Artic thermal compound differences?

I looked on their site quickly, but what's the performance difference between all the Artic thermal compounds? What do you guys prefer and/or have noticed works the best?

Arctic Silver 5 High-Density Thermal Compound

Arctic Silver Ceramique High-Density Thermal Compound

Arctic Alumina Ceramic Thermal Compound

Arctic Alumina Adhesive (two-part Epoxy)

Arctic Silver Thermal Adhesive (two-part epoxy)

Are the "Adhesives" ONLY adhesives?...or do they have thermal conductivity also?
Do the Thermal Compounds perform adhesion also?
Thanks,
J.

the adhesive's have thermal conduction properties. the thermal compounds are not to be used for adhesive applications and they have better thermal conductivity than the adhesives

Hmmm, from the Arctic Silver website:

"Negligible electrical conductivity.

Arctic Silver Thermal Adhesive was formulated to
conduct heat, not electricity.
NOTE: Even though Arctic Silver Thermal Adhesive is specifically engineered for high electrical resistance, it should be keep away from electrical traces, pins, and leads. The cured adhesive is slightly capacitive and could potentially cause
problems if it bridged two close-proximityelectrical paths."


Is this conductivity enough to be a problem when heatsinking a Luxeon?

Thanks for the info, but I'm still a bit confused on the differences between all the compounds. If the thermal compounds aren't at all adhesive, how do they keep the heatsink on the CPUs (since they're designed specifically for that)?
What do most people use when modifying lights? Are they concerned more with adhering the Star or Emitter in place or ensuring thermal conductivity?

branny - I wouldn't worry much on the electrical isolation of the heatsink slug on Luxs. I asked around and most people don't know the exact consequences, but most have not seen any issues with electrical connection between the heatsink slug and one of the pins on the Lux. Many flashlights use the body as both a return path and heatsink, which means the slug (which isn't electrically neutral) is connected to the LED cathode, which the datasheet says not to do, but it likely doesn't hurt the Lux as I believe it only lowers the ESD withstanding capability of the Lux.

jsr said:

Thanks for the info, but I'm still a bit confused on the differences between all the compounds. If the thermal compounds aren't at all adhesive, how do they keep the heatsink on the CPUs (since they're designed specifically for that)?
What do most people use when modifying lights? Are they concerned more with adhering the Star or Emitter in place or ensuring thermal conductivity?

branny - I wouldn't worry much on the electrical isolation of the heatsink slug on Luxs. I asked around and most people don't know the exact consequences, but most have not seen any issues with electrical connection between the heatsink slug and one of the pins on the Lux. Many flashlights use the body as both a return path and heatsink, which means the slug (which isn't electrically neutral) is connected to the LED cathode, which the datasheet says not to do, but it likely doesn't hurt the Lux as I believe it only lowers the ESD withstanding capability of the Lux.

Click to expand...

You want to glue an emitter to a heatsink or fill a sammie? Use the Artic Alumina epoxy (adhesive).

Want to enhance thermal conductivity and maintain electrical connectivity (say, when the heatsink is your NEG path also)? Use Artic Silver Thermal compound.

Want to enhance thermal conductivity but don't care about electrical isolation? (as in enhancing thermal path of an o-sink in a MagD mod) Use the Artic Alumina thermal compound.


As far as isolating the slug from the heatsink, that's only critical to do in white emitters and when you have more than one on a single heatsink. If you don't isolate them, they'll short out= smoke. Usually the thermal epoxy is enough to provide isolation. You must isolate the slug of all Red/Orange Luxeons (and some other ones I can't remember right now).

Hope that clarifies things.

Thanks green! Much appreciated.

J.

I just talked to a rep from Arctic the other day, and he stated that the Ceramique compound will provide the best thermal conductivity over time for any of their products as the particles in the paste are able to rearrange themselves and "settle" in. He also mentioned why they do not provide information on measurements of their products' thermal conductivity, which I thought would be nice for comparison to products made by others such as Tra-bond. He said those numbers don't tell the whole story because most products make poor contact to the solid surfaces (something like 20-30%). He said Arctic products have been formulated to improve wetting behavior and therefore he is confident that they make the best thermal compounds. The rep also added that the conductivity issue of the Arctic Silver Thermal Adhesive will not be an issue because the capacitance of this material is such that it will only pass signals that are at very high frequencies, so it might be a problem in some telecommunication applications, but not for a DC powered flashlight.

Also, there is no problem with allowing the slug of a white Luxeon I or III emitter to contact ground, provided that you do not have multiple LEDs in series sharing that ground connection. There are some great explanatory posts on this subject.

Hi all
I just made up a pair of BBNextGen powered red Luxeons for a lightsabre project for the kids. Eveything was working fine until I used some leftover Arctic Silver Thermal Adhesive to tack the reflectors in place over the LEDs. At next power-up both emitters lit momentarily then went out- forever. Testing showed the LEDs are OK but both Badboys are toast- in fact the ground wire melted off each e-can.
Anyhow- just take this as a warning that low conductivity may not be as safe as one might think.....

Good luck all.

Hi,
I used Arctic Silver to glue WXOS to O-sink. It works. Arctic Silver is not conductive when it's dry up.
Just be carefull and make sure that epoxy is between Luxeon slug and heatsink - I mean slug is not touching heatsink directly. Measure that with multimeter to be double sure.