# Marwi Light Mod



## Uzzi_PA (Dec 15, 2009)

Has anyone else modded these lights? I've recently put together a light using an old style Marwi housing and clamp and a Cree LED. I have found that it's very very cheap and fairly simple to build. It also runs extremely cool, has a long battery life off of normal AA's, and has multifunctional settings.

The reason I chose this setup is, I used to have a Marwi dual halogen setup using the same light when they first came out, but the battery and bulbs died. I loved the Marwi lights when they were working, and I used to guide my riding buddies back to the trailhead when we get caught in the dark on dusk rides. I recently got the LED bug and have been weighing my options. I'm also on a shoe string budget and couldn't afford anything retail, other than a basic commuter light.

I got the idea after seeing the success El34 has had, but I wanted to make my own heatsink and optics, because I like designing stuff and wanted to see if I could pull it off, without any help from a machine shop. All I used were spare parts from around the shop, and simple tools like a hacksaw, files, grinder, etc.

My setup is:

Old style Marwi "bell" light, with matching old style handlebar mount.

Current regulator: DX-6190 5-Mode 1-amp board

LED: Cree XR-E Q5 star

Heatsink /adapter: Scratch made from copper pipe

Optics: lens from a low power LED flashlight, and reflector from a incandescent flashlight.

Battery: 3 NIMI AA cells, In a PVC pipe and flashlight springs and caps. Velcro strapped to the top tube.

I got the light from www.hoffmanamps.com and the electronics from www.Dealextreme.com Everything got to me in a week, so I'm pretty happy with both vendors.

Total price: $30

Build time: maybe 4-5 hours.

The challenges in this project were the adapter/heatsink and the optics.

The heatsink required me to cut a copper pipe in half and pond it flat, lapp it smooth and grind to the inner diameter of the light, to make the forward facing star mount.

Then I had to take a 3/4 " pipe and chop it to the right length, then make 3 cuts through it at 120 degree intervals. Then I broke off 2 of the flaps and bent the remaining 4 out slightly and took another pipe and fed it through the first and pounded it to till it had a flat surface

I then took the 2 parts and soldered them together with a torch, did some tweaking on the roundness of the rear flanges and drilled holes for the star screws and wires.

The optics were tough since the halogen bulb and lens are fused together and the total length, even if I cut the light out of the reflector it's too long for the heatsink. Instead, I grinded down a plastic lens, and took a plastic flashlight reflector and grinded it down as well.

Installing the electronics was easy once I figured out the wiring layout of the regulator. With everything mounted and wired up it works as well as my old 12W halogen, but with 5 modes and a very bright, long distance spot in 3W mode. I plan on adding a second beam, with flood optics and use a P7 or XP-G, but I don't need that kind of setup right now.


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## mojojojoaf (Sep 9, 2008)

EI34 has a nice conversion kit- he uses the SSC P7 led- I have two of them. Work great.


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## Cat-man-do (May 16, 2004)

Uzzi_PA said:


> *Has anyone else modded these lights?* I've recently put together a light using an old style Marwi housing and clamp and a Cree LED. I have found that it's very very cheap and fairly simple to build. It also runs extremely cool, has a long battery life off of normal AA's, and has multifunctional settings......
> 
> .....*I got the idea after seeing the success El34 has had*, but I wanted to make my own heatsink and optics, because I like designing stuff and wanted to see if I could pull it off, without any help from a machine shop. All I used were spare parts from around the shop, and simple tools like a hacksaw, files, grinder, etc.


You have to love the look of the old Marwi halogens. I applaud your effort to make a simple heat sink to work with the XR-E's. Since I have a lot of old Marwi stuff at some point I might try my hand at DIY ( even though I have WAY too many bike lights now.)  
The problem is there really is little incentive to cobble together a light seeing there are many cheaper alternatives. I am surprised though that you didn't chose to buy the P-7 kit from EL-34. With the kit you have everything you need ...heat sink, reflector, led , switch..etc..everything but the batteries and holder and you can get those from him too. Last I checked he had run out of the drivers so without the drivers you would be SOL. 

(( *** EL34*...If your out there and are still making those drivers let us know.. ))


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## El34 (Jan 11, 2009)

If you love those old Marwi lights, then you need to look at my web site here.
http://www.el34world.com/Misc/bike/BikesLights1.htm

I sell a P7 heat sink for those lights

store link is below


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## Uzzi_PA (Dec 15, 2009)

Thanks for the advice guys. 

You’re right about the price, I could practically get a Magicshine for a little more than I paid, but what’s the fun in that. This way I learned a lot about the tech, and was able to customize it.

I'm definitely going to try something like that for my next project. using a much brighter LED setup, and El34's conversion kit. Once it warms up I’ll want more light for night rides. 

These old Marwi's are great because they can be mounted side-by-side on the same swivel mount and have full independent adjustabliIity; up and down and can even be twisted side to side for any handlebar offset. My idea is to have a XR-E spot/lowbeam, and 3 x XP-G's flood/highbeam. 

I figured the low beam was a good place to start. I’m just commuting with this light, so I wanted a light that’s medium brightness for good visability and low maintenance. Using a P7 wasnt the best choice for this application. I also wanted something I made myself, so I understood how it worked and for the satisfaction.


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## Uzzi_PA (Dec 15, 2009)

*New Light Time!*

Hi guys, I finally got my little XRE light working well enough to take it for a full-on night ride in the park. I replaced the junk home made optic with a DX 35mm reflector. Its now just enough light to pierce the darkness, but it's such a tight beam, I could only see a few seconds in front of me, which was a bit scary, going down super steep rooty and rocky down hills in the drizzling rain.

So now that I have usable light; why not rip it apart and build it into a new one? I'm making a dual XML out of it, which should give the night a run for its money.

I'm thinking it will work best with one at 3A with a narrow optic for the high beam, and the other at 1A and a wide optic for the low beam. I'm still waiting for the XMLs so I can see how they work with the DX reflectors. I cut one of the reflectors in half length wise so it makes more spill, and it looks good with the XRE.

Here's what the Old style dual Marwi looks like put together, but gutted out. You can see the new home made copper slug in the left side, which neatly press fits in, using some fancy soldering.


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## MHC (Oct 23, 2009)

Detail of my Marwi LED conversions here http://forums.mtbr.com/showthread.php?t=661040


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## SBJohn (Feb 5, 2010)

Uzzi_PA
I have a couple of Marwi light bodies just waiting for my attention. Now, I'll fashion a heat sink like yours. Very clever.:thumbsup:


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## Uzzi_PA (Dec 15, 2009)

The drivers and LEDs arrived last night so I was excited to start building it up. Here's the new setup:

Drivers: AMC7135 2800mA 5-mode, and AMC7135 1050mA single mode 

LEDs: 2 XML-T6, 1D bin emitters

Optics: 2 DX 35mm reflectors.

Housings: 2 Marwi/Viewpoint bodies, with old style mount 

Batteries: 2 Trustfire18650 2400mAh Gray, with home made parallel holder

2 Home made heat sink adapters; I made by cutting and bending/flattening copper pipe, then pressing the cylindrical part into the Marwi body (this part is critical for a tight fit) and using a torch to solder the flat part on.

Total cost of this build, minus wire and tools: around $115.

I purchased the parts from DX, hoffmanamps and Illuminationsupply

The build-up went pretty smoothly, I used arctic alumina adhesive to mount the emitters, instead of screws and thermal grease. I wired up the 2800mA driver using the 3 mode setting, so i get 150mA, 1000mA and 2800mA. The reflectors worked out better than expected; I had to shim both to got them to the right position, but the XMLs project a much larger light pattern that the XRE, so there is no ringing to the flood beam and the narrow beam is very bright in the center, but fades into tons of usable spill. I placed some tape over the top of the spotlight so its more friend to pedestrians.

It appears to be outputting the full amount of light and in distribution I had intended. That means about 400Lm out of the flood beam, and 870Lm for the spot light.

I'll post some beam shots, once I get everything focused just right.


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## El34 (Jan 11, 2009)

Pretty cool!

More Marwi's live on.


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## Uzzi_PA (Dec 15, 2009)

Ive just finished designing a new set of reflectors. The main one uses a reflective shroud, which reflects the light down, right below the focused part of the beam. I originally used a piece of electrical tape, but the 900 lumens started melting the black plastic, so I tried this trick and it worked so well I don't even need the second light head I built to point down and make a flood beam. 

I couldn't get my point and shoot camera to do night shots, so no beam shots. I did draw a simulation of the beam pattern which you can imagine, when spread down the trail creates a large flood area that works well, even on the 1 amp setting.


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## Uzzi_PA (Dec 15, 2009)

Finally got my camera to cooperate. I set it to ISO100, Daylight, and EV Shift +2 to get as close as possabe to MTBR settings, with my point and shoot camera.

I setup some sticks at 10, 20 and 30 feet.

The light works great, and I only need to use the high setting when going really fast, otherwise the 1000mA setting works just fine.


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## mfj197 (Jan 28, 2011)

Looks good, Uzzi_PA. Nice reflector design.


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## Magnum9 (Jun 8, 2011)

I am looking at doing the same thing with the reflector below from cutter, what material did you use for the flat reflector?

Cutter Electronics


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## Uzzi_PA (Dec 15, 2009)

I used a piece of chrome plated copper or tin. It was a candle lid originally. I picked it because it was easy to cut and has a really nice finish.


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## mntn-biker (Sep 12, 2010)

Do you cycle thru your 5 different modes by simply clicking the light on and off with your switch? Also, I see on the IlluminationSupply website, the description of that 5 mode driver states, "Customers can request to have their board jumpered to 5/30/100 - just note it in the order". I'm assuming if I don't want the strobe and SOS option, only the 3 different light powers, I would ask for this? I don't see a Cree XM-L T6, 20mm star MCPCB on their site. Did you order that from someplace else?

Speaking of the driver, is this the one you have:

8xamc7135-28a-selectable-mode-driver


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## Uzzi_PA (Dec 15, 2009)

Yep, the driver is pretty simple; like you said, it switches modes by turning the light off for a split second. With the Marwi switches, you can tap the switch slightly and it changes without having to fully click it off.

I didn't get mine pre-wired, but its an easy mod, because the board has pads on it that are easily connected, and you can select from several different configurations.

You can get it from IlluminationSupply or here too for less, but it will take a while to arrive from China. http://kaidomain.com/ProductDetails.aspx?ProductId=10995 The emitter probably sold out, their inventory seems to change alot, and I was lucky to get a decent bin there.


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## mntn-biker (Sep 12, 2010)

Uzzi_PA said:


> Yep, the driver is pretty simple; like you said, it switches modes by turning the light off for a split second. With the Marwi switches, you can tap the switch slightly and it changes without having to fully click it off.
> 
> I didn't get mine pre-wired, but its an easy mod, because the board has pads on it that are easily connected, and you can select from several different configurations.
> 
> You can get it from IlluminationSupply or here too for less, but it will take a while to arrive from China. http://kaidomain.com/ProductDetails.aspx?ProductId=10995 The emitter probably sold out, their inventory seems to change alot, and I was lucky to get a decent bin there.


Did you have to remove the spring on the driver? Seems like it might get in the way with the lack of space we have in our Marwi newer style housing?


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## El34 (Jan 11, 2009)

Guys, thanks for the heads up on the 2800ma driver board.
I was not aware it was out there cause I never go to Kaidoman site.

I have been making my own from two of the AMC7135 - 1400ma boards

Question: I see that you can solder to the different stars and get access to the different modes. I am guessing that you use a *Normally closed SPST switch*, correct?

Then when you press the switch it breaks contact and changes modes, Correct?

Just asking if it's NC switch cause I already stock those, if not, I will have to get some Normally open switches (which I need to stock anyway)

Thanks for the info


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## Uzzi_PA (Dec 15, 2009)

I did attempt to remove the spring by heating it up with a 50W soldering iron, but its on there pretty solid and I wasn't able to get it to budge. it didn't matter for me, because my bell style housing has all kinds of room in the back for wires, springs, powerbars, etc...


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## Uzzi_PA (Dec 15, 2009)

El34 said:


> Question: I see that you can solder to the different stars and get access to the different modes. I am guessing that you use a *Normally closed SPST switch*, correct?
> 
> Then when you press the switch it breaks contact and changes modes, Correct?
> 
> ...


I'm using a Judco SPST Switch, so its a normally open switch, and to change modes I just tap the switch half off.

I do like you're driver mod, its simple and solid. These drivers are smaller though, and that may be a deciding factor.


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## mfj197 (Jan 28, 2011)

Either a latching SPST (single-pole single-throw) switch or a momentary normally-closed (NC) switch would work. It only has to momentarily interrupt the power supply to change modes as it is inline with the power supply. A latching SPST would latch open or closed so you'd be able to turn it off completely via the switch, whereas a momentary NC switch normally keeps the power connected but momentarily breaks the power when pressed. Note that most momentary switches are normally-open which would not work - the light would only be on whilst you were holding the switch in and it would go off again when you let go.

Uzzi_PA, I don't think yours is a normally open switch - I think it's a standard latching SPST. It latches either open or closed, but you can temporarily break the connection by half-pressing it (known as a reverse-clicky in flashlight-speak!).


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## El34 (Jan 11, 2009)

Ok thanks
Yes the Marwi type Judco SPST's are Normally closed, not open.

So the switch does not have to be rated at whatever the LED current draw is, correct???
In other words, the whole battery current does not flow through the switch??

A NC momentary rated at 2 amps would work just fine (I already stock these)

The reason I am interested in these boards is that I have come up with a heat sink for the new bullet style Marwi's.
There is way more room inside the bullet housings.
It takes me quite a while to assemble the dual 1400ma drivers.
This would save me a bunch of time.


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## mntn-biker (Sep 12, 2010)

El34 said:


> The reason I am interested in these boards is that I have come up with a heat sink for the new bullet style Marwi's.


Really??? :thumbsup: Are you talking about the insert, not the actual 20mm star MCPCB?

I may be interested if I can't come up a lathe I can "borrow" to make my insert. Here is what I am coming up (in theory) for my stackup. I would like to find a larger diameter MCPCB so I can get my mounting screws outboard more. The Fraen FRC reflector is plastic so I can get that reflector right down close to the MCPCB the way it is designed to work with the LED.


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## mattthemuppet (Jul 16, 2004)

I think 20mm MPCBs are as big as it gets for standard LEDs, but if you want to do away with screws lots of people use Arctic adhesive (can't remember the exact name) with a lot of success. It's not like you'll need to swap the LED out in the future.


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## mntn-biker (Sep 12, 2010)

mattthemuppet said:


> I think 20mm MPCBs are as big as it gets for standard LEDs, but if you want to do away with screws lots of people use Arctic adhesive (can't remember the exact name) with a lot of success. It's not like you'll need to swap the LED out in the future.


I just thought it would be nice to have it screwed in place so that I could experiment with different LED's. This would appear to be a good "Plan B" though I must admit.

Is this it? It states, "Arctic Silver Thermal Adhesive was formulated to conduct heat, not electricity."

arctic_silver_thermal_adhesive


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## mfj197 (Jan 28, 2011)

El34 said:


> Ok thanks
> Yes the Marwi type Judco SPST's are Normally closed, not open.
> 
> So the switch does not have to be rated at whatever the LED current draw is, correct???
> ...


The way these switches are normally used the switch does need to be rated for the full LED current flow, so a NC momentary rated at 2A wouldn't be sufficient for an XM-L at full chat. The full battery current flows through the switch which is inline between the battery and the driver. It is however possible to wire it another way - have the switch in the positive lead from the batteries to the driver but wire the positive from the LED directly to the battery (not via the positive on the driver). That way the switch is only switching the power to run the microcontroller and AMC7135 chips on the driver, and not the LED power itself. Let me know if you need a circuit diagram for that.

From Uzzi_PA's description it sounds like the Judco switches are latching, which means they are neither normally open or normally closed (those descriptions only refer to momentary switches). Latching switches toggle between one state and the other.

By the way, Shiningbeam in the US has these drivers as well. I've bought two from them and they were shipped to me in the UK very quickly.


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## mattthemuppet (Jul 16, 2004)

mntn-biker said:


> I just thought it would be nice to have it screwed in place so that I could experiment with different LED's. This would appear to be a good "Plan B" though I must admit.
> 
> Is this it? It states, "Arctic Silver Thermal Adhesive was formulated to conduct heat, not electricity."
> 
> arctic_silver_thermal_adhesive


that's the one


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## Uzzi_PA (Dec 15, 2009)

i did mean 'normally closed' for the switch. I haven't had any problems running the switches at 3A, I used 20G wire and trail-tech plugs and haven't had any overload problems yet. 

I used arctic alumina adhesive for this project and it worked out great; no need to find tiny screws, get the holes perfectly aligned, or make space for them behind the lens. All I had to do is get the heatsink fit to the right depth in the housing; mix the stuff; blob it on to the heatsink and fit the LED and lens into the housing and it pretty much aligned its self.


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## El34 (Jan 11, 2009)

Originally Posted by *El34*  
_The reason I am interested in these boards is that I have come up with a heat sink for the new bullet style Marwi's._




> Regarding Bullet style Marwi housing heat sink
> Really??? :thumbsup: Are you talking about the insert, not the actual 20mm star MCPCB?


I should have said that I have come up with a heat sink for the reflector and P7 that I use.
The slug has to sit back into the cone shaped area of the housing and so the slug has to have a 14 degree angle to fit back there.
It will be glued into position using a thermal adhesive so that the heat can conduct to the outer shell.

I did not think I could glue it into place and have it work properly, but the adhesive transfers heat very nicely.
Doing some more test in a few days to see how well it all works.

Here's what the slug looks sitting in the housing and what the whole stack looks like. Slug - P7 - Reflector


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## BrianMc (Jan 5, 2010)

Nice EL34. Very Nice. I wonder what an XM-L would do with that reflector? The H6Flex won't fit, and the stacked DX driver may be tight for fitting the tail with switch, but your direct drive option and the LFlex should fit.

BrianMc


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## mntn-biker (Sep 12, 2010)

A Fraen FRC reflector would give you more room at the rear of the newer style housing (for a driver and wires) and being plastic, you would not need to worry about shorting the LED if the reflector ever had the chance to touch it. They make them for the SSC P7 LED's. You might wind up with a disc/insert that does not need to be tapered. Having the taper might not get it seated properly and might give you a mis-aligned LED. Having as much straight wall as possible would be best for alignment purposes. Just thinking out loud here.


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## El34 (Jan 11, 2009)

> A Fraen FRC reflector would give you more room at the rear of the newer style housing (for a driver and wires)


PLenty of space out back in the Bullet housings. They are not like the old housings. I could stack 3 or 4 boards behind the heat sink, no problem.



> and being plastic, you would not need to worry about shorting the LED if the reflector ever had the chance to touch it.


I am not crazy about using plastic parts. The aluminum reflector I use is actually another heat sink source and the beam shape is great.



> Having the taper might not get it seated properly and might give you a mis-aligned LED.


I have an alignment tool that holds the slug in perfect position while the *silver based* adhesive dries. The adhesive can sink the heat and stay put, no problem.

The LED can't short on the refelctor. It can't tip side to side. 100 or so Marwi P7 builds later and not one short.



> I wonder what an XM-L would do with that reflector


Don't know. Would like to experiment with one. Post me a link for an XML that everyone here likes to use?

DX or Kaidoman preferred since I have accounts there already.


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## BrianMc (Jan 5, 2010)

If setup right, the screw-on bezel will apply pressure through the reflector against the MCPCB, holding the beveled sink/firewall in place. I use that method to press the tapered ends of three different designs of copper pipe sinks hard against the Al in the cone tail. Works like a charm. Just AA paste, no epoxy. 

The issue I see, is that the body wall is thinnest at or just forward of where you can see the MCPCB through the slot for the cone/mounting lug. I get very little temp difference along the body of the these lights with transfer both in front and behind the thin spot, but I haven't tried it with the transfer in the tail only. There is only about 7 inches of area for about 9 watts of heat at 3 A it is all needed, back off to 2.5 A or so the 'sweet' spot output versus heat wise for an XM-L and it will be fine. 

Whether the thin spot is limiting enough to need attention, I don't know. It is also a long thermal path to the front of the light and the lion's share of radiation surface is forward of it. Be easy enough to find out if the thin spot causes enough of an issue to need help.If it is an issue, it would be nice to use the reflector as a second thermal path, and/or a ring bulkhead encircling the MCPCB and for a thermal path straddling the thin spot using thermal paste and a good fit. 

BrianMc


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## El34 (Jan 11, 2009)

> If setup right, the screw-on bezel will apply pressure through the reflector against the MCPCB, holding the beveled sink/firewall in place


Not good enough for me. 
The inside of the housing is not a perfect circle making constant contact with the heat sink.
The heat sink needs to be aligned and bonded and in constant contact all around with the housing, which is what the thermally conductive adhesive does.

I don't see any heat problems with plenty of air moving over the skin.
And most lights are used at night in cool temps.

At least for the type of MTB riding I do.

Commuters may have a different situation.

If you sit in one place with the light on high without any air moving on a hot night, then yes.

If you do that, you deserve to have your light blow up.


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## mntn-biker (Sep 12, 2010)

BrianMc said:


> and/or a ring bulkhead encircling the MCPCB and for a thermal path straddling the thin spot using thermal paste and a good fit.


No problem - we can do that :thumbsup::


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## mntn-biker (Sep 12, 2010)

El34 said:


> Post me a link for an XML that everyone here likes to use?
> 
> DX or Kaidoman preferred since I have accounts there already.


This is one that I am going to use based on what Uzzi_PA is using:

Cree xmlawt-1000


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## El34 (Jan 11, 2009)

I saw that XML at DX
Then I said, why does it cost less than other XML's I have seen??

Just curious, it seems to be $2 to $3 cheapers than some other XML's


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## BrianMc (Jan 5, 2010)

Another  sub $9, XMLAWT-1000?

EL34: you are correct. I used the springiness of the split copper to force the contact with compression. That won't play with a solid disc.

mntn-biker: That is similar to my copper pill and liner light. Works great, but is much heavier than needed.

BrianMc


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## mattthemuppet (Jul 16, 2004)

KD had T6s for around that price a little while ago, haven't checked for a while though. I get my U2s from there, much better service than DX and about the same price or cheaper.


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## mntn-biker (Sep 12, 2010)

BrianMc said:


> Another  sub $9, XMLAWT-1000?


I saw that one too but shipping to Michigan from Cutter Electronics in Australia is $13 

DX shipping is free. IlluminationSupply has a similar LED mounted on the MCPCB for $10 and they only charge $5 shipping from CA.

cree-xml-20mm-star-mcpcb-t5


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## Vancbiker (May 25, 2005)

If one has their heart set on a specific bin and tint, I'd go with Cutter even at the higher delivered cost. DX will send you an LED. It will be bright and some shade of white.


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## BrianMc (Jan 5, 2010)

FYI: If you need >$100 worth of items, Cutter has free shipping now.

BrianMc


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## mntn-biker (Sep 12, 2010)

mntn-biker said:


> IlluminationSupply has a similar LED mounted on the MCPCB for $10 and they only charge $5 shipping from CA.
> 
> cree-xml-20mm-star-mcpcb-t5


I have been in e-mail contact with Craig (the owner) of Illumination Supply and was inquiring about a brighter XML T6 and he suggested going with the same MCPCB but with the brighter XML U2 led on his site. It's $3 more but brighter and a cool white.

cree-xml-20mm-star-mcpcb-u2-1c-tint-p-75


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## El34 (Jan 11, 2009)

Question:
How come there are 6 solder contacts?
Are there 3 negatives all tied together and 3 positives all tied together?


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## mntn-biker (Sep 12, 2010)

El34 said:


> Question:
> How come there are 6 solder contacts?
> Are there 3 negatives all tied together and 3 positives all tied together?


Good question, we can probably assume that is true but I will e-mail the owner and ask.

On edit, I just heard back from IlluminationSupply and we are correct in assuming the above.


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## mntn-biker (Sep 12, 2010)

mattthemuppet said:


> that's the one


Do you think the Arctic Silver 5 thermal adhesive would work as well? It is primarily for CPU mounting but my local Radio Shack carries it.

Arctic Silver Incorporated - Céramique 2


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## El34 (Jan 11, 2009)

Supposedly, once you bond two surfaces together, it is permanent.
I don't mean like super glue, I mean like it is welding together.

I don't think they reccomend it for CPU heat sinks since you have to separate the heat sink from the CPU every once in a while??
More like a heat sink that you would never remove like a GPU or northbridge.

For LED heat sinks, I say yes, but not for mounting LED's
You may want to change out the LED someday.

If you never ever want to remove or separate two surfaces, then it looks to be the product of choice for thermal conductivity, IMO.


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## mntn-biker (Sep 12, 2010)

El34 said:


> Supposedly, once you bond two surfaces together, it is permanent.
> I don't mean like super glue, I mean like it is welding together.
> 
> I don't think they reccomend it for CPU heat sinks since you have to separate the heat sink from the CPU every once in a while??
> ...


What are you using for your thermal adhesive between your alum. housing insert and your LED star MCPCB that I see on your assembly instruction page?


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## El34 (Jan 11, 2009)

I am just now testing this adhesive - 98 5 star reviews

Newegg.com - Arctic Silver Alumina AATA-5G Thermal Adhesive



> When it absolutely needs to stay on forever, Arctic Silver's Arctic Alumina premium ceramic alumina adhesive is the way to go. This high temp adhesive will ensure that the heatsink will stick to whatever you attach it to.
> The ceramic composition means that there is no danger of a short circuit, unlike the silver based compounds. Arctic Alumina conducts heat away from sensitive components and improves the efficiency of your cooling system. Keep things cool and functioning under the hottest action!


There's also a more expensive version - 114 5 star reviews
http://www.newegg.com/Product/Product.aspx?Item=N82E16835100005


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## KBARK (Aug 7, 2007)

I've been using the AA that I got from LedSupply with good results. I haven't tried to remove any leds that I've glued down with it yet though. The heat sink in my recent builds is removable so I can always take it out then cut or sand away the dried AA and replace the led it I want to upgrade it in the future.

Also, if you use a optic like the Laura with a holder then screws seem to get in the way. That's why I prefer to glue mine down.


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## mntn-biker (Sep 12, 2010)

El34 said:


> Supposedly, once you bond two surfaces together, it is permanent.
> I don't mean like super glue, I mean like it is welding together.
> 
> I don't think they reccomend it for CPU heat sinks since you have to separate the heat sink from the CPU every once in a while??
> ...


Maybe I should still try to use a thermal paste/grease under the LED star and screw the star board down to the heat sink/housing insert. What grease are you using here - is there a product that works better or is thermal grease all the same?


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## mntn-biker (Sep 12, 2010)

KBARK said:


> Also, if you use a optic like the Laura with a holder then screws seem to get in the way. That's why I prefer to glue mine down.


That's what I'm afraid I'll run into when I start assembly.....


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## mattthemuppet (Jul 16, 2004)

well even if you glue the star down, you'll still have to trim an optic holder (like the one on the Laura) to clear the wires and solder on the pads. If you're already cutting 2 holes, it's not much harder to cut 4.


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## KBARK (Aug 7, 2007)

But, If you have a star that has + and - pads close together you can get away with only trimming one side of the holder.


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## El34 (Jan 11, 2009)

> Maybe I should still try to use a thermal paste/grease under the LED star and screw the star board down to the heat sink/housing insert. What grease are you using here - is there a product that works better or is thermal grease all the same?


I have used free CPU tubes that come with mother boards and stuff from DX in a small tub. Not sure brand makes a difference on the thermal grease.

Maybe Artic silver grease is better since it cost a bunch more?


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## mntn-biker (Sep 12, 2010)

mattthemuppet said:


> well even if you glue the star down, you'll still have to trim an optic holder (like the one on the Laura) to clear the wires and solder on the pads. If you're already cutting 2 holes, it's not much harder to cut 4.


I just received my Fraen reflectors, LED/20mm star, and my driver the past couple days. With some careful soldering, I don't believe I will need to clear my reflector for the wire, solder, or pads. I'm thinking I'll even be able to screw my star in place too :thumbsup:

El34 - with that insert I have shown below in the print below, I have found that we can use the same existing hole (but drilled out since it is a tapped hole) in the Marwi new style body with some thermal grease. Drill and tap a hole, for the 3mm screw, in the side of the insert (on the LED cup side). When everything gets assembled back together, the screw that used to hold only the rear switch cap in place will now also hold the LED w/star, the insert, and the driver in place. The reflector can have a .5mm - 1.0mm gap between the rear of the reflector and the face of the 20mm star to help keep the plastic reflector from absorbing any heat from the 20mm star. Bear in mind that this is all on "paper" but if my measurements are good, this should work "fine as froghair". I will be making my inserts within the week. I will post up how it works out. I don't have my 18650 cells or charger yet (coming from DX) so I won't be able to check out how the XML works with these reflectors


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## El34 (Jan 11, 2009)

That's cool, can't wait to see how your design works out.
Keep the pic's coming

I created a new post, instead of hijacking the thread here, on my Marwi Bullet housing slug test and the 8xAMC7135 boards.

Hoping to get some more info on those 8xAMC7135 multi mode boards
http://forums.mtbr.com/lights-diy-do-yourself/2800ma-amc7135-multi-mode-driver-boards-745871.html


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## mntn-biker (Sep 12, 2010)

El34 said:


> That's cool, can't wait to see how your design works out.
> Keep the pic's coming
> 
> I created a new post, instead of hijacking the thread here, on my Marwi Bullet housing slug test and the 8xAMC7135 boards.
> ...


I think I have overstayed my welcome on this thread accidentally/inadvertently hijacked this thread and I will be starting my own thread too once I have my inserts made.


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## El34 (Jan 11, 2009)

That's a good idea.


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## mntn-biker (Sep 12, 2010)

Sorry for hijacking your thread.

I have started my Marwi light build thread here


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## Uzzi_PA (Dec 15, 2009)

It's alright, I'm glad we could help get your light started. My project is pretty much at a conclusion anyways. Plus, there is a ton of good info on here now!


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