CNC an aftermarket heatsink?

[1461748123]

Hey guys! I'm recently working on my water cooling S4M build.
I need a custom heatsink for my GPU, but making one from scratch will be crazy expensive, so I'm looking a method to machine an exist aftermarket heatsink.
My idea is, by using expanding spray foam, I can fill in the gaps between the fins. When the foam is hardened I should be able to just mill the shape I want out. After CNC, I can just dissolve the foam with acetone. But I've never really had any experience with CNC so I'm not sure if this idea will work or not...
Any help will be appreciated!

 

[XeaLouS]

Just a note that you have to take care of heatpipes too (don't cut them).

 

[1461748123]

Just a note that you have to take care of heatpipes too (don't cut them).

Yep! I should add that the heatsink I'm working with is this kind:

Essentially just a block of copper.. but with a lot of slots.

 

[jtd871]

Here's a thread with some responses:
http://www.practicalmachinist.com/vb/general/machining-copper-199333/

 

[thewizzard1]

Using an abrasive waterjet, it'll be far easier to cut the heatsink's fin as you need, then a traditional milling op for the base and mounts.

 

[|||]

Using an abrasive waterjet, it'll be far easier to cut the heatsink's fin as you need, then a traditional milling op for the base and mounts.

I don't think he's trying to cut all the way through the material, just shave the fins off.

Hey guys! I'm recently working on my water cooling S4M build.
I need a custom heatsink for my GPU, but making one from scratch will be crazy expensive, so I'm looking a method to machine an exist aftermarket heatsink.
My idea is, by using expanding spray foam, I can fill in the gaps between the fins. When the foam is hardened I should be able to just mill the shape I want out. After CNC, I can just dissolve the foam with acetone. But I've never really had any experience with CNC so I'm not sure if this idea will work or not...
Any help will be appreciated!

Another way could potentially be getting a small piece of copper pipe with the OD the diameter of the cut-out you want. You'd use the copper pipe as the tool in a die-sunk EDM to cut around the part of the fins you want removed. You can then CNC out the fins within without concern for the part you want to preserve.