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Thread: 1st build started today Quin SST-50

  1. #1

    Default 1st build started today Quin SST-50

    Not sure how this will turn out--going for mass lumens, with an attempt at handling the heat. I'm not concerned with practical use, size, or weight. I'm using 2" x 4" flat aluminum bar and turning it to build the head. The head alone will be almost 4" (diameter) x 6" (length) with imbedded copper cores under each LED. I will press in a 5/8" x 2 inch copper core into each hole in the head, then solder each LED directly to the copper heatsinks. I will cut fins in to create as much surface area as possible.

    Any ideas on how long this will handle the heat of almost 100W?

    Well, someday I'll get to post pics.

  2. #2

    Default Re: 1st build started today Quin SST-50

    I have read the rules and FAQs but cannot seem to find the post count required to attach an image. Can someone tell me how to obtain posting attachment privileges? Thanks.

  3. #3

    Default Re: 1st build started today Quin SST-50

    Hopefully I have figured out the image thing

    Here's some starting photos: 1.5 inch X 4 inch aluminum bar turned to 100mm X 37mm


    Layout with reflectors


    First holes bored. Layout done with manual protractor. They were off by more than 0.1 inches in various directions. The copper bar will be cut for heat dissipation.


    Since I have no rotary table or indexing head, I created this simple jig for more precision in boring holes for copper heatsinks.

    Now they are off by less than 4 thousandths in any direction.


    Copper bar cut to be turned and pressed into holes.


    Press 1 & 2 went well, #3 was a couple thou larger and the soft copper expanded, got sideways before I noticed.


    Should have used a sleeve--about 1/2 inch short of full press

  4. #4

    Default Re: 1st build started today Quin SST-50

    My plan is 5 SST-50s on this massive heatsink driven by a H6Flex at 5 amps. Practicality is not a consideration, so I'm not worried about size. I'll keep adding aluminum block with fins until it the heat can be fully dissipated. Any initial thoughts/comments/suggestions from the pros on this forum?

  5. #5

    Default Re: 1st build started today Quin SST-50

    Wow! Thats going to be one massive head. Is this a flashlight powered by batteries?

  6. #6

    Default Re: 1st build started today Quin SST-50

    Looks good so far but I hate to say it you will not gain anything really measurable going with copper inserts. I made 2 complete heatsinks one out of aluminum the other from solid copper. The copper heatsink at the end of my testing kept the LED's about 10 degrees (F) cooler.

    Mac
    www.macscustoms.com
    *Note* Shipping Insurance must be requested.

  7. #7

    Default Re: 1st build started today Quin SST-50

    Not sure how I'll power it away from the bench. I have a variable 30V/10A power supply to test with. With the H6Flex, I'll probably have to create a S/P battery combination to get any runtime at all with 18650s, right? (I have quite a few of these, no experience with many others used on builds I've seen in the forums.) I suspect I'll have to move up to higher capacity batteries, possibly hi drain/hi capacity RC batteries if I can get the head to produce the output I'm hoping for. (Before anyone says it, I realize I'm approaching this backwards

    One of the main reasons I am using copper is that I wanted to solder the LEDs directly to the heatsink. I don't have star LEDs. I'm already regretting that decision--too much work for very little gain as you pointed out.

  8. #8

    Default Re: 1st build started today Quin SST-50

    Quote Originally Posted by Curdog92 View Post
    One of the main reasons I am using copper is that I wanted to solder the LEDs directly to the heatsink. I don't have star LEDs. I'm already regretting that decision--too much work for very little gain as you pointed out.
    You would of had to solder the LED's to the Copper posts before pressing them into the aluminum heatsink as it would be really hard to do it now. I have some extra left over SST-50 bare star boards if you want 6 of them PM me your address. I think I have that many left

    Mac
    www.macscustoms.com
    *Note* Shipping Insurance must be requested.

  9. #9

    Default Re: 1st build started today Quin SST-50

    Thanks for the offer, but before I take you up on it, let me get your advice on my plan. I had intended to mill a 6.5x5.6mm rectangular platform on each copper core. (Similar to what was done in this thread http://www.candlepowerforums.com/vb/...-at-5A-by-H6CC, but my platforms would be sized to the LED die, versus a round platform as wquiles did.) Since this head is massive, a heat station or heat pen is not practical, so I was hoping to use solder paste and mount the LED dies in an oven much like many DIYers use ovens/solder paste to remount SMDs. My big question is this: can a SST-50 LED withstand 475 F in an oven? (I had planned to test this theory with a cheaper LED.)

  10. #10
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    Default Re: 1st build started today Quin SST-50

    Quote Originally Posted by Curdog92 View Post
    . . . . My big question is this: can a SST-50 LED withstand 475 F in an oven? . . . .
    For a reliable life, the ONLY data you can trust is from the manufacturers datasheet.

    Heating time = 2.75 to 3.5 minutes

    Max Temperature = 217 deg C for 30 to 60 sec

    Cooldown rate = LESS THAN 4 degC per second

    Cooldown time 30 to 60 seconds

  11. #11
    Flashaholic* lucca brassi's Avatar
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    Default Re: 1st build started today Quin SST-50

    For a reliable life, the ONLY data you can trust is from the manufacturers datasheet.

    Heating time = 2.75 to 3.5 minutes

    Max Temperature = 217 deg C for 30 to 60 sec

    Cooldown rate = LESS THAN 4 degC per second

    Cooldown time 30 to 60 seconds

    but this is very strict temperature protocol for reflow soldering not for kitchen owen ! http://www.luminus.com/products/data..._Datasheet.pdf from picture on page 15

  12. #12
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    Default Re: 1st build started today Quin SST-50

    Quote Originally Posted by lucca brassi View Post
    but this is very strict temperature protocol for reflow soldering
    .... and that is exactly what he is planning to do.

  13. #13

    Default Re: 1st build started today Quin SST-50

    Curdog92, this thread might interest you.

  14. #14

    Default Re: 1st build started today Quin SST-50

    Thanks for the input. Yes, I have followed quite a few of these massive builds, and they were my inspiration. I was a little off on my C to F conversion...I bought Zephyrtronics solder paste which reflows at 217-219C, same spec as the LED temp. Reflowing a SMD on a PCB is easy in an oven. Just cover the pad with solder paste, place the SMD on the pad/paste, and watch until the solder liquifies/SMD settles into place, and remove from oven. But with this massive head/heatsink, I fear there will be a huge time differential between the heatsink and LED reaching the required temperature. My plan is to preheat the head. I'll place it in the oven, and time how long it takes to get up to the required temp. Once I know the required time, then I can complete the task in one quick step. For example, if it takes the head 10 minutes to get to 217 C, then I know that at 9 minutes, I have to open the oven, place the LEDs with tweezers, wait for them to settle, then remove from oven.

    Or, if I knew the LED could withstand the temp longer than specs on the data sheet, I would set it all up while cool, "cook until done" and remove. I guess I should have fully explained my question. Thanks for the input.

  15. #15

    Default Re: 1st build started today Quin SST-50

    Maybe you could try it in a cast iron frying pan on the range. The leds shouldn't see as much heat until seated.

  16. #16

    Default Re: 1st build started today Quin SST-50

    That's a great idea! I had not thought of that...Thanks.

    All 5 copper cores now pressed:



    This weekend I'll mill them down to to the size of the LED die and let you know if the frying pan idea works!

  17. #17
    Flashaholic* lucca brassi's Avatar
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    Default Re: 1st build started today Quin SST-50

    I can said that massive heatsink is very bad idea , heatsink must be light and have big surface and material from high thermal conuctivity .

    To full use of the thermal transport routes (and lower common mass ) temperature should be spread form the thick base with placed leds to the most remote section of which is the thinnest .

    The best shape for handheld torch inserts is H shape .

    To optimize such big beast is very good idea to thermal isolate leds between them not to cumulate heat in the heatsink mass...



    white area is thermal insulator in black air gap
    Last edited by lucca brassi; 01-21-2012 at 01:20 AM.

  18. #18

    Default Re: 1st build started today Quin SST-50

    A propane torch may also help in the installation. You could try heating the side of the heat sink inline with the copper pedestal while in the pan at a lower temp. To bring just the pedestal where your installing the led up to temp. Then move to the next one once reflowed. This may keep the heat down on the leds you have installed while trying to install the rest. This is all just suggestion's. I do know that aluminum will spread heat pretty evenly and quickly. Wish you luck Curdog92.
    Last edited by moderator007; 01-19-2012 at 11:54 PM.

  19. #19
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    Default Re: 1st build started today Quin SST-50

    Wow that looks nice! I would add a lot of fins to the heatsink. A massive heatsink alone wont keep it cool for long.

  20. #20

    Default Re: 1st build started today Quin SST-50

    Thanks. I've got a plan for fins and cooling...remember I expect the head alone to be about 6 x 4 inches when done. (If that's not enough, I'll add more.) Instead of leaving the round copper cores protruding, and milling them to 5.6 x 6.5 mm to create LED solder pads, I decided to create a smooth copper/aluminum surface, and mill grooves to create the pads. See photo--haven't milled grooves yet.


    I do have a question. What guage wire should be used to wire the LEDs up in series? And then, let's say I have to go 4 inches to the H6flex, what guage?

  21. #21

    Default Re: 1st build started today Quin SST-50

    The current determines wire size not voltage. In series you have a high voltage with what ever your estimated drive current will be. I am assuming your going to run at 5amps. 22 AWG would probably work fine but 20 AWG or below would be better. The bigger the wire the less resistance. If you can get some silicone high strand count wire that would be best. You can find it at RC hobby shops or online sold by the foot.

  22. #22

    Default Re: 1st build started today Quin SST-50

    Made a little progress on my project...here's a few pics.







    First thought was to mount LEDs on pads, then solder wiring to the underside, then encase the wiring in JB Weld. After further thought, I now plan to mill out a groove in the JB Weld to create a solid copper wire inlay so that the LED will mount just like it would as a SMD. If it works out as planned, it should be a very clean install for the LEDs.

  23. #23
    *Flashaholic* wquiles's Avatar
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    Default Re: 1st build started today Quin SST-50

    Great photos - looking forward to seeing more of the project

    Will
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  24. #24

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    This project is looking great. Thanks for sharing!

    Sent from my DROID BIONIC using Tapatalk

  25. #25

    Default Re: 1st build started today Quin SST-50

    Nice work, the JB weld should work out great. Ive done comparative testing and had stars mounted to heatsinks with JB weld, and it handled reflowing just fine. Cant wait to see the copper inlaid and turned down.
    As big and thermally massive as that heatsink is, I'd reflow the LEDs on a stovetop. Add a temperature sensor (the infrared laser ones wont be accurate with bare aluminum!), And if youre using solder paste, apply your paste, heat the whole thing to ~100-115 C, place your LEDs carefully, and turn the stove up and watch closely. Once the solder starts melting, turn off the stove since the temp will keep rising a bit as the heat on the bottom makes it way to the top. let it cool enough for the solder to solidify, then move it to another burner to cool fully (if you have an electric stove. If you have a gas one, I'd imagine its fine just letting it sit where it was)

    Dont quench it in water, or cool it very quick, as the ramp down rate is just as important(if not more important) as the ramp up rate.

  26. #26
    Flashaholic Hoop's Avatar
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    Default Re: 1st build started today Quin SST-50

    Is that a cnc mill? If not, how did you machine the circle without a rotary device?

    Press fits should generally be around a few tenths to a half thousandth to avoid galling and bent pins. (pin should be .0002 to .0005 larger than the mating hole)

  27. #27
    *Flashaholic* easilyled's Avatar
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    Default Re: 1st build started today Quin SST-50

    Exciting project. You have enviable skills.

    I'm just wondering why you choose to use SST-50s instead of XM-Ls? XM-Ls are significantly more efficient than SST-50s and produce less heat. Even though you can drive SST-50s harder you get as much light output from driving an XM-L at 3.0A as you do from driving an SST-50 at 5.0A and at that drive the SST-50 consumes far more power and produces far more heat.
    Change is inevitable, except from a vending machine

  28. #28

    Default Re: 1st build started today Quin SST-50

    Thanks for the comments. I tested the stovetop method tonight with success with a few non LED SMDs--worked fine, although it was on a much smaller scale. I am still testing different methods of creating the copper traces--having trouble with just about everything I tried. I tried solid copper wire milled to 0.7mm, pressed copper wire, even milled copper block. But the best results have come from cutting a 2 mm cross section of 1 inch copper tubing, then cutting the circular piece, flattening it out, and then shaping it to fit from LED to LED. The wall thickness is 0.8mm so I essentially end up with a rectangular wire (2mm X 0.8mm) that is easily bent and shaped into place and will sit upright once I refill the groove with JB Weld.

    I am using a non-CNC, 1988 model RF 31 mill I picked up for $500 a few years back. It has tons of run-out, and several hundredths of slop/backlash on every axis. It's very hard to get any precision out of it--tons of compensation required while working with it. At the same time I'm working on the flashlight, I am slowly restoring the mill.

    I created a little jig with a pointer (that can be seen in the pictures clamped to the mill table) and rotate the head by hand. While I realize its not safe to mill something being rotated by hand, it is aluminum, I'm using a small bit, and I'm taking very small cuts on each pass.

    I divided the head into 5 parts using a compass/protractor initially and was off by large amounts--several hundredths. I finally achieved reasonable accuracy using simple geometry to calculate the distance between the 5 points on the star, then used a digital caliper with the distance locked to scribe the 5 marks around the perimeter. The head is rotated on the jig using the pointer to get my 5 sides.

    SST-50s and reflectors cost $50. I thought that was a great package deal.

    This is more of a learning process than anything else for me.
    Last edited by Curdog92; 01-31-2012 at 12:12 AM.

  29. #29
    Flashaholic Hoop's Avatar
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    Default Re: 1st build started today Quin SST-50

    Good choice on the SST-50 imo. XML's have nasty green tint that people fail to mention. SST's are quality in comparison.

  30. #30

    Default Re: 1st build started today Quin SST-50

    Little more progress... I gave up on creating a solid copper connection from one LED to the next in one fell swoop. Instead, I decided to create individual pads that can be placed more precisely. Once the pads secured in place with JB Weld, I'll solder a wire link from pad to pad, then encase all the copper in JB Weld. I milled some 10 ga copper wire into what I'll call "angle iron" type copper bar. The grooves cut into the heat sink are 2 mm deep, and 4 mm wide. The copper wire was milled to 2.5 x 2.5mm, then milled down to create the 0.7mm x 6.5mm LED +/- pads.







    Way too much work going into this...but it's a fun learning process. I'm bound and determined to mount the LEDs as SMDs...would probably have finished by now had I went with stars

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