Thread: How to cut very fine channels in copper?

Hi guys im new here so firstly hello to all!

I want to create my own waterblocks for my pc water cooling rig and one of the things the copper block needs is as many channels milled into it as possible. I was just wondering what is the best way to carve very fine channels into metals, ideally without using a milling machine as i dont have access to one but i also doubt there are tools fine enough to achieve this.
Ideally i would want the width of each channel to be no bigger than 0.5mm but the finer they can be cut the better!
So do you guys have any ideas on how i can cut fine channels into copper?

If your struggling with my explanation what im trying to achieve is something similar to this......
cpu block fins.jpg
Thanks guys!

Hi Digital,

Welcome to the Metalwork forums,

Let me say I have little experience with copper work, but given there is no milling machine available, perhaps a dremel type tool with a fine bit might do the job. I dare say some fixture needs to be involved.

I do know some copper alloys have a component beryllium a carcinogenic,so respiratory protection is a given.

Some dimensions of the intended block might help us better identify a technique or process needed.

Other members will be along soon to add their ideas.

Grahame

Given what you have available, I wouldn't do it the way you are thinking at all. Solid copper is very expensive, and in this instance most of it will simply be removed anyway. Why is it that you don't just buy or modify a commercial offering?

If you did want to make it I'd suggest instead of removing material, add it together. Cut circa 0.5 mm copper sheet into wide and narrow strips, the wide strips are the heatsink itself, the narrow strips the spacers between the fins. Make up a template to drill 2 holes in each strip in the same position. To make the heatsink just stack the strips together, alternating between wide and narrow strips and using a couple of aluminium pins to keep the whole lot aligned. Once assembled peen the ends of the aluminium pins to secure your stack and flow some solder into the bottom of the stack to help with heat conduction in its role. Complete by sanding the bottom smooth.

While that would be the easiest way I can think of to make this item, I still think it is a monumental waste of time given that something similar can be purchased off the shelf far cheaper and arguably than it could ever be made.

For fine work like that you could use the same technique as for making electrical circuit boards - ie. acid etching.

Mark out the item and let acid eat away the exposed copper areas to the depth you require.

Look up circuit board etching for the full guts on the process involved.

Cheers Rob

I agree with Peter that this is going to be a lot of trouble given that you can buy these things off the shelf. It reminds me of my son's efforts 20 years ago in water cooling PC processors using a Toyota Corolla radiator and water pump and a pedestal fan. It worked but there were quite a few leaks and after he flooded his bedroom it had to go outside.

My understanding is that these fins are either cast into a hot cold or fusion welded onto a relative thick copper base using a very fine specialised laser welding unit. PeteFs method is probably the easiest DIY solution but the solder won't be as conductive as a copper direct connection.

The main problem with using any sort of cutting method is preventing the copper from galling on any blade.

Slightly off topic but still somewhat related..

I find the advent of water cooling for PCs mildly amusing. I have worked in the mainframe computing world for 45 years and liquid cooling of mainframes has been around for much of that time.
When the PC first appeared on the scene the newly minted zealots gave us "big iron" people stick over how antiquated the concept of having to water cool a computer was - and all these years later they've learned the same lesson that the mainframe designers learnt all those years ago.

In the same vein, the PC world touted that the PC provided the freedom of computing power on everyone's desk and the liberation of central control, and decried the mainframe concept of dumb terminals connected to central computing resources (think IBM 3270).
Now all these years later after realising how hard it had become to manage that arrangement in large scale installations, the wheel has been re-invented with "thin clients" where the device on the desk is totally dependent on a central server for all it's code and data.

The more things change, the more they stay the same it seems.

Originally Posted by Gavin Newman

Slightly off topic but still somewhat related..

Now all these years later after realising how hard it had become to manage that arrangement in large scale installations, the wheel has been re-invented with "thin clients" where the device on the desk is totally dependent on a central server for all it's code and data.

Ha Ha. I also worked in IT at many levels for 20 years and I can only say the wheel will continue to turn.

Thin clients biggest downfall is the time wasted while every PC runs off to the server, particularly at boot time. Coffee any one ? We went that way and came back to installed apps after the spin doctors moved on.

There's always some guru sprouting stuff that's been tried before and failed.

Anyone remember "process re-engineering" - LOL

Cheers Rob

Originally Posted by nearnexus

For fine work like that you could use the same technique as for making electrical circuit boards - ie. acid etching.

Mark out the item and let acid eat away the exposed copper areas to the depth you require.

Look up circuit board etching for the full guts on the process involved.

Cheers Rob

That won't work for deep etching like that. The etchant will undercut the fins and won't etch straight down as you suppose.

Bob, the solder is there just to keep the whole lot tightly bonded, and the ends of the copper strips are still the contact points. In any case modern solders are still quite heat conductive, albeit not as conductive as the copper, however the solder would be extremely thin and the thermal properties immaterial in practice. The above is basically how magnetic transfer blocks, chucks, etc are made. I agree, I believe the commercial units are welded to a machined substrate.

A slitting saw would be the way you'd do this if it HAD to be done in one piece, but in my opinion it would be a monumentally stupid idea to go down the path of machining something like this.

Thin fins on copper heatsinks aren't milled or cast, they are skived off the parent block. Effectively, they're peeled off. Not a job one can do at home.

I very much doubt you'd be able to manufacture 0.5mm fins in copper subtractively with conventional hand tools, let alone machine tools.

Originally Posted by Pete F

That won't work for deep etching like that. The etchant will undercut the fins and won't etch straight down as you suppose..

Yep etching works only for depths that are much less than the width of gap being etched.

jmm292181fig01.jpg

Bob, the solder is there just to keep the whole lot tightly bonded, and the ends of the copper strips are still the contact points. In any case modern solders are still quite heat conductive, albeit not as conductive as the copper, however the solder would be extremely thin and the thermal properties immaterial in practice. The above is basically how magnetic transfer blocks, chucks, etc are made. I agree, I believe the commercial units are welded to a machined substrate.

Makes sense

A slitting saw would be the way you'd do this if it HAD to be done in one piece, but in my opinion it would be a monumentally stupid idea to go down the path of machining something like this.

Agree

Originally Posted by Pete F

That won't work for deep etching like that. The etchant will undercut the fins and won't etch straight down as you suppose.

I didn't expect it would do a straight etch without undercut, but for something simple like a radiator channel the shape shouldn't really matter.

A slitting saw or small engraving/pcb mill are probably the only other options. But that's not much good if you don't have the equipment.

Cheers Rob

Originally Posted by nearnexus

I didn't expect it would do a straight etch without undercut, but for something simple like a radiator channel the shape shouldn't really matter.

It does matter, and having done etching of copper alloys like brass (as well as standard circuit boards obviously) I can assure you that there is no hope in hell of etching 0.5 mm width parallel fins that were that deep.

Etching is an excellent way to make very nice looking signs etc. I've done it where I used vinyl labelling to create the lettering, then sprayed it with an oil based paint to create the mask, removed the lettering and etched the work, then finally infilled the etched areas with black epoxy to create very durable lettering that won't rub off etc. In brass however the etching isn't as consistent as it is with more pure copper, and the surface left is rough. That in itself if fine for that application, but it would be something to keep in mind.

The process is used extensively in the aerospace industry these days, as a way to lighten panels etc. I've never etched aluminium so can't say how it works in a home shop.

I know this probably sounds a bit silly but would a Jap cross cut pull saw do the job?
They cut a super fine kerf well under 1mm and would definitely be hard enough to cut copper... and no machines involved.

Originally Posted by Gavin Newman

Slightly off topic but still somewhat related..

I find the advent of water cooling for PCs mildly amusing. I have worked in the mainframe computing world for 45 years and liquid cooling of mainframes has been around for much of that time.
When the PC first appeared on the scene the newly minted zealots gave us "big iron" people stick over how antiquated the concept of having to water cool a computer was - and all these years later they've learned the same lesson that the mainframe designers learnt all those years ago.

In the same vein, the PC world touted that the PC provided the freedom of computing power on everyone's desk and the liberation of central control, and decried the mainframe concept of dumb terminals connected to central computing resources (think IBM 3270).
Now all these years later after realising how hard it had become to manage that arrangement in large scale installations, the wheel has been re-invented with "thin clients" where the device on the desk is totally dependent on a central server for all it's code and data.

The more things change, the more they stay the same it seems.

Originally Posted by nearnexus

Ha Ha. I also worked in IT at many levels for 20 years and I can only say the wheel will continue to turn.

Thin clients biggest downfall is the time wasted while every PC runs off to the server, particularly at boot time. Coffee any one ? We went that way and came back to installed apps after the spin doctors moved on.

There's always some guru sprouting stuff that's been tried before and failed.

Anyone remember "process re-engineering" - LOL

Cheers Rob

AH AH so its your fault we HAD to have de-humidification and humidification auto controlled this, auto controlled that, underfloor server room slapped together airconditioning units that always broke down and costs a fortune up front and to service every damn week.... I will remember you two for the rest of my life....lol

eskimo.

In the words of the philosopher, Maxwell Smart - "Sorry about that chief".