Machining Copper

One thing I have really been wanting to try is machining my own waterblocks for my pc. I have plenty of experience machining the polycarbonate I intend to use for the tops but I have never machined copper plate. Has anyone had any luck with any copper thicker than the layer on a pcb? I have heard it can be a bugger to machine and and in a previous post the health risks of certain alloys were outlined.

Also, does anyone know of a good source of copper plate ( >5mm)?

Has anyone had any luck with any copper thicker than the layer on a pcb?

I have, although not on a Nomad.

I have heard it can be a bugger to machine and and in a previous post the health risks of certain alloys were outlined.

Yes, be sure you’re using virtually pure copper or - FOR SURE - NOT an alloy containing Beryllium.

You can read about the toxicity of BeCu here:

I will dispute that it is a bugger to machine. I’ve machined 0.5 thick blocks of “110 copper” for my Tesla coil strike rails:

That’s the primary in the center. Digitally modulated pulses of 380VDC@500A are used to energize it. The secondary takes things to over 500KV. The copper blocks are the end points for the strike ring. You can see the supports; the ring itself came later - it goes to earth ground via the knob on the closest block.

For reference, the whole assembly was done with a CNC machine.

My experience is that with a little care and lube it’s about as easy to machine as 6061.

I would check G-Wizard for feeds and speeds, ensure G-Wizard is set for derating for a small spindle/router, use the deflection correction, use AlTiN coated end mills and have a spray bottle with lube in it - the soy stuff works well - and hit it periodically.

Whatever you do, when the job is done, be careful! The end mill, stock and/or piece can be… warm.

Also, does anyone know of a good source of copper plate ( >5mm)?

http://www.onlinemetals.com

mark

P.S.

To show you that even tiny mills can machine virtually pure copper, here is a PocketNC doing so. It has a slightly more powerful spindle than the Nomad does. One can note the lubricant - not very much and certainly not dripping all over the place.

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What common scrap copper usually contains Beryllium? Or can I tell via some test if the copper has Beryllium?

What common scrap copper usually contains Beryllium? Or can I tell via some test if the copper has Beryllium?

I’m not aware of simple tests for Beryllium. Also, other ingredients for Cu alloys can make them fairly hard… not something one would probably want, especially when starting out.

Two types of commercial Cu that are known to be safe - and machine well - are “101 copper” and “110 copper”. Both are 99.9% pure Cu - what’s not Cu is known to be safe. There are other safe alloys but they get pretty hard.

The “101 copper” is the “oxygen free” Cu often associated with expensive audio cables.

If you choose “110 copper” I would recommend “060” or “H02”. Stay away from “H04” (full hard temper) until you’ve mastered something softer.

mark

I have a small furnace that I melt scrap aluminum to use. I was going to melt down some scrap copper - pipe, wire, cooking utensils - and use that also. I’m guessing I should find more info on the scrap copper alloys before continuing.

I have a small furnace that I melt scrap aluminum to use. I was going to melt down some scrap copper - pipe, wire, cooking utensils - and use that also. I’m guessing I should find more info on the scrap copper alloys before continuing.

Electric wires would be fine. I can’t speak to “scrap”. My instinct says that “utensil” will be one of the tougher copper alloys that you don’t want to start learning on - and may be one of the nasty ones.

mark

Thanks Mark, as always a perfectly thorough answer!

Yes, Mark, thank you for the insight and precautions!

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Copper is a lot more difficult to melt than aluminum. In its pure form, it doesn’t melt until 1984 Degrees Fahrenheit, and you’ll want to go over that to get it fluid enough to pour. You can’t use a steel crucible which might work okay for aluminum (although it’s not recommended for that). Get a clay-graphite or silicon carbide crucible and the tongs to hold onto it.

Ingots of copper that you pour into steel molds (make sure to pre-heat them before pouring to eliminate all traces of water) won’t be as good as billet, since they will have some porosity inside from shrinkage.

Andrew Werby

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