I was thinking to use 2 alluminium L profiles (front of each -other) and three straight alluminium panels to carry the cobs 2 on the outside panels and one in the middle... smth similar to bizfactory's frame ( hope you are ok biz with me sharing this.)What will you be using to spread them out? Or will they hang from the ceiling individually?
yes indeed, it actually inspired my project along with some other great ideas in this forum.no probs! means I did an okay job!
Yup, what I mean is can you use the Kapton tape to hold the COB on just as if it were masking tape. No screws no drilling, etc. I have been trolling around and I see lots of photos posted where it appears that is all that's holding them on. (that and whatever adhesion the heatsink paste offers). I heard some of the heatsink paste becomes like a glue.While we wait for his answers, here is everything about Kapton Tape. I have been thinking about it, too.
You get some elongation as the temp. rises but not much.
http://www.dupont.com/content/dam/assets/products-and-services/membranes-films/assets/DEC-Kapton-summary-of-properties.pdf
Some of the properties such as tensile strength will degrade to zero over time, in heat. It doesn't like UV exposure, or water.
But, I am not sure what you mean. Just use it like masking tape? Or is it double sided between the COB and the sink? The problem is not attachment, you know?
The problem is to create a thermally efficient bond between the junction and the heat sink. Not an easy problem. To see the problem you need imagination as it happens on the microscopic level.
Supra when through enormous work to polish his heat sink. Why? He made the surface as gap free smooth as possible. It shines, it reflects, it looks like 4 wires when there are only 2.
I saw a prototype of our latest processor yesterday. It is polished as fine as a mirror in a telescope. Why? Same thing. It is what the polished side the heat sink clamps to.
So, heat can only transfer directly molecule to molecule. If a molecule of aluminum is in DIRECT contact with molecule of COB bottom surface, heat will flow easiest. But, if there is the most sub-microscopic gap in smoothness there, it is an AIR GAP. <GASP> Now the heat has to go through molecules of air first.
This is why use expensive silver based gap filling compounds, because the gaps we are talking about are not visible to the eye.
So, can Kapton apply enough pressure to keep the gap filler happy? That's the main question.
That's why we use screws, polish work, and gap filler.
I am reading in the design guide you are not suppose to use screws, EVER.Yup, what I mean is can you use the Kapton tape to hold the COB on just as if it were masking tape. No screws no drilling, etc. I have been trolling around and I see lots of photos posted where it appears that is all that's holding them on. (that and whatever adhesion the heatsink paste offers). I heard some of the heatsink paste becomes like a glue.
Well, gald you mentioned that, I did just see Luxeon Thermally Conductive Adhesive Tape for High Power LEDs, but I can't recall seeing anyone use it here, so I thought it must not be good. There is a Youtube of the guy applying it and it looks as easy as sticking one side on the heatsink and then pressing the LED on. It is double-sided tape that attaches the LED as well as acts as the thermal bond.There is gap tape, also. It is a thin membrane with double sided adhesive. There are kinds that will melt at the first temp cycle only. After cooling it won't melt again.
So, good gap filler and attachment.
Seriously, that is no way to look at DIY as far as I am concerned. There is no way for anyone to be completely knowledgeable with all the new tech coming on line.Well, gald you mentioned that, I did just see Luxeon Thermally Conductive Adheshive Tape for High Power LEDs, but I can't recall seeing anyone use it here, so I thought it must not be good. There is a Youtube of the guy applying it and it looks as easy as sticking one side on the heatsink and then pressing the LED on. It is double-sided tape that attaches the LED as well as act as the paste.
http://www.luxeonstar.com/thermally-conductive-adhesive-tape-for-high-power-leds
Using latex gloves for those greasy fingers is highly recommended.Well, gald you mentioned that, I did just see Luxeon Thermally Conductive Adheshive Tape for High Power LEDs, but I can't recall seeing anyone use it here, so I thought it must not be good. There is a Youtube of the guy applying it and it looks as easy as sticking one side on the heatsink and then pressing the LED on. It is double-sided tape that attaches the LED as well as act as the paste.
http://www.luxeonstar.com/thermally-conductive-adhesive-tape-for-high-power-leds
See? I think the Kapton will not last in the Grow room environment.I used Arctic Silver ADHESIVE, the stuff stick like glue, worked great. Also used thermal paste with kapton tape, but the COB feel off. Was glad I used adhesive.
Well, there is. But, is the Cree polished like a mirror on the back? You need both these surfaces incredibly smooth to make a mating surface with very tight tolerance.Oh and btw, Supra doesn't polish anymore, no benefit for the effort expended was his conclusion.
I would bet low thermal impedance, like the the rest of the "layer" types....I have looked at a few....even bought some from Digikey in the past, the 3m mounting tape....but all have shitty impedance compared to paste, which sucks, because applying paste manually imho, is one of the variables that needs to be eliminated....Well, gald you mentioned that, I did just see Luxeon Thermally Conductive Adhesive Tape for High Power LEDs, but I can't recall seeing anyone use it here, so I thought it must not be good. There is a Youtube of the guy applying it and it looks as easy as sticking one side on the heatsink and then pressing the LED on. It is double-sided tape that attaches the LED as well as acts as the thermal bond.
http://www.luxeonstar.com/thermally-conductive-adhesive-tape-for-high-power-leds