Which is the most suitable termal paste to use between diode and heatsink?

[Minamoto Kobayashi]

I wish to use thermal compound to eliminate the small air gap between a diode pressed in a copper module and the heatsink (copper or aluminum). Here I have Arctic MX III and Arctic MX IV, but I think there could be other better compounds .. any ideas or suggestions?

 

[ChaosLord]

The artic alumina ceramic is the one I use. I've seen many others use it as well. One of the main advantages besides excellent thermal conduction is that it doesn't conduct electricity.

 

[Minamoto Kobayashi]

Good!
But there are some situations that the diode case requires to receive a polarity from the host. So, in that case the thermal compound may be a big problem, right?

 

[ChaosLord]

I don't think so. As long as the diode is wired into the host according to grounding, it shouldn't be a problem if there's conduction between diode/module/heatsink.

Example: if diode is case positive, and you wire the driver/host as positive ground, then if there is conduction between diode and module/heatsink it would be fine. If there is no conduction, it would still be fine.

As far as I know, this is only a problem when you have a case polarized diode that is the opposite of the host polarization. If they are opposite, you would have to isolate the diode. This can be avoided if you wire the host/driver for the same polarity as the diode.

 

[Minamoto Kobayashi]

Hi.
I have tried the thermal compound with this kind of module, and do not work anymore:

Also the first version of the Frankenstein kit with the 445 nm M140 diodes (with the case pin positive) stop to works if thermal compound is present between the diode case and the heatsink.
Probably some diodes requires an electrical path directly to the case to work ...

 

[Minamoto Kobayashi]

I have solved the problem with this excellent product:

Coollaboratory Liquid Ultra + Cleaning Kit CPU Thermal Compound | eBay

This compound has exceptional performances, far away from the alumina ceramic one, and it is conductive, so if my diode case needs a current path, this is what I need!

 

[ARG]

There wont be much of a difference, especially at these low powers.

 

[Minamoto Kobayashi]

Yes I know. But there is a level called "maniacal" that also a -0.5 °C result compared with other compounds will create a sort of unmotivated enthusiasm

 

[Minamoto Kobayashi]

Update: I cannot use la Liquid Ultra because is corrosive for the aluminum heatsinks ;(

 

[ryansoh3]

Update: I cannot use la Liquid Ultra because is corrosive for the aluminum heatsinks ;(

Yes, liquid metal is corrosive and should be avoided. Unless you're a hard core over clocker, haha.

 

[Blarg King]

If conductivity isn't needed then I suggest Arctic MX 4. Its what I use to heatsink my high power LED's.

 

[Minamoto Kobayashi]

Yup I have used MX4 for a while, but now I have bought this one:

Amazon.com: Prolimatech PK-3 Nano Aluminium Thermal Compound 1.5g: Computers & Accessories

that is a very good compound that many guys have suggested me for its high
performances.
Anyone has already tried it?

 

[NKO29]

I use AS alumina epoxy... Non conductive and keeps the modules in spot FOREVER! Seems to have pretty good heat transfer, as the gap in heatsinks is VERY small.