How do they solder heatpipes to heatsink?

[erwin1978]

Can someone link me a video of how they solder heatpipes to heatsinks? I used a blowtorch to disassemble my heatsink and the flat heatpipes became rounded. I want to undo this.

 

[Wall Street]

Can someone link me a video of how they solder heatpipes to heatsinks? I used a blowtorch to disassemble my heatsink and the flat heatpipes became rounded. I want to undo this.

Short answer : in a factory with a machine. Doubt you will be able to duplicate their results doing it by hand.

 

[Kenmitch]

Can someone link me a video of how they solder heatpipes to heatsinks? I used a blowtorch to disassemble my heatsink and the flat heatpipes became rounded. I want to undo this.

So the contacts points that used to be flat expanded? If so not much you could do other than maybe heating them up and pressing them done flat again. Maybe make a jig? Use old heatsink base?

Pictures of your project might help with ideas.

 

[Vinwiesel]

I always assumed they soldered the heatpipe to the heatsink before the pipe was sealed. Did the pipes bulge from the internal pressure?

 

[erwin1978]

Here's the story. I have a Geforce GTX 295. Everyone knows this card runs hot. I was looking at the heatsink and noticed some of the exposed fins aren't soldered to the aluminum plates. I thought I would reflow some solder just to make it more efficient. I placed the heatsink in an oven and monitored the temperature with a thermocouple placed inside the fins. I also placed a tiny piece of 63/37 solder on the aluminum just so I can see when it starts melting.

I believe they used lead free solder since there is a RoHS label on the card. The temperature went passed 183° C and the test solder hasn't melted so I waited until it reached over 200° C. I then noticed the aluminum plates were separating and bowing at the center. I went into panic mode and abandoned ship. After everything cooled down I could see the pipes slightly rounded and not so flat. I don't think they caused the aluminum to bow out because the aluminum is bulging further out. Yes, I think the heat caused the gases inside the pipes to bulge it. Hopefully, it did not out-gas.

The only way to fix this is if I completely separate the heatpipes from the aluminum plates. I would then flatten the the pipes so they can fit back into their slot. Put more solder paste and clamp it all down before going to the oven once again. Do you think 63/37 solder will be strong enough or do I need silver solder?

 

[VirtualLarry]

buy a new cooler? Third-party?

 

[Gunbuster]

Yeah time for a 3rd party cooler or to upgrade from the GTX 295.

 

[Vinwiesel]

I would agree on getting a 3rd party cooler. Even if you can somehow manage to flatten the tubes and mill them perfectly flat, most of the other contact joints have probably been fractured in the cooler. The tubes may no longer contact the fins properly, and then there is the chance that the tubes are damaged internally from being overpressured and will not wick properly anymore.