Direct bonding to copper: p60 triple nichia build + p60 XML build

Flashlight Modding and DIY Parts
15

Yea, I think a threaded pill will be better but a well fitted p60 drop-in should work relatively well.

The reason I want to add thermal mass is because it would also speed up moving heat to the host. I think all of this will allow for a longer period of time before the host to air heat movement is saturated. Although it still might not allow me to use high for a full battery, it would allow me to use it for longer and for the LEDs to not drop in lumen output as much (thermal sag). And if I use these lights on the lower level, the extra heatsinking will help a lot with keeping the LED output up.

16

I think, in your position, I’d get some of the copper sink-pads at 20mm made for the XM-L and reduce it’s dimension to 16mm, then reflow the emitter onto it which should be fairly easy as it’s designed for this emitter.

I am planning the same thing myself and have never done it before. My plan is to mount the sink-pad on a 1/2” aluminum bar using JBWeld, then use my cordless drill to turn the pad slowly while cutting it down with a grinding disc on my dremel tool. This should keep it perfectly round (or very near so) while keeping the emitter pad centered. Then cut the JBWeld off the backside of the pad and clean it up a bit with sandpaper. Laying the sandpaper on a glass surface, or formica, it’s easy to keep the part neat and flat when sanding. I also usually use a rotating pattern when doing this sanding, to ensure I don’t lean to one side…but still check it often during the process.

It’s my plan to use a 6” SS disc I have and put it on the burner element of a glass top stove. This will keep the element working properly and give me a good hot base to bring heat up in the copper sink-pad to reflow. I’ve seen some that recommend simply killing the heat when the reflow is accomplished and leaving it to cool naturally so as not to interfere with the joint or the emitter by moving it. I plan to relocate it to the glass stove-top though, to cool somewhat faster than that.

Like your plan to put copper in the core of the pill. Never have been able to understand why they use brass instead. Cost in that small of a part is offset by machining costs as far as I’m concerned, so add the extra buck or two to the finished light and call it efficient.

Will definately watch to see how you go about this build, the copper core in the pill really interests me.

17

I probably won’t be able to start this build for awhile as I am away for college and my tools are at home. I have to wait until May (2.5 months) to try this out. I’ll make a new thread once I start though to share what I build (and what I can’t if I fail :_( )

Will filing down those 20mm Stars to 16mm work? As in are the contacts close in enough that it would be ok? I might end up using that instead of building my own star. This is if my initial plan to direct bond the LED to a large chunk of copper fails. I’m also hopign the 16mm sinkpads are out by the time I start

18

I’m very impressed with Fred’s work, to say the least. Those threads, man, just incredible! He made a pill fob for my wife from the remaining part of the Ti bar I sent him. I’ve got that in hand and I can testify you will not find a smoother operating thread anywhere, and this is the fabled hard-to-thread Titanium! Same .5mm thread pitch, and smooth as hot butter on oiled Teflon.

This light will be worn on a Ti curb chain around my neck. :slight_smile: The piece-de-resistance of my flashaholism period. :slight_smile:

19

I'll try to make this short.

DBC, thats a nice little thingy. But you cant compare that to the usual C8 threads.

Pulsar, metal to metal is far better than thermal paste. But I'm sure you know that. It helps of course, but not much.

skyrider, if you get a direct to copper or brass bond of the center heat pad and wrap the dropin tightly, you are good to go. 3A is easy if you always hold the light with your whole hand. Human blood works very well as a heatsink.

matt, you have some good points but some are not so good. First of all: more thermal mass does not mean that the light will cool down slower when powered for the same time with the same power as one with less thermal mass. Thats just wrong. Adding mass does not change the ability of the body to dissipate heat.

Of course you need thermal mass for short bursts of high power. But not mainly because the light will get too hot to hold (you could use gloves) but because you move the point where thermal sag happens. Thats the main reason for copper bonding: more light. Who cares about heat, turbo mode has the name for a reason.

Now for your argument about threads. The pill doesnt rattle when screwed in, thats right. But not because the threads are so tight (you wouldnt be able to screw the pill in by hand so easily if that was true) but because once you fully screwed in the pill and screw it tightly, there is pressure on the threads. A little less than half the area of the threads will be in contact at that point. If you dont believe me, take a threaded rod and two nuts. You can screw them on very easy, now screw them tightly against each other. You wont be able to move them by without tools anymore now.

Ok, that wasnt short. Sue me. ;)

/edit: DBC, to make Sinkpads round, you could solder some thick copper wire to the back. Manufacturers use brass because copper is a PITA to work with, that would boost machining costs. Also, if you reflow, let the emitter cool down slowly. They dont like thermal shocks.

skyrider, its no problem to sand down stars. If the electrical pads come too close to the edge, file them off (I use a dremel for that).

20

Keep an eye on Nitro’s thread, he’s trying to get Sink-Pad 16mm’s made.

Vestureofblood is selling the 20mm copper stars now, in XP-G and XM-L formats.

Fred turned a 20mm star down to 10mm for my build, so anything is possible!! :slight_smile:

21

Oh, I forgot some nice data:

Taken from here: http://www.taschenlampen-forum.de/modding/13515-bastis-bastelbude-13.html#post296083

Testing of a copper star on Alu, Cu and Ms (brass) heatsinks. The material doesnt matter all that much at all..

22

Can you post the pictures here? I don’t have an account there.

Are these direct bonded copper stars?

23

Yes, copper bonded.

/edit: I fixed it.

24

I must not have been very clear. Obviously, more thermal mass will not take longer to cool down if it receives the same thermal input as an object of a lower thermal mass if they have the same surface area. That’s pretty pretty obvious. However, that’s not what I’m talking about. I’m talking what happens once the object has reached steady state equilibrium (ie. it’s temperature has stabilised), which obviously takes longer with objects of greater thermal mass as they can absorb more thermal energry. However, because they’ve absorbed more thermal energy, they have more thermal energy to dissipate once the heat source is removed. Like filling a bath vs. filling a sink. A bath holds more water, so it takes longer to fill up, but because it holds more water it takes longer to empty (the plug hole being the surface area of the housing in this case :laughing:. Pretty simple stuff.

As for thread surface area. Where is the force coming from to mate the metal surfaces together in your P60 drop in/ housing interface? How much metal is being forced into direct contact? Is the force perpendicular to the two surfaces or in shear? Unless your P60 drop in has an interference fit into your torch body (without any thermal gunk, wrap etc), such that you have to press it in with a vise or use differential expansion, then there is simply no way that it has more metal to metal contact than a threaded pill of the same depth. It is unlikely that it has much by way of direct metal to metal contact at all, perhaps a thin ring where the base of the pill hits the body tube or the reflector touches the bezel. The P60 format, AFAIK, was designed for filament lights that project most of their waste heat out the front of the light, not through the housing. If you wanted to design a light format from scratch to use with LEDs, there’s no way you’d choose a loose fit spring loaded format, you’d choose a threaded pill of a standard pitch.

25

Sorry Nightcrawl, but I never said anything about a C8 or it’s threads, and neither did the OP. My comments and the added pictures were to enforce what Matt was saying, to give ideas to skyrider as to how he might accomplish his goal. Not trying to start an argument, and you obviously know far more than I do about this subject, but to classify the incredible machining accomplishment of my lights head as “thingy” is pretty downgrading and not really called for in the least nor even vaguely appreciated.

Was just trying to help the OP with his ideas, which is what I thought this forum was all about.

And now, on to the regularly scheduled program.

Skyrider, tightly wrapping your P60 drop-in will most likely give you the result you’re looking for, without added copper mass in the pill. Going to that length would be more suitable for a larger light running multiple XM-L’s at higher amperage, with an accompanying larger head with better heat dispersal capabilities. That’s pretty much been aluded to here already. I have a triple Nichia 219 in a Solarforce L2P and it does very well, the entire body warms up but I haven’t run it for extended periods as I know it’s not great for the emitters and, as yet, have not needed this particular light for long illumination times. I have bigger lights for that, when that time comes. That being said, this Tri 219 is in a copper P60 drop in from EDC+ so it provides a larger mass for heat dispersal and the host does well removing that heat from the copper, with it being wrapped of course.

Good luck with your endeavor, still look forward to seeing how you go about your design.

26

matt, indeed, your explanation clarified what you meant. :)

My tightly wrapped P60 dropins have good heat transfer. They get warm as fast as my UF980L with a screw-in pill design. The force comes from a very tight fit..?^^
P60 has its disadvantages, but they are interchangeable. The C8 isnt, there are so many manufacturers and they dont all use the same threading..

DBC, you obviously didnt read matts post two posts over mine. Thats where he mentioned the C8 and thats what I answered to. Next you show some great threads (which have nothing to do with most crappy C8 threads at which my post was directed) and tell me there wont be much air inbetween, which is pretty obvious.

Thingy was not meant offensive, its just a neat small light. Neat thingy is a compliment in German. ;) I hope we will see a thread about your neat thingy once its done.

The EDC+ dropin is also a neat thing but no challenge for a P60 host. 2A is safe even for very long runs.

27

I did indeed read the initial reply from Matt, and understood your explanation as the why concerning C8 threads. Being fairly new to the forum, I have yet to master following multiple conversations within a thread and usually try to keep the OP in mind. Doesn’t help getting old and forgetful.

Y’all will definately see more on my “lil thingy” when it’s done. Looking for ~300 lumens or more from this pinky sized little dynamo, we’ll see how that works out.

And yes, the EDC+ is a bit on the conservative side. For some reason my DMM won’t get a Hi reading at the tail, but Med is 1A and Lo is .03A. Nice build, like what they did with the copper body and silver plating, very useful drop-in for some down-and-dirty illumination during macro photography. I plan on getting one that will be quite different, already have the host built, that Matt is working on over in Australia. I’m thinking it won’t be quite so tame, as he advised me to upgrade the switch in my host so it wouldn’t be melted down with his drop-in :wink:

Skyrider, are you looking for more output than you’re seeing in readily available drop-ins, or are you primarily interested in the DIY project?

28

I think the interchangeability is its biggest advantage, which also leads to another big advantage - the relatively loose tolerances manufacturers can get away with and it still manages to work. Given the difficulty manufacturers seem to have just getting the bore size right, I shudder to think what the outcome would be when you throw threading in there. I guess in the real world, ease/ cost of manufacture trumps all :slight_smile:

29

DBC, yes, multiple conversations in one thread can be a downside in such a low-regulated forum like this. But I really enjoy it. Thats why I usually start my posts with the name of the one I'm adressing my post (or parts of it) at. :)

matt, yep, definitely. Even Solarforce hosts have different head IDs..

30

You stated in your first post that ” I will solder 3 very small pieces of rectangular pads on top for bonding the LEDs.” That won’t work, will it? The pads have to be isolated from the heatsink or they’d be a direct short. Soldering them in place isn’t an option, is it? Am I missing something here?

Edit: I see it now. Soldering a pad for the center of the emitter to be bonded directly through copper to the copper heatsink will raise the electrical connections and prevent the contact that I thought would short them out. Will you, then, connect the wires at the top of the emitter?

31

Solarforce is not consistent?

<—hand over mouth, frantically checking the 3 in front of me while worrying about the P1d the wife has. :open_mouth:

32

I have an L2P and an L2T and they are off by a few tenths of a mm. Also, the inside of the L2T is not as smooth as the inside of the L2P.

The Nichia does not have solder pads on top btw. So if you want to raise it, soldering wires will be hard. I would rather use three 10mm stars. That would work.

33

Skyrider, I just got 20mm SinkPads and I’ll be attempting to turn some of them down. Will let you know how that goes. You’re looking for a single XM-L, correct? My main project here is an XP-G so I may just attempt the XM-L to 16mm and get a feel for it, before going for 10mm on the xp-g.

If I’m successful in turning down this XM-L copper star down to 16mm, you want it? I got 5 boards in XM-L and 10 for Nichia, XP-G.

Nightcrawl, anything I should know before I attempt resizing these?

Will be taking some pics first, I’ll post em a bit later.

34

Yes, copper is pretty hard to grind down compared to Aluminium. Dont let it get too hot.. and when you are done, check for connection between the center pad and the positive and negative pads with a DMM.