Help with my first mod - Mag 3D

Hi all,

Well, I've had a Mag 3D sitting in the closet ever since I bought my first SF. I'm going on a camping trip soon and thought a 1W LS mod would be perfect for it /ubbthreads/images/graemlins/cool.gif

Just a couple questions...

- Where's the best place to buy a LS, and should I buy a HD, LD, or SE for the stock Mag reflector?

- In guides that I've found, people have shown the heatsink with LED attached mounted about 1/2" below the top of the body. I would think that you would want the LED to protrude as far into the reflector as possible???

- I've also seen flat heat sinks and sinks with small pedestals, which should I choose and where to get them?

- Finally, I've see all different sorts of resistor values thrown around, but what value should I go with and what power rating?

- Last, what about a 5W LS? Can I do it with this light?

Thanks for the help. Hopefully my first mod will be a successful one!

Q1: You can buy LS's from anlighten.com/shop, elektrolumens.com or ???? Want light close to you - SE, want throw - HD, LD is sorta in between SE and HD (Someone please correct me)

Q2: It depends how much you turn the head piece down into the body... hence the beam pattern. 12-13mm down is pretty much near the limit. THe reflector will need to be cut pretty close at the 'stalk' (btwn curve and straight bits) for this much travel down the barrel.

Q3: Disc or pedestal? Hmmm... either one will work. Make sure it is heatsinked properly. Stay tuned for more on this one.

Q4: If you use the 3 x 1.5 batts, get something like a 2R2 for a ~40% overdrive. Less resistance for a brighter light. Q3 is very important.

Q5: 5W can be used very successfully. It will be bright! See this recent thread. Q3 is extremely important when doing a 5W mod. Otherwise you will fry your $30 LS 'investment'. You would want something like a 2R7 (3R3 for safety ?) for rated drive. But this will depend on the bin of the LS you get. The above calc is based on a U bin. Getting binned LS is difficult. See Q1 above. Getting good binned LS is a lot more difficult. Sometimes, it is better to get a lower binned version than to try your luck with unbinned ones.

Hope this will get you started. /ubbthreads/images/graemlins/smile.gif

Thanks, hotbeam. Can you decipher the 2R2 and Q3 for a n00b? /ubbthreads/images/graemlins/smile.gif

Hey chief, 2R2 is a 2.2 ohm resistor. Q3 refers to your question regarding heatsinking, either option will do the trick. The question is how efficient you want the heat transfer to be?

I don't use any resistors, and I use a dead flat .125 aluminum heatsink set .240 down from the top edge of the body. I grind the "camming tube" off of the original Mag relector just to the point where the line between the tube and wall starts to disappear.



I do it this way because I like the "tightest throwing" beam to be when the head is screwed all the way on.

Thanks, Slick. Useful info there.

Slick, I forgot to ask, what kind of luxeon do you use? Are those measurments for the star or the bare emitter?

Chief - I use bare emitters whether they are Batwing, HD or SE.. Also when I'm doing my set up, I use an original Maglite lens that I've ground the center out of.. That way I can properly tighten everything down to secure the reflector, then because the bezel is open - (due to the cut-out lens) I can scribe a circular line around the circumference of where the reflector meets the heatsink. The "scratches" that you see outside of the scribed circle is where the reflector base tightens against the heatsink. Using that scribed circle as a reference, I can easily center the emitter and determine where to drill the holes for the leads to come through (they must be inside the scribed circle to not interfere with the reflector being able to touch the heatsink. Some modders use "pedestals" to raise the emitter, but I've found that to be unecessary using my technique..



Just so you know, you WILL have to remove the switch and prune the "nose" to permit the haetsink to sit that low in the body. Using a PR bulb base as a power pickup won't work doing it my way.. Besides, I feel that soldered connections are more reliable - especially when that connection sits underneath a pressed-in (and epoxied) heatsink.

hey...i like the pedastal! /ubbthreads/images/graemlins/grin.gif

actually, it's quite a bit easier too /ubbthreads/images/graemlins/grin.gif (not to mention it works with any mod...not just ones where the luxeon is inside the lip /ubbthreads/images/graemlins/grin.gif )

I like the pedestal too - but only if it's necessary.. The Brinkmann 2D needs one like this..

Note that the 2D Brinkmann host also needs the heatsink to be flush with the top edge of the body tube->


The only thing I've found a pedestal to do for a Mag mod - is permit it to focus into the "black hole" on both sides of optimal focus. /ubbthreads/images/graemlins/icon3.gif I build my lights so that the tightest focus of the beam occurs approximately 1 quarter turn before the bezel is totally tightened down. I like the bezels to be screwed on the light as far as possible since this improves the stability (less head wobble) and gives more uniform beam characteristics.

It also makes the light as short as possible too..

EDIT - BTW, I cut my heatsinks out with an air powered "body saw", then nearly finish them up using a belt sander. Final fitting is done using a fine cut mill file to a ~ 15-20lb press fit. Arctic Alunina thermal epoxy is used during the final assembly.

Slick, thanks for the follow up info. That's exactly what I needed to know. Now if I could only find a 1 watt LS /ubbthreads/images/graemlins/frown.gif

slick, i'm not entirely sure if you understood what i was talking about. if you look close at this picture, you will see a smaller post in the middle of the main post. this makes centering luxeons extremely easy.

Oh mamma those are sweet! Are you making and selling them, or just teasing???

http://elektrolumens.com/ sells the bare luxeon star, and has a bundle with a heat sink which fits a maglight. He also sells high power resistors.

thanks chief /ubbthreads/images/graemlins/grin.gif

well...i have made them for cpfers in the past, but i'm extremely busy right now, and as a result, they would be expensive /ubbthreads/images/graemlins/frown.gif around $25 /ubbthreads/images/graemlins/frown.gif

I have one of each of the Rothrandir heatsinks shown above (almost, but not quite, identical, I believe). I had them made when he was not so busy, and I got an amazing bargain on them, thanks Jim!

These heatsinks are great! /ubbthreads/images/graemlins/bowdown.gif Notice the huge amount of surface that makes contact with the flashlight body; awesome heat transfer (I have not done any formal testing of that, though).

So far I've used only the one without the lip.

I'm accustomed to the Mag focusing style where tightest focus is in the middle of the focus range, not one end. The defocus when the light source is further inside the reflector is different than when it's further out, and it can be preferable in some cases. The pedestal design allows this.

Jim,

The pedestal-within-a-pedestal, I found, was extremely helpful in centering the emitter, great idea! However... I very carefully centered the emitter using your guide, and then had trouble holding it still in place while the epoxy set. Might I suggest the following enhancement: Instead of a raised centering guide, how about a recessed well, exactly the diameter of a 5W emitter, perhaps 1-2 mm deep? that would mean that you could place the emitter in this well, and press it down for best adhesion, with no worry about it moving on you. 100% perfect centering guaranteed every time!

If you try this idea and it works out, maybe this gets me another bargain on one or two such heatinks? (the simpler, non-lip design would do). /ubbthreads/images/graemlins/grin.gif

Kill-O-zap.
what about the leads? your +lux leads cannot touch the heatsink or you might kill your lux instantly.
that is what happened to mine /ubbthreads/images/graemlins/frown.gif . Do PREVENT the base of the emitter and the - lead to touch the same metal when you tried to turn the lux on or you will short your lux and say bye bye to your $30 investment

Yes, I had thought of that. I thought though that if the well were only 1-2mm deep, that having the LS leads lifted UP away from the heatsink should be sufficient to prevent this. The leads need to be bent this way anyway to be sure they don't come into contact with the reflector, also. If just bending upwards is not sufficient, it might be necessary to cut out slots in the sides of the well, but I don't think that would be the case.

[ QUOTE ]
Rothrandir said:
slick, i'm not entirely sure if you understood what i was talking about. if you look close at this picture, you will see a smaller post in the middle of the main post. this makes centering luxeons extremely easy.



[/ QUOTE ]

Those are real nice heatsinks Roth.. /ubbthreads/images/graemlins/thumbsup.gif But as long as the Mag's reflector is ground as I described in an earlier post, a pedesatal only yeilds the "black hole" region of focus, which I do not prefer.

I make my heasinks from pieces of punched out 2inch diameter slugs. I use an original Lambda heatsink to scribe my cut line to the proper diameter. Cutting and grinding is the hard part - that takes 15 to 20 minutes.

I had a friend make one on a lathe and he couldn't churn them out fast enough for me to run out and buy a lathe (yet), and I build a fair amount of mods too.

So my heatsinks are basically free (material wise) outside of my investment of time.

You know, everytime I have the money to buy a lathe, I wind up buying more Luxeon emitters instead! someday tho.. /ubbthreads/images/graemlins/smile.gif

kill, i have tried that, but found that it is very hard to solder without shorting everything out, as shiftd has said.
do you build mods in an anti-gravity chamber where the luxeon floats away? /ubbthreads/images/graemlins/grin.gif
holding the luxeon shouldn't be necessary, just align and walk away. come back once it's dry /ubbthreads/images/graemlins/grin.gif

sorry slick...no black hole /ubbthreads/images/graemlins/grin.gif
the main part of the slug does not line up with the mag rim, it is below. it allows for easy focusing on either side of the perfect focal point /ubbthreads/images/graemlins/smile.gif (so yes...you can have a black hole...you just need rotate the head a bit... /ubbthreads/images/graemlins/grin.gif )

your method is faster than mine!!! /ubbthreads/images/graemlins/eek.gif