video*

Hello all,

Long time lurker here. Decided to post this as I am very pleased with the way it has turned out.

I wanted to design a very durable, very simple light. I've always liked the simplicity of QTC and have always been driven away from drivers and PCBs in LEDs, so I decided to try and build a light based around QTC.

Here is what I came up with:







Took a lot of trial-and-error and several failed attempts, but now it ramps smoothly and seems to be extremely efficient. Abrasion wear was a problem at first, and I also wanted to do away with battery-crush design. After several prototypes, it finally functions as I imagined it with no wear. Also attached are a couple videos of it in action:





Anyway, thought you might enjoy and good to finally post!

(7/2/2012) Update:

Here is a video of the version 2.0 QTC engine. The single full turn makes ramping brightness so much easier, and now I've gone through a couple thousand turns on the old engine and figured out the wear points and feel good about fixing them. The lines on the prototype show where a full rotation achieves full brightness. 



(9/3/2012) update: Drop test from 25 feet.



(9/14/2012)update: Finished the v3 engine and body design. below is a pic beside the v1 design and video of it against a tk41







5/4/2013 Here are a couple pics of the prototype progression. From left to right is the oldest prototype to the newest.


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## jabe1 (Apr 21, 2012)

That looks great! How about a few more details?
How is the QTC protected? What battery is it using? Which emitter?


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## TheFraz (Apr 21, 2012)

jabe1 said:


> That looks great! How about a few more details?
> How is the QTC protected? What battery is it using? Which emitter?



Thanks ! I'll take some pictures of the engine and the light disassembled when I get a chance. It is driven by sort of a series of pistons. I wanted to be as minimal as I could with the design. I try to stay away from threading/screws/glue etc as much as I can - it's only threaded in one place. I wanted it to be simple to assemble/disassemble. Uses an XM-L and a 26650 battery.


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## Mattaus (Apr 21, 2012)

TheFraz said:


> I wanted to be as minimal as I could with the design. I try to stay away from threading/screws/glue etc as much as I can - it's only threaded in one place. I wanted it to be simple to assemble/disassemble. Uses an XM-L and a 26650 battery.



Sounds like the perfect light to me! What are the dimensions? What material is it made from? Being QTC I imagine it is a twisty and has variable brightness?

I'm watching this thread intently now


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## Harry999 (Apr 21, 2012)

Now that is really interesting. I am a big fan of Peak lights which use QTC material so I look forward to seeing how this develops. I assume this could be built for any battery size...


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## TheFraz (Apr 21, 2012)

The light is 4.85" x 1.6". I meant to overbuild it, but it may have overdone it a little. The walls are very thick, around .25" on the battery tube, and it's pretty heavy - although I like heavy . Yes, it can be done with any battery type (as long as the LED doesn't get too much voltage from the particular battery setup), and it is a twisty with variable brightness. Works very similar to a wall dimmer in a home. I'm working on a couple more designs/builds now with different reflectors and battery combos. There's just a couple more small bugs I want to iron out to help with the feel and get the most out of the setup.

Here is a pic of the prototype beside a TK41. Both are on high (TK41 is on turbo), 6ish inches from the wall.


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## ^Gurthang (Apr 21, 2012)

Can't wait to see & read more about your work. I've been interested in QTC since I first read about it here, your 2nd video is short but I see how well the light ramps. Keep all of us informed.


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## jabe1 (Apr 21, 2012)

What is the finish on the light? It looks great!

If you're not careful here, this could become a side business for you.


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## Tofty (Apr 21, 2012)

Also looking forward to seeing how this torch works in relation to the qtc control.


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## TheFraz (Apr 21, 2012)

I'm out of town, so I can't put up visuals atm, but to answer your questions from earlier: It is made of 6061 aluminum and finished with Gun Kote. I like the way the matte finish on the Gun Kote looks (it was also the only aluminium finisher I had laying around). And I am trying to make this light look and feel kinda like a gun engineering wise - well built (even overbuilt) and easy to break down and clean if necessary. However, I am looking into more durable solutions for the finish as well.

As far as the way the qtc brightens and dims this prototype, it works very smoothly with no flickering or artifacts. A good example if you have a QTC pill - make a circuit with wires running to and away from an LED. Put the pill on the + end of a battery and the - wire on the negative end of the battery. Press the + wire into the QTC directly, it gives you an idea of what the material is capable of. Ramps like butter when you don't have to worry about movement of the pill or shearing force. I'll try to make a little better video showing the operation if I can get a little time tonight.

When I get back home, I'm going to make a couple small adjustments to the build, mostly involving tactile feedback from the twist (also a better reflector/optic and warmer LED). Looking forward to tweaking it a bit more!

Thanks for the interest guys!


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## Harry999 (Apr 21, 2012)

Looking forward to seeing future developments especially if you eventually consider making these available for interested CPF members. Hint Hint!

Sent from my smart phone using Tapatalk


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## Harry999 (Apr 21, 2012)

Double Post - I need to stop using my phone to post here!


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## borrower (Apr 22, 2012)

+1 to seeing the guts of this... one of my many not-done projects is to QTC a flashlight. There's some of my failure/success with qtc here: http://forums.mtbr.com/lights-diy-do-yourself/qtc-infinite-variability-730630.html
(you might have to register to see pictures in that thread, but they don't spam you)


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## TheFraz (Apr 23, 2012)

Finished work on a new engine today - a big upgrade over the first one. The brightness level change is much more smooth. Action also feels better. You can turn it up to full with one hand now. Also reduced the number of solder points to 2 and took it down to a total of 2 screws (I hate extra parts). I think I can also shorten the light a little more on my next upgrade.

Here's a more detailed video of the operation of the light:



Now to work on the AA version...


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## Mattaus (Apr 23, 2012)

TheFraz said:


> Now to work on the AA version...



NiMh AA's or 14500's? I'm very keen for an extremely compact AA twisty mule. No driver, no optics/reflector and no switch. It could be so short. Make it happen and I will buy at least one!


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## Coup de Grace (Apr 24, 2012)

I'm keeping an eye on this thread. I have a QTC Peak in my pocket right now. I'm hoping the QTC holds up.


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## Harry999 (Apr 24, 2012)

Mattaus said:


> NiMh AA's or 14500's? I'm very keen for an extremely compact AA twisty mule. No driver, no optics/reflector and no switch. It could be so short. Make it happen and I will buy at least one!



+1

Sent from my smart phone using Tapatalk


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## TheFraz (Apr 24, 2012)

Mattaus said:


> NiMh AA's or 14500's? I'm very keen for an extremely compact AA twisty mule. No driver, no optics/reflector and no switch. It could be so short. Make it happen and I will buy at least one!



NiMh or alkalines for the current model (I like the idea of having one that uses standard batteries). The QTC doesn't stop the voltage, so I have to keep it in the right range or *poof.* I think I can get the total length of the unit with 3 x AA to approx. 7" with an optic in place. Without an optic, under 7" shouldn't be a problem. The 26650 model above I think I can get to 4.25" or so comfortably. I think I could make a super short 1 x 14500 unit - I'll look at that too. Once I get them running perfectly, I'd be more than happy to make a production run. These things are gonna be like tanks and shouldn't have anything that makes a failure bottleneck.

Gonna now start twisting (not the dance) to figure out if there are any wear points..


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## Harry999 (Apr 24, 2012)

That is excellent news. I think we will all be keeping an eye on this thread looking for your updates as you progress towards a production model.

Regards

Harry


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## TheFraz (Apr 27, 2012)

Had a chance to work on the machines a bit today and finished up a CR123 version of the bigger light shown above. Here are a couple pics of the light on super low and on high using one primary 123.










I haven't dressed it up yet or finished it, but new changes to the engine have worked great and it functions better than previous versions. I think I'll have the feel of the light set pretty soon.

Thanks for all the interest guys.

-Fraz


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## Harry999 (Apr 27, 2012)

Seriously it looks great as it currently is as a prototype!

Sent from my GT-I5800 using Tapatalk 2


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## Mattaus (Apr 27, 2012)

Harry999 said:


> Seriously it looks great as it currently is as a prototype!



+1. Obviously a bit hard to see from photos but it does look good.


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## TheFraz (Apr 28, 2012)

^ Thanks guys!  Here is a pic of the somewhat finished 123 light next to the bigger one with Mack looking on...


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## Mattaus (Apr 29, 2012)

I like how you've incorporate a sort of brightness level indicator into the rear half of the lights (if those increasingly large notches are what I think they are). 

Is there a matching notch on the front end? These look HA anodized as well...you must have access to a serious work shop!


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## TheFraz (Apr 29, 2012)

Mattaus said:


> I like how you've incorporate a sort of brightness level indicator into the rear half of the lights (if those increasingly large notches are what I think they are).
> 
> Is there a matching notch on the front end? These look HA anodized as well...you must have access to a serious work shop!



Good observation - yes, those notches are a sort of indicator of the operation of the light. No matching notch yet...still in the tweaking stage... 

I wish I had access to a serious shop! This is garage mechanics....benchtop lathe and mill with some GunKote. And a little baking for curing in the house oven when I can get away with it...:devil:


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## Mattaus (Apr 29, 2012)

TheFraz said:


> is garage mechanics....benchtop lathe and mill with some GunKote. And a little baking for curing in the house oven when I can get away with it...:devil:



Well impressive stuff regardless. I've just started learning how to use a lathe and my appreciation for what some members here can create went up infinitely after my first session. 

And yes I've been banned from using the house oven for any non-food related baking :-(


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## TheFraz (Apr 29, 2012)

Thank you...I'm self taught myself. Best way to figure it all out imo is to crank it on and start having success/making mistakes. Well, that and Google.. Threading was especially intimidating at first...only took a few ruined scraps to get it going! One of these days I'm probably gonna be forced into some sort of outdoor oven...


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## Mattaus (Apr 29, 2012)

Well even though I can make basic parts on the lathe now I still tend to pay people for custom work. Your QTC lights look great and if you ever decide to make and sell a AA based light I'll be all over it - I have 10 brand new Eneloops and no light to use them in (mistake on my part) and the driver less, switchless design of these lights would be perfect...although I prefer single AA and 1.2V won't do much :-/


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## TheFraz (Apr 29, 2012)

As soon as I get these thing functioning exactly the way I envision, I'll be more than happy to do a production run for those interested. I just want to make something that people will enjoy/appreciate/ find useful. I should have several battery configurations available. Hopefully I can get one working like you are looking for - I'm waiting on new parts to come in now for a beta prototype..


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## Mattaus (Apr 29, 2012)

TheFraz said:


> As soon as I get these thing functioning exactly the way I envision, I'll be more than happy to do a production run for those interested. I just want to make something that people will enjoy/appreciate/ find useful. I should have several battery configurations available. Hopefully I can get one working like you are looking for - I'm waiting on new parts to come in now for a beta prototype..



Sounds excellent. Less parts to break in these sorts of lights which makes them very good for camping/hiking etc.


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## Harry999 (Apr 29, 2012)

That is exactly why I am interested as well. This looks like a potentially great emergency light. I love simple twisty lights especially those with a progressive UI. With less moving parts I feel more confident in the light. 

With a smooth ramping QTC based control it will be a nice EDC as well...

I admire you skills. I could not do any of that. My limit is filing out the holes on a Ti clip to fit it on my Jetbeam E3S.

Sent from my GT-I5800 using Tapatalk 2


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## ^Gurthang (Apr 29, 2012)

Really impressive work Fraz, very well finished. I'm curious where you're sourcing the QTC and waiting to see more of you work.


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## PhotonFanatic (May 2, 2012)

TheFraz said:


> . . .
> 
> As far as the way the qtc brightens and dims this prototype, it works very smoothly with no flickering or artifacts. A good example if you have a QTC pill - make a circuit with wires running to and away from an LED. Put the pill on the + end of a battery and the - wire on the negative end of the battery. Press the + wire into the QTC directly, it gives you an idea of what the material is capable of. Ramps like butter when you don't have to worry about movement of the pill or shearing force. I'll try to make a little better video showing the operation if I can get a little time tonight.
> 
> . . .



Care to elaborate a bit on the interface you are using between the QTC and the positive and negative leads? How are you avoiding abrasion as you mentioned--is the contact from the +ve end of the battery a piston, i.e., no twisting, just pressure to the QTC?


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## TheFraz (May 9, 2012)

Thanks for the compliments! Sorry it's taken me a bit to respond - been pretty busy lately. To answer your questions, I got the QTC a while back from an online vendor (that I cannot remember the name of lol...although it says "Rapid" on the plastic bag they came in, if that helps). Yes, I'm going for very few moving parts and as little soldering as possible. I want it to be very durable. As for the QTC interface, it has taken a lot of R&D to get it right. All the parts for the user interface/engine have been fabricated. It seems most solutions that look good on paper don't look or feel so good in operation. I'm still working out final bugs on my engine design now (have given it several thousand twists to try for any failures that might happen) and hopefully I can tweak it to the point I feel it very unlikely to have any abnormalities when reproduced (can't go into too much detail yet, but I'll take some pictures of the final engine). The main trick I wanted was to have constant contact with positive and negative springs to the battery so it wouldn't rattle when the light is in the 'off' position.

And since I like pictures, here's the QTC123 next to a LD10 for a size reference:






Now I'm waiting on my parts/aluminum to arrive for my final couple models. I also wanna add some warmer LEDs...I just really like the warmer colors that have come out recently.


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## Mattaus (May 9, 2012)

Use Nichia 219s for your LED. I love those emitters. Any consideration for other metals like copper or even titanium? Sorry if this has been covered....I'm on my phone and searching is a pain.

Also count me in if you produce the CR123 versions.


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## TheFraz (May 9, 2012)

Yeah, I'd definitely like to try the new Nichias out...I haven't seen one being used yet but I've heard nothing but good things. And yes, I'd definitely consider other metals. It shouldn't be too hard to incorporate them once I finalize the design.


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## Lumenz (May 22, 2012)

Any updates on the progress? I will be monitoring this thread. I have been getting the Peak QTC lights but they are not exactly what I was hoping for. I like the smoothness of operation of your flashlight.


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## TheFraz (Jun 12, 2012)

Lumenz said:


> Any updates on the progress? I will be monitoring this thread. I have been getting the Peak QTC lights but they are not exactly what I was hoping for. I like the smoothness of operation of your flashlight.



Thanks for the interest! Sorry it took a while to respond. Finally got my materials in. Got a chance to get on the lathe tonight and finished the optic holder/heat sink for the next prototype.






On paper the bug fixes look good...we shall see. I've been using the other 2 prototypes like crazy and they are holding up great. Hopefully I can put some pics up later for this model 2.0 light. It should be better in every way than the 1st one.


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## Harry999 (Jun 12, 2012)

Look forward to the pics.


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## persco (Jun 13, 2012)

Wow. What a great thread. Impressive work, Fraz. I'll keep a close eye on your progress.


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## wolfy (Jun 13, 2012)




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## gunga (Jun 13, 2012)

Very cool. I am following this cool thread.


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## Phototropin (Jun 13, 2012)

Love your work, it's coming along very well. 

Does the light flicker at all? I have used QTC at work to make basic pressure sensors, and found that when I apply intermediate pressure I cannot get a stable resistance/conductivity measurement (keeps fluctuating and won't "settle"), so I'm limited to using it basically as an on/off switch instead instead of a variable resistor.

I did a quick google search for "Rapid QTC", and by the results (if it is indeed the same product) it appears to be a similar product to mine (silver nanoparticles in silicone I think). Does your QTC just look like a thin (~1mm) browny grey rubber? 

Awesome looking light BTW, I hope you keep the final design as simple as that. (But maybe in Ti, Cu or brass... :devil


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## TheFraz (Jun 13, 2012)

Thanks guys. As far as flickering, that was one of the biggest problems to overcome because the QTC reacts to such small changes in pressure. And if there is any binding it readjusts eventually as you are describing and loses stability. It has to be implemented just right to get it to work reliably and in a way that is pleasing to the eye. Lots of ideas seem good...until they are built lol. It's taken me about 13 prototypes to get a couple that work like I had imagined they should. Yes, the raw QTC looks like a tiny wafer of rubber. I plan to keep it simple looking in final stages...well, because I love minimalism . It's just so hard to make something simple with a clean look and design that works, it's frustrating. Below is a video of the smaller of the prototype doing some small incremental brightness shifting to try and show the stability of the engine. The only thing that limits how smooth the light ramps is how smooth your hand can turn it (and as my hands are pretty big I struggle to get fine movements on this tiny light). But to reinforce the idea, I have left it on at around 50% brightness all night, then in the morning slowly ramped it down to see if there is a 'rebound.' There is not - it works great.



-Fraz


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## Phototropin (Jun 14, 2012)

That's fantastic Fraz, very smooth. I have noticed in my tests that it takes a little while to "break in" the rubber, so will be interesting to see if your max and min output notches (if you were to mark the outside of the flashlight with those intensity bars referred to earlier) change over time as the rubber is put through repeat compression and decompression cycles.

I'll be keeping an eye on this thread, very cool TheFraz, very cool.


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## TheFraz (Jun 17, 2012)

Finally finished the latest model. This one is quite a bit smaller at 4.5". It also is lighter, brighter, and uses a warmer LED. But the thing I like about it most is that it now requires a full turn to go from full off to full on. Much much better feel. Here are some pics - I'll try to post a video tonight after I grab something to eat (starving lol). The bottom one shows the size difference from the old model. Also, this new light will look different when I 'finish' it...still have a bit of cutting to do on the body before I coat it.











-Fraz


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## gunga (Jun 18, 2012)

Very cool! I think I want 1!


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## XFlash (Jun 18, 2012)

Been enjoying this thread, love to watch a custom light in its progress.
I love this design, I want one also.
A low low is important to me, and this light seems to have one.
Thanks


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## Walterk (Jun 18, 2012)

Looks great!
And I love the idea of low-tech ramping up the output.
It would be easy to build something with the same effect with using resistance wire, a build-in variable resistor.
Wonder how QTC holds over time. QTC is the bomb if they give life-time guarantee. And no losses converted to heat!


How reacts the QTC when you stack 4 pads on top of each other, would that just require more force to get zero resistance?
Then it could also act like a variable resistor, also useful when you don't use QTC for a ramping-switch.
Less losses and easy to incorporate in a build, re-adjustable in case you change to the-led-of-the-moment.

Would love to hear that!


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## TheFraz (Jun 21, 2012)

Walterk said:


> Looks great!
> And I love the idea of low-tech ramping up the output.
> It would be easy to build something with the same effect with using resistance wire, a build-in variable resistor.
> Wonder how QTC holds over time. QTC is the bomb if they give life-time guarantee. And no losses converted to heat!
> ...



Thanks! So far the QTC is holding up great, and I've been turning it full off and on several hundred times a day to try and get it to wear out. But if if does eventually wear out, I've designed the engine where it should be very easy to replace the QTC with a new square. Simply take the old one out and drop a new one in - no tools required. However, I really don't think it will wear out during normal use only taking direct vertical (non-shearing) pressure. The company website claims something like one million compressions, and although that sounds a bit optimistic, I don't have any reason to not believe them. I haven't tried stacking the pads on top of each other, but yes I imagine it would work relatively the same but requiring more force to reach zero resistance.

Attached are a couple more videos showing the operation of the latest prototype. It now requires one full turn to reach full brightness. This makes it much easier to obtain a brightness level you're wanting - it also requires much less force to turn. It's a little difficult to tell in the video because of the camera's exposure changing as the light gets brighter (and the iPhone isn't the best camera), but you can get the idea. Also attached is a video showing the light being used outdoors.





-Fraz


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## ^Gurthang (Jun 21, 2012)

Fraz,

I'm even more impressed w/ your abilities, the newest prototype is VERY impressive. I like your idea of a nearly full turn to go from off to full on, an elegant UI. I'll keep watching enviously of your work. Good luck.


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## TheFraz (Jul 2, 2012)

Thank you for watching the progress ... persistence is definitely paying off on this one. I included a better quality video of the version 2.0 engine on the front post, but here it is again:



I really like the way it is turning out. Feel and size are much better now. I'm eagerly awaiting some new materials to come in for some new and interesting battery and materials combos. I've definitely learned how not to make a QTC light in a few dozen ways. 

-Fraz


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## Mattaus (Jul 3, 2012)

I've been following this thread from the beginning so I'm super keen to see where this heads....but if I can just ask a few questions and make some observations:

1) Awesome UI. The ramping is so smooth!

2) Does it need to be so...'fat'? Seems like the head is way over-sized for the optics, or is that a trade-off for the QTC functionality?

3) What size cell is in use in the light above? 

4) You're original design with the matching body sizes and notches was great - will that make a return?

I realise your latest version is a work in progress given the pen marks so I look forward to seeing it nearer completion!

Keep up the good work 

- Matt


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## TheFraz (Jul 3, 2012)

Mattaus said:


> I've been following this thread from the beginning so I'm super keen to see where this heads....but if I can just ask a few questions and make some observations:
> 
> 1) Awesome UI. The ramping is so smooth!
> 
> ...



Thanks for following Matt. To answer your questions, 
1)Thanks! 
2)It doesn't need to be quite so fat. It is that way now because of a few reasons. It uses a 26650 battery which makes it look a little thick, and it is short at around 4.5" which compounds that look even more (also I like overbuilt walls and tend to make them thicker than most). The head looks large because I am engineering this light a bit different from traditional design. All the guts, optic, heat sink, etc. go in from the tail end, so there is no bezel to screw on the top - I made it this way to limit the number of pieces in the design and the possible points of water ingress as much as possible. For this particular light however, I made the internal threading on the head a bit too long, thus the oversized look. Newer ones will have a shorter top section (I don't like the look of the shorter tail/body section as much).
3) 26650
4) Yes, the original design (or a variation of) will make a return when it is finished. This latest one was mainly an exercise in size reduction and engine tweaking to make it smoother. Aesthetics should look better going forward.

-Fraz


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## Mattaus (Jul 3, 2012)

Thanks for the answers. I'm still in line for one if and when you decide to sell them 

- Matt


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## TheFraz (Jul 3, 2012)

No problem - glad you still like the way they're going! Finished this latest one...looks different without the raw aluminum. Also the 'volume bars' for the brightness level now work, along with a marker bar on top to tell which level you have selected. Here's a pic:


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## Mattaus (Jul 3, 2012)

TheFraz said:


> No problem - glad you still like the way they're going! Finished this latest one...looks different without the raw aluminum. Also the 'volume bars' for the brightness level now work, along with a marker bar on top to tell which level you have selected. Here's a pic:



:twothumbs


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## gunga (Jul 4, 2012)

Looks great! Would love to see in another battery type. So, there is no circuit? This is direct drive?


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## TheFraz (Jul 4, 2012)

Thanks! I've got materials coming in this week for additional battery options - drawing out the plans now. Yes, no circuit board - so it is direct drive voltage-wise, with the QTC controlling amperage. Here is a video of the brightness control bars in action - it is finally a repeatable, stable, sustainable engine that can control the brightness with reasonable accuracy. The longest bar is 'off,' as well as 'high.' All the previous models had ghosts in the machine of some sort and would work correctly, but not exactly repeatable from one use to the next:



Please excuse my horrendous cinematography once again.


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## manoloco (Aug 2, 2012)

This is a very interesting thread, nice results TheFraz

Very interested to know more of it, specially if you decide to make it in other cell types and regulated.

Thanks for sharing your very nice work!


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## ^Gurthang (Aug 9, 2012)

Fraz,

Any news on your latest builds? Love to hear more.


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## TheFraz (Aug 9, 2012)

Progress is going good. I'm working on the AA version now, and I've made a few more key engine changes. In case you guys were curious, here's what QTC looks like after about 4k full compressions of various exposure times...







So the material can be too compressed and become deformed if it is exposed to large amounts of pressure for too long (it does still work approximately the same even deformed). However, I've since found a way around this little problem and added what I think is a good new feature to the engine - a fail safe that puts the light into direct drive when it gets to it's maximum level of safe compression. This should keep it from deforming. I'll keep you updated. Thanks for following the project!

-Fraz


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## TheFraz (Aug 20, 2012)

I had time to take a couple short videos demonstrating the fail-safe in action. In the videos you can see the light switch to direct drive (when it slightly jumps in brightness), bypassing the QTC, when it reaches a certain level of compression. As you can see the light looks a bit beat up - the results of the torture testing the prototype has been going through. It holds up very well to drops and all kinds of everyday use so far.




The first video, the light is about 8 feet away from the door. The 2nd video it is about 20 feet to the wall.

-Fraz


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## Mattaus (Aug 20, 2012)

Looks good 

Any reason why you have to do so much turning before it starts to power up, or is that just how far you had it unscrewed in those particular videos?


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## TheFraz (Aug 20, 2012)

Thanks! I'm turning it more initially because I've gotten into the habit of turning it an extra twist in the "off" direction to make sure it doesn't stay on a very low mode unintentionally. The full brightness range is still one full turn.


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## gunga (Aug 20, 2012)

I'm interested. This is direct drive right? So when you say AA do you mean 14500?


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## TheFraz (Aug 20, 2012)

Yes, it's direct drive voltage-wise. However the QTC acts as a great variable amperage 'driver.' It has great run times because of very small losses. 

The AA version will be able to use a single 14500 or 3 x regular cells (with a 2nd body option).


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## TheFraz (Sep 3, 2012)

Upgraded the engine again and reduced the length of the light to 4.3". Also did a drop test this afternoon from approx. 25 feet to concrete. The light passed no problem (not bad for a 255 gram light with no rubber bumpers - the "crunch" when it landed made me cringe a bit). We're going to go for a 50 foot drop onto concrete next, and hopefully keep going higher.
Here's a video of the current drop:


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## TheFraz (Sep 5, 2012)

And here's the drop test from 50+ feet to concrete. The light passed again. I suspect it will be very difficult to get this build to fail because it has very few weak links. I think the most likely scenario is battery failure, but with the battery trapped between two springs and tightly hugging the sides of the tube, that is unlikely to happen as well. We're gonna try to find a 100' drop next and keep on going up til it fails. As of this point I feel pretty good about the durability of the design.

Here's the video. If you look closely you can see the light dropped right after I say "alright." (we jumped the gun a bit on the drop lol). It lands on the path and bounces into the grass..


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## Empire (Sep 5, 2012)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*



TheFraz said:


> Hello all,
> 
> Long time lurker here. Decided to post this as I am very pleased with the way it has turned out.
> 
> ...



I WANT ONE!!!!!!!!!!!!!!!!


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## Mattaus (Sep 6, 2012)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Looking very good


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## TheFraz (Sep 14, 2012)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Finished the third engine and body prototype today. Hopefully ironed out the last batch of bug fixes and added an xm-l neutral. I like the action of this one better - it doesn't require a full twist to max. It is also the shortest one so far at 4.0" even. Here is a pic (of the light next to a tk41) and video...even though all the videos look relatively the same. It is tough to gauge the brightness ramping because of the camera changing exposure.

edit: put up a video of the new light against a tk41 in bounce....just for something different.


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## TheFraz (Jan 5, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Haven't posted in a while, thought I'd add an update. Got a chance to use my prototypes a lot over Christmas while our power was out for almost a week. The 26650 burned the whole time without a recharge (on mostly medium levels)...gotta love that extra capacity. Also updated the engine again and it's getting 5k+ full turns pretty easy without deformation. Here's a pic of the upgraded 26650 light I used in the power outage:






And here's a few pics of the prototype progression at this point with a MAg at the end for size reference.














The silver one at the end is an 18650 version of the 26650 light using the same engine. The 3rd one from the left is a bit beat up from drop-testing.

-Fraz


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## TheFraz (Jan 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Finished another prototype. This time I tried my hand at anodizing with some decent results. I've gotten this 26650 version of the light down to around 3.7" and cut some weight as well. Below are pictures of the new light as well as the first prototype (both 26650 versions) so you can see the size difference. This new one is completely redesigned on the inside - I like the way it functions a lot better. Here's the pics:











I'll get up a video up of this new prototype soon. Aesthetically I like the way it looks better than the old version.

-Fraz


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## Megatrowned (Jan 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Ooo, it's shiny! And I like the way it looks too :thumbsup: What makes the 'feel' of this one better than the last?


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## TheFraz (Jan 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*



Megatrowned said:


> Ooo, it's shiny! And I like the way it looks too :thumbsup: What makes the 'feel' of this one better than the last?



Thanks!  Yeah, I like the shiny look...it's a change. The pressure it takes to change the brightness feels more intuitive now - it's been tough to get it right. I didn't want the light to be too difficult to turn...but it couldn't be too easy either or it would risk accidental activation. It also has a better weight and feel in the hand in my opinion.


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## xevious (Mar 24, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Looks to me like PEAK LED Solutions is the only commercial outfit putting QTC to serious use. I'd heard their Gen1 design was resulting in premature QTC failure, but the Gen2 design has supposedly solved this. So, it's very intriguing to see someone else come up with a design that maximizes QTC life. Is the QTC fairly easy to access and replace in your light? I'm thinking that if this is so, one can always stock up on QTC and replace as needed... and if once every year or so, that's not too bad.


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## Darvis (Mar 24, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

I would be all over this in brass and/or stainless steel... copper!?? 

Subscribing to this thread


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## TheFraz (Mar 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*



xevious said:


> Looks to me like PEAK LED Solutions is the only commercial outfit putting QTC to serious use. I'd heard their Gen1 design was resulting in premature QTC failure, but the Gen2 design has supposedly solved this. So, it's very intriguing to see someone else come up with a design that maximizes QTC life. Is the QTC fairly easy to access and replace in your light? I'm thinking that if this is so, one can always stock up on QTC and replace as needed... and if once every year or so, that's not too bad.



Yes, it has been one of my main goals to prolong the longevity of the QTC pill. It is quite difficult to get it right - but after destroying about 100 pills, gradually extending their life each time, I think I've come up with a good solution (the other good thing is that if the QTC were to ever completely fail or disintegrate, the light would still function). I also developed this light with the idea of making the pill easily user replaceable - so although it should last a long time, it is possible to replace the pill if you wish.

Darvis, I just sent in schematics to a shop to do a run of these lights, so they will be for sale soon. Just before they are ready (hopefully in a few weeks) I'll post a sales thread. Currently they are going to be 6061 aluminum and anodized HAIII, but I will check into using other materials as well. I will also describe more intricately how the light works in the sales thread - it uses a very unique engine that should make it very durable. Thanks for checking out the progress!

-Fraz


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## octaf (Mar 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Any plan for Ti host ? Hopefully utilizing 18350.


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## TheFraz (Mar 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*



octaf said:


> Any plan for Ti host ? Hopefully utilizing 18350.



I'm currently working on a couple other models using different battery configurations (most recently a single rcr123/cr123 type). As far as the Ti, I haven't worked with that material yet, but I don't see why one couldn't be made. I'll discuss it with the machine shop.


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## Megatrowned (Mar 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

This is interesting! Let us know possible prices as soon as you know  Will have to add this to my want list!


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## xevious (Mar 27, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*

Good to hear it, Fraz. I'll keep my eyes open for your thread.


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## octaf (Mar 28, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0 v*



TheFraz said:


> I'm currently working on a couple other models using different battery configurations (most recently a single rcr123/cr123 type). As far as the Ti, I haven't worked with that material yet, but I don't see why one couldn't be made. I'll discuss it with the machine shop.



Good to hear that.

18350 is almost the same as 16340 or CR123, just a little bit fatter, or thicker. 

These days, I see lots of factory made CR123 lights actually having enough room for 18350 in their battery tube.


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## TheFraz (Mar 30, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0*

Here is a video I've been meaning to make for a while of the latest prototype. One of the things I am most pleased about is the size. At around 3.7" it is very small for a 26650 light that has a battery spring on both ends and an optic...at the beginning of the video I compare the size to a Wolfeyes Sniper (an 18650 light). The lower levels of brightness are shown at the beginning (they are usually the first to act up with QTC), then I show the full brightness on the wall and in the yard/grass. The engine build shown in this video is the best I've made so far - the piece of QTC inside is well used but not showing any visible imperfections in brightness ramping.



-Fraz


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## xevious (Mar 31, 2013)

*Re: QTC flashlight - from scratch (non battery-crush)...now with engine version 2.0*

Excellent! You weren't kidding--the ramping is _extremely_ smooth. I've seen videos of Peak's QTC lights that aren't this smooth.


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## Diablo_331 (Apr 9, 2013)

I've personally been very disappointed with Peaks gen1 and gen2 qtc lights. Granted I've only tried the Eiger and I've heard that the larger Peak lights tend to be smoother. My current neck light is a 40DD and the ramping is very smooth. I'm very happy with it. 

This project looks to good to pass up! Good look going into the production stage! I've followed this thread from the very beginning and if funds allow then I'll be picking one up.


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## ^Gurthang (Apr 10, 2013)

Fraz,

Glad to see your latest prototype, very nice work and the ramping looks smooooooth! Keep up the good work, I'll keep checking on progress.


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## TheFraz (May 2, 2013)

Thought I'd post a picture of my latest build. Added some knurling on the ends and HAIII. This one is also completely waterproof. I'll add a pic or video of it's use underwater later.







-Fraz


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## xevious (May 2, 2013)

^ Nice, Fraz. Me like! :thumbsup: Is that a lanyard slot in the tail cap? Would definitely help with anti-roll.


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## TheFraz (May 2, 2013)

xevious said:


> ^ Nice, Fraz. Me like! :thumbsup: Is that a lanyard slot in the tail cap? Would definitely help with anti-roll.



Thanks  Yes, that's a lanyard slot. When the lanyard is in it does prevent rolling.


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## gunga (May 2, 2013)

Very cool! I echo the comments on peak lights. Great sometimes, but never stay consistent. The design is just not good enough to optimize qtc usage.


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## TheFraz (May 4, 2013)

gunga said:


> Very cool! I echo the comments on peak lights. Great sometimes, but never stay consistent. The design is just not good enough to optimize qtc usage.



Thanks! And I've never used a Peak - but I do know that it is very difficult to make QTC work well over time. I've designed this one from the ground up around QTC, and it's taken dozens and dozens of failures to get it to a point I feel like it works the way I imagined.

Here is a video I talked about the other day of a water test for the new prototype. I dunk it in the bathtub (around 1.5 feet of water) and then use it. I feel great about the water resistance of this light. It only has two possible points of ingress - and both are very snugly o-ring sealed. I think it will be able to handle a significant depth with no problem. Hopefully I can go to the lake soon to try it out.

I've also attached a picture on the front page of the prototype progression.

Water test:


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## gunga (May 4, 2013)

Can you make a smaller version? You'd sell lots!


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## TheFraz (May 4, 2013)

gunga said:


> Can you make a smaller version? You'd sell lots!



Yes, I'm working on a smaller version (cr123) now. It should be very small...I'm thinking somewhere around 2.5" long.

This current 26650 version might be a bit smaller than it seems - it's 3.91" long. My goal was to make these lights very compact, simple, and sturdy. And I like the 26650 platform because of the insane run times on pretty much all levels. It definitely has some weight for it's size because of the need to heat sink a lot of energy at the direct drive fail-safe.

Here's a pic of the matte 26650 light beside a 26650 battery for reference. So yes, I'm hoping the CR123 version is tiny


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## TheFraz (May 21, 2013)

Here is an interesting picture I got to take this last weekend. Had a chance to go to the lake and drop the light off the boat dock into 10 feet of water - below is a pic where you can see the leaves/mud on the bottom. Also got to lower it about 20 feet off a boat, but couldn't get a very good picture - I plan to go back and get a better picture of the light in the deeper water.


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## xevious (May 24, 2013)

That's great! What a cool shot. If you weren't told what it was, you'd think it was someone using a flashlight in the woods during a dense fog, with no clue that it's under water.  So it certainly looks like the casing is nice and water tight. Do you think you'll have a go at some further pressure testing? Would be interesting to see if this design could cut it for a dive light to 50M.


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## TheFraz (May 27, 2013)

xevious said:


> That's great! What a cool shot. If you weren't told what it was, you'd think it was someone using a flashlight in the woods during a dense fog, with no clue that it's under water.  So it certainly looks like the casing is nice and water tight. Do you think you'll have a go at some further pressure testing? Would be interesting to see if this design could cut it for a dive light to 50M.



Thanks! Yeah, I want to test it deeper and deeper until it takes on water if possible. This lake only goes to around 50 feet or so, but I can probably find some places to test deeper. It should hold up well since it only has two possible points the water could get in - and both have very tight and large o-ring seals. I don't think I'd want someone to rely on the o-ring holding up (since the main o-ring receives some wear from the twisting action) for diving, but if the light is dropped deep in a pool, river, or lake, or even if someone swims with it, there shouldn't be any worries.


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## TheFraz (Jun 19, 2013)

I finally got a small run of the lights finished. Added a couple more small changes that were mostly aesthetic (rounded corners to reduce wear), and a few small internal changes. Below are some pics of the new lights. The left one is regular and the right is matte black. Also got a chance to take some interesting beam shots. There was some construction around the area under the Interstate 430 bridge over the Arkansas River in Little Rock, AR and the electricity was completely out. Gave me a chance to test out the brightness in a setting with not much ambient light. I thought it was also interesting to get a more urban set of beamshots in pitch black when I'm used to only being able to find complete darkness in the woods. The area under the Interstate bridge is huge - almost like a gigantic cave. Pics are below.


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## euroken (Jun 19, 2013)

I would be interested in a matte black one if you decide to release them for sale. 

Cheers


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## TheFraz (Jul 5, 2013)

euroken said:


> I would be interested in a matte black one if you decide to release them for sale.
> 
> Cheers



Euro, I am about to start a sales thread for these lights over in the CPF Custom B/S/T area.

Also, I wanted to show some elements of the light that make it unique that I have not yet shown. The internals:


















These pictures better illustrate how the light operates. The middle 2 pictures are the first ones I have shown of the engine. 

It is a pretty unique system. As you can see, it is a piston system that makes contact with the lip of the battery tube, which allows the light to use double springs and completely eliminates shearing forces. This is what makes the light non-battery-crush. There is no pressure on the battery. The functional parts of the engine are actually around the optic, which allows the light to have such a short length. The optic system is set into the heat sink itself, which allows the heat to dissipate pretty rapidly through the body of the light. The outside of the light only has two points where water can enter. The optic, and the battery tube. Both are sealed very tight - when the engine is threaded in, the final turn creates a tight seal from the lip of the bezel around the edges of the optic. The battery tube has a very thick o-ring that holds up well to heavy use. I have tested the light to 70 feet in a lake and it has no problems....it should be able to go much deeper. It also holds up very well to impact because of the lack of breakable parts. The pistons themselves are designed to protect the QTC and keep it in place. They work very well to eliminate the flickering and artifacts that are common with QTC lights.

So there you have it with the internals. I've changed them up so many times, I haven't posted the solution til now. But I feel like this is by far the best version of the engine. So I have made a run I will put up on B/S/T later tonight. Thanks for following the thread guys! 

-Fraz


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## jabe1 (Jul 5, 2013)

The QTC is between the brass rods in the light engine? So to change it, remove the screw, lift the larger rod section, and push the shorter section up to reveal it?

Nice....


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## TheFraz (Jul 6, 2013)

jabe1 said:


> The QTC is between the brass rods in the light engine? So to change it, remove the screw, lift the larger rod section, and push the shorter section up to reveal it?
> 
> Nice....



Correct, the QTC will be replaceable using much the same process as you described. The engine is designed so it can be unscrewed from the light body using needle-nosed pliers (you can see the holes for the pliers in the 2nd picture). Removing the screw will allow the pistons to be extracted from the top of the engine. However, the QTC has a surprisingly long lifespan when used in this system...it is guarded against overcompression which tends to damage it the most in my experience. I like to picture the piston system as similar to a hydraulic - it traps the QTC in a way so that even when damaged it performs approximately the same. I hope that it is a very long time before the QTC pills need to be replaced.


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## TheFraz (Jul 11, 2013)

Couple interesting new torture-test videos...


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