Thermal Grease or Permanent Arctic Alumina Thermal Adhesive ?

Is there a big enough difference to use permanent Artic Alumina Thermal Adhesive over thermal grease ?

Not sure I want to use the permanent stuff in case the LED goes bad.

What say you ?

http://www.rapidled.com/thermal-grease-and-adhesive/

Thanks

There's a pretty big difference, ime.

I think grease is good enough for 3W LED's and stuff, adhesive seems like overkill to me, especially if you plan to be performing repairs/upgrades later on. Any of the multichip LED's really deserve the expensive stuff, though, imo.

Bumping Spheda said:

There's a pretty big difference, ime.

I think grease is good enough for 3W LED's and stuff, adhesive seems like overkill to me, especially if you plan to be performing repairs/upgrades later on. Any of the multichip LED's really deserve the expensive stuff, though, imo.

Click to expand...

Thanks BS ..appreciate your advice...think I'll go with the grease being they aren't multichip LED's.

i thought just a dot of grease was better to fill the air gaps as aluminum to aluminum contact has the better heat conductivity over adhesive?? please do correct me if im wrong

What exactly are you attaching.. Stars to heatsink? Led to mcpcb?

It really depends on what you're attaching to what, as noted already.

Thermal grease is great if it's easy to screw or clamp the parts together. Good heat dissipation and you can undo it easily.

I'm planning to use adhesive for my next set of lights (for attaching the stars to the heatsinks). I don't have the tools or inclination to drill and tap the heatsinks myself, so I think it's going to be faster, easier and cheaper - for the specific set of lights I'm building next.

This will be the first time I use the adhesive (in a few weeks when my shiny new components arrive), and so if I don't like the first unit maybe I'll get some taps and revert to thermal grease (which has served me well so far with pre-drilled heatsinks).

It should also be noted that I'm pretty confident of what I want from my next lights; the chance of me wanting to change the configuration later is very low. My current set of lights has had a few changes made to its diode selection, so it's a good thing I made them reconfigurable.

You can get arctic silver epoxy which is more thermally conductive than alumina i think.

Personally i love the stuff and use it for mah star-heatsink joints

with grease you would want to be clamping or screwing stars on, though Supra uses only kapton tape and grease.

With EITHER (to the poster above) you want the absolute thinnest layer possible while still filling tiny voids and imperfections in the joint. You could even imagine it as straight metal on metal contact with the grease/epoxy only filling in the cracks where the metal doesnt touch.

edit: just realised this is what you meant

I'm attaching solderless LED's to heatsink which will also be screwed down.


Thanks

If you screw it down you dont need The adhesive one

Just for your knowledge, the two parts adhesive is not that permanent, you can gently tap under with a screwdriver when you need to remove/replace it

jubiare said:

If you screw it down you dont need The adhesive one

Just for your knowledge, the two parts adhesive is not that permanent, you can gently tap under with a screwdriver when you need to remove/replace it

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If I did use grease would it at least help a little with heat or is it more to fill air gaps ?

Rapid recommends something and to not go bare in case of any unevenness
in heatsink.

Would there be any adhesive residue left over if gently removed by tapping with screw driver ?

If you are to screw it down you def get a better thermal transfer with grease

However, the two part adhesive gives it a very good thermal transfer

You ll have a residual yes, once you are to remove it. I do it all the time, all you need is a product like articlean and a little scraper. Quite easy, especially if you are not generous with the adhesive application; a very tiny bit that's all you need, not only for this but for a better thermal transfer!

I actually was gonna open a thread with detailed tutorial about this and reflow, however time is on me! You remind me I should do it soon!

Good luck diyer
ja

Thanks Jubiare very helpful !

Yes start the detailed tutorial... I'm sure it will be very helpful and benefit ( It Helped me ) the DIY'ers and for the many to come down the road.

Having this info all in one place would be fantastic !

Much thanks to people like you who make the internet a beautiful thing !!!

jubiare said:

If you are to screw it down you def get a better thermal transfer with grease

However, the two part adhesive gives it a very good thermal transfer

You ll have a residual yes, once you are to remove it. I do it all the time, all you need is a product like articlean and a little scraper. Quite easy, especially if you are not generous with the adhesive application; a very tiny bit that's all you need, not only for this but for a better thermal transfer!

I actually was gonna open a thread with detailed tutorial about this and reflow, however time is on me! You remind me I should do it soon!

Good luck diyer
ja

Click to expand...

RainerRocks said:

If I did use grease would it at least help a little with heat or is it more to fill air gaps ?

Click to expand...

It helps with heat by filling air gaps with thermally conductive material. Air is a good insulator, so you don't want any of it obstructing the thermal connection to the heatsink. Thermal grease is necessary for proper operation of the LED and heatsink together. Without it or some equivalent, you could have a heatsink which is barely warm to the touch, attached to an LED whose temperature is gradually climbing to the critical failure point.

filling air gaps = helping with heat conducting from the LED's junction to the heatsink. Air is a good insulator.

You could probably use solvents to get the residue off f you use adhesive, but as said before, if screwed down you dont need adhesive.

RainerRocks said:

Is there a big enough difference to use permanent Artic Alumina Thermal Adhesive over thermal grease ?

Not sure I want to use the permanent stuff in case the LED goes bad.

What say you ?


http://www.rapidled.com/thermal-grease-and-adhesive/

Thanks

Click to expand...

You might consider this:
http://www.ebay.com/itm/Thermally-Conductive-Adhesive-Glue-Thermal-Heatsink-BIG-/270717020058?pt=LH_DefaultDomain_0&hash=item3f07fde79a

It's a silicone based adhesive which takes a few days to completely set. It seals the gap, transfers heat well and is removable. I have changed a few stars when tweaking the spectrum. They will pop off with a bit of force but they stay put nicely.

while silicon is pretty decent, IIRC looking up the specs its way inferior to metal-based adhesive or grease. I use silicon adhesive for cheap chinese leds but not for my expensive ones