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  1. #26
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    Quote Originally Posted by Vancbiker View Post
    The best performance comes when the center pad is directly soldered to a copper heatsink.
    I use copper heatsinks and am wondering how to attach a bare emitter directly to these copper heatsink! How do you electrically insulate the 2 contacts on the underside of the emitter?

  2. #27
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    Quote Originally Posted by roxtar View Post
    IOW, no benefit to me whatsoever.
    Not unless you're messy with the solder paste and have a habit of licking your fingers.

  3. #28
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    Quote Originally Posted by plugp7 View Post
    I use copper heatsinks and am wondering how to attach a bare emitter directly to these copper heatsink! How do you electrically insulate the 2 contacts on the underside of the emitter?
    Easiest way would be to get in on the group buy Matt linked in this thread...

    Sinkpad copper XM-L/ XP-G 20mm stars GB on BLF

    Otherwise do it like Troutie did in the second post in this thread.

  4. #29
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    Quote Originally Posted by plugp7 View Post
    I use copper heatsinks and am wondering how to attach a bare emitter directly to these copper heatsink! How do you electrically insulate the 2 contacts on the underside of the emitter?
    most of the ones I've seen either mount it on a high enough pedestal that the + and - contacts hang in free air and leave space for the wires to be soldered OR grind off those pads and solder to the contact points on the top of the LED. You could even do a hybrid - grind off/ high mount one and solder the other one to the heatsink, using it as an electrical path.

    It'd be easier to buy one of those stars though PM Nitro direct as the group buy is closed.

  5. #30
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    Quote Originally Posted by plugp7 View Post
    I use copper heatsinks and am wondering how to attach a bare emitter directly to these copper heatsink! How do you electrically insulate the 2 contacts on the underside of the emitter?
    I made a PCB with pads that matched the 2 electrical contacts on the outer edge of the LED and a cutout the exact size of the thermal pad in the middle of the LED. Then I machined the copper heatsink with a raised area the exact height and size of the cutout in the PCB. Slipped the PCB over the post on the heat sink and then reflowed the LED to both the heatsink and PCB at the same time.

    In theory this could be even better than the solid copper mcpcbs because you can eliminate the joint between the mcpcb and the case if you're willing to have an all copper or brass case. There was an improvement in performance, but it wasn't dramatic in terms of perceived light level. I ended up deciding the improvement wasn't dramatic enough to justify all the extra work compared to a well designed normal mcpcb and case. But that's somewhat personal preference.

  6. #31
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    I've seen that before - looks really cool, but very fiddly. I saw a really neat twist on that on BLF recently. Instead of machining matching posts on the heatsink, the poster mounted the 4-up PCB and drilled through the centre pads of the PCB into the copper heatsink, then pressed and soldered matching copper rod into the holes. The rod was then cut down to the right height so that it was level with the top of the PCB.

    Not as good as machining the posts, as there's another part metal/ part solder interface, but easier and probably better than copper PCBs. I thought it was pretty neat.

  7. #32
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    I just read this thread on BLF - thoguht I would cross post it here:

    Match's Mods: Emitter to Copper Reflow in a 1C mag mod (How To) | BudgetLightForum.com

    If you read it - notice that this beamshot was done DURING THE FREAKIN DAY!!!


  8. #33
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    just showing off

    got a bunch of Xx-x2 LEDs, some copper sink pad stars and a tube of solder paste (which rocks)


    into


    XM-L2 on sinkpad and XP-E/G2 parallel triple is going to Ofroad'bent, hopefully he'll be able to give us some feedback when they're done!

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