Tekno_Cowboy
Flashlight Enthusiast
Just a thought: would super glue work well as a thermal adhesive?
Super Glue for Thermal Adhesive
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A380
Newly Enlightened
I'm not sure but I think no. Super-glue (cyanocrylate) is flammable.
Tekno_Cowboy
Flashlight Enthusiast
Even dry?
kramer5150
Flashaholic
I tried it once and the fumes made one of my XRE domes foggy. well... I used AS-5 in the middle and placed 3 dabs of superglue gel around the heatsink disk, and pressed it flat. Another member later told me I should have placed it infront of a fan to circulate the air around it.
A380
Newly Enlightened
Yes, even dry. Just try it; put some drops on a non flammable material (stone for example), let it dry and put a flame on it.
I found one reference to it's thermal conductivity being 0.1W(m.K). Not great compared to copper ~400 or aluminium ~180. I've used it to secure a luxeon emitter sitting on thermal grease, reinforced with microspheres. It's holding up fine in a minimag with heaps of use.
kaptain_zero
Enlightened
- Joined
- May 31, 2010
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For all intents and purposes, CA or Super Glue, once cured, is simply Acrylic Plastic.
For a more in depth article on CA glues, do a google search for "cyanoacrylates.html" which takes you to a wood turning site where the author has done some serious research on the topic.
Regards
Christian
For a more in depth article on CA glues, do a google search for "cyanoacrylates.html" which takes you to a wood turning site where the author has done some serious research on the topic.
Regards
Christian
Its not that much worse than most of the typical cheap "white goo" thermal paste.
The main point is: If you are used to it, and using superglue helps you make a very thin interface layer, no problem with it.
The glue being flammable is of no convern for its heatsinking capabilities. In case of a thermal rundown, PVC wires are just as flammable and much more toxic.
Plus, if you use it correctly, you will only have a very tiny amount of the glue in use, without contact to any air.
The main point is: If you are used to it, and using superglue helps you make a very thin interface layer, no problem with it.
The glue being flammable is of no convern for its heatsinking capabilities. In case of a thermal rundown, PVC wires are just as flammable and much more toxic.
Plus, if you use it correctly, you will only have a very tiny amount of the glue in use, without contact to any air.
If you go on the numbers, CA could be many hundreds times worse than a basic thermal transfer paste. How that translates in real world performance is hard to say. The unknown factor is the thickness of the layer, which depends on the thickness of the CA used and the pressure applied. "Thin" grade CA is really really thin, but the downside is you'd have pretty much no positioning time as it goes off really quickly.
Light Sabre
Enlightened
One problem with super glue is that when it dries, it becomes brittle and susceptable to breaking apart. Dropping your flashlight and cracking the super glue would then separate the 2 pieces and then you would have a gap and loss of any kind of thermal properties. Super glue will also out gas when heated up and then get deposited on anything nearby. :thumbsdow
At work we use epoxies for the most part. And not the 5 minute kind either. Most of the epoxies we use, don't become brittle when dry. They are more like the tread on your car tires. If you use your finger nail and press into it, you will see the impression in the epoxy. We do use a thermal epoxy that does get rock hard, but it is not brittle at all.
At work we use epoxies for the most part. And not the 5 minute kind either. Most of the epoxies we use, don't become brittle when dry. They are more like the tread on your car tires. If you use your finger nail and press into it, you will see the impression in the epoxy. We do use a thermal epoxy that does get rock hard, but it is not brittle at all.
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Justin Case
Flashlight Enthusiast
- Joined
- Mar 19, 2008
- Messages
- 3,797
Cree datasheets explicitly warn against exposing the Cree dome to super glue fumes, which can cloud it as Kramer discovered. Don't know about other LED domes, but I personally would not take the chance.
In addition, the bond strength at elevated temp is poor, especially in the presence of a humid environment.
Finally, thermal conductivity is low, probably at least a factor of 10X lower than AA epoxy.
Thus, super glue seems to me to be a poor choice for a thermal adhesive. It's not much of an adhesive when things get warm and humid, and it doesn't transfer heat well, which will help get things warm. And it can damage your LED as well.
In addition, the bond strength at elevated temp is poor, especially in the presence of a humid environment.
Finally, thermal conductivity is low, probably at least a factor of 10X lower than AA epoxy.
Thus, super glue seems to me to be a poor choice for a thermal adhesive. It's not much of an adhesive when things get warm and humid, and it doesn't transfer heat well, which will help get things warm. And it can damage your LED as well.
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Tekno_Cowboy
Flashlight Enthusiast
Looks like a big old fat "no" is the answer. Perhaps someone knows of a fast setting non heat-curing thermal adhesive other than Arctic Alumina adhesive. I'm looking for something that comes in larger quantities than the AAA, or in lieu of that, easier to find locally.
65535
Flashlight Enthusiast
Arctic Alumina, or Arctic Silver you may be able to find larger quantities, I think some have in the past and did a group buy. The stuff doesn't have much of a shelf life so having large quantities really isn't idea.
precisionworks
Flashaholic
Devcon Tru-Bond 215 might work:
http://www.devcon.com/techinfo/Tru-Bond_215.PDF
Thermal Conductivity is listed at 0.98 W/m-K
http://www.devcon.com/techinfo/Tru-Bond_215.PDF
Thermal Conductivity is listed at 0.98 W/m-K
Tekno_Cowboy
Flashlight Enthusiast
There's a similar product to AAA, but you have to have a business license to buy it, which I do not.
Since I mod a quite a few lights, and I've been using AAA to pot some of my lights, it goes pretty fast. I go through a 5g set of AAA in about 3 weeks...
The Devcon will not work because it is electrically conductive.
Since I mod a quite a few lights, and I've been using AAA to pot some of my lights, it goes pretty fast. I go through a 5g set of AAA in about 3 weeks...
The Devcon will not work because it is electrically conductive.
spc
Enlightened
Ive heard of others mixing regular 2-part devcon epoxy with some kind of AL powder. I would like to know what kind of powder and what mixture. This may be alot easier to get in large quantities..
Very fine aluminum oxide powder:
http://mamasminerals.com/products/Pro%252dPolish-%280.5-Micron-Aluminum-Oxide%29-Rock-Polishing-Powder,-1-Lb..html
Don't sneeze anywhere near it. Try a search. This has been extensively covered.
http://mamasminerals.com/products/Pro%252dPolish-%280.5-Micron-Aluminum-Oxide%29-Rock-Polishing-Powder,-1-Lb..html
Don't sneeze anywhere near it. Try a search. This has been extensively covered.
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spc
Enlightened
thanks saltytri :thumbsup:
looks like a 50/50 mix of the aluminum oxide powder and devcon epoxy works well + a 1lb bag like the one saltytri linked would last a while!
looks like a 50/50 mix of the aluminum oxide powder and devcon epoxy works well + a 1lb bag like the one saltytri linked would last a while!
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Tekno_Cowboy
Flashlight Enthusiast
I suppose the simpler thing to do would be to just get some potting compound and use the AAA for only mounting LEDs.
If you do use this Will, what is your method for mixing it?
If you do use this Will, what is your method for mixing it?
