A little lesson on heatsinks

[grainde]

Wonder how the copper is holding up at the interface of the aluminum sink... Copper chloride w/aluminum poof.

Its not, as you well know....

Ive mentioned it three times already, but the thermal epoxies/ greases we use, only have a thermal conductivity of around 3 Wm-1K-1.

Now think of all the interfaces (not including those within the diode itself) diode:module, module:heatsink, heatsink:host! Unless these have been constructed with very, very tight tolerances your thermal grease and possibly air will be inhibiting heat flow to the host.

Direct press heat sinks, which themselves are are pressed into the host or simply direct press hosts would be much better! Think MS V1-V4, Kryton etc

Only problem is these arent particularly big hosts...So perhaps we should think about some copper versions. I wouldnt mind the tarnishing and think it could actually look really good...:beer:

 

[EpicHam]

Its not, as you well know....

Ive mentioned it three times already, but the thermal epoxies/ greases we use, only have a thermal conductivity of around 3 Wm-1K-1.

Now think of all the interfaces (not including those within the diode itself) diode:module, module:heatsink, heatsink:host! Unless these have been constructed with very, very tight tolerances your thermal grease and possibly air will be inhibiting heat flow to the host.

Direct press heat sinks, which themselves are are pressed into the host or simply direct press hosts would be much better! Think MS V1-V4, Kryton etc

Only problem is these arent particularly big hosts...So perhaps we should think about some copper versions. I wouldnt mind the tarnishing and think it could actually look really good...:beer:

"Now you TOO can look like a Plumber ! "
Copper Laser Industries presents!
FULL COPPER LASER!
COPPER DIODE MODULES!
COPPER HEAT SINK!
COPPER HOST!
COPPER GRIP!
COPPER THREADS!
COPPER EVERYTHING!

Coppermania!

 

[hwang21]

Lol. So 20 years for copper to corrode beyond operation... so in 20 years, your laser would be short 1 heatsink? :thinking:

 

[EpicHam]

Lol. So 20 years for copper to corrode beyond operation... so in 20 years, your laser would be short 1 heatsink? :thinking:

That is a 1000 year old artifact from west africa.

And this!
Is a 40 year old copper hot water pipe .

Don't worry.
Your heatsink won't be turning green on you any time within the next 5 years

 

[grainde]

It will actually turn black and green etc in a matter of days, if you are constantly touching it. The water, salts and acids in your sweat help speed up the corrosion. :beer:

 

[hwang21]

Ok well it's a heatsink, I'd only be touching the focusing ring a bit but I don't like the fact that it will discolor in days/weeks. That's annoying

 

[grainde]

Yup just mentioned it, cos Epic was going copper crazy and wanting the world to turn to copper...lol :beer:

 

[hwang21]

Lol and so now we turn to creating a protective layer for copper, cheaply, like anodizing aluminum...

 

[grainde]

You can use a lacquer like clear nail varnish...:beer:

 

[hwang21]

Hmm interesting idea :beer:

 

[grainde]

You could also try plating the copper with zinc. Have a read through the link below, it would be very easy!

ChemLab 23 - Chemical Plating of Copper with Zinc

:beer:

Edit: stumbled on this pic as an example:

 

[hwang21]

Intersting, would this electroplating process keep the surface nice and coppery-shiny? Or would it be more silver-ish from the Zinc?

 

[grainde]

It would look like a silver /gold.

Here's a quote from that link chemlab 23:

"When you heated the coins the zinc combined with the copper, forming a bronze coating. Because the bronze is high in zinc, your coins look "gold"."

Only thing is bronze will also corrode, but it will be better than pure copper. You could plate with a different metal as well, but youd have to check up the electronegativities and redox chem.

I think a Ti host would look the best though; especially anodized. Who cares about thermal conductivity when it looks this cool.

Take a look at this thread if you want to see some awe inspiring work...

http://laserpointerforums.com/f66/fred-s-block-party-hosted-mokuti-72689.html


:beer:

 

[Zoidberg]

.925 silver. Guys need to be thinking of alloys. The thermal properties of silver and copper combined. Gallium cored, diamond dust impregnated .925 silver. This is what my PC's heatsink is made of with it seated with IC diamond 24k diamond thermal compound. The processor runs at an oc'ed freq of 4.89 ghz, The core has yet to hit 103°f. All the talk of materials to use for the heatsink has been discussed for years and years. What I see most people on here not paying any attention to is the thermal compound and proper usage of it. I may make a thread just for thermal compounds to supplement these threads about heatsinks. Keep up the good work everyone!

 

[ApexProxy]

As EpicHam mentioned earlier copper can be anodized like aluminum. Though I don't know how that effects its physical properties. I suspect its not all that drastic since its rarely done.

I propose instead we gold plate our copper heatsinks haha. If someone can locate an affordable means to do this.

 

[hwang21]

Agreed^