Which Spindle coolant to use?

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Stone

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I just received my new CNC Mini mill. It has a 2.2 kW water-cooled spindle and I have heard from friends that I need to add something to the distilled water to prevent rusting.

Most people have told me to add antifreeze to the water at 2:1 ratio. When I google on the subject some have reported that certain types of antifreeze cause clogging up in the spindle. There are different types of antifreeze (blue, green, red, etc), not all are suited for the job.

I am looking for something to stop the rust and prevent algae growth in the water when it stands for long periods.

I live in South Africa so often a branded product, like Motorex COOL-X , is not viable and importing fluids cost to much due to the volume and weight.

Can anyone suggest a good DIY formula? E.g. propylene glycol + antirust additive + algae inhibitor

Any help appreciated!
 
Hot water heating systems or in your case that's more likely to be chilled water systems, would have similar problems. You might check with Heat-Ventilating-Air-Conditioning companies in your area to see what they would recommend.
 
If you are using an open system like a cooling tower you will need to dump water to kill the algae problem also a cooling tower as it runs causes any mineral content To be increased, This causes scaling problems if the water isn't changed fairly often. You didn't say haw you are getting the heat away from the water after it cools the spindle. That would also provide information needed for haw much water you will need.

Art B
 
Last edited:
I just received my new CNC Mini mill. It has a 2.2 kW water-cooled spindle and I have heard from friends that I need to add something to the distilled water to prevent rusting.

Most people have told me to add antifreeze to the water at 2:1 ratio. When I google on the subject some have reported that certain types of antifreeze cause clogging up in the spindle. There are different types of antifreeze (blue, green, red, etc), not all are suited for the job.

I am looking for something to stop the rust and prevent algae growth in the water when it stands for long periods.

I live in South Africa so often a branded product, like Motorex COOL-X , is not viable and importing fluids cost to much due to the volume and weight.

Can anyone suggest a good DIY formula? E.g. propylene glycol + antirust additive + algae inhibitor

Any help appreciated!
Depends on how you cool the water. I would be tempted to modify a air conditioner for that service and use a glycol with a rust inhibitor. Basically a closed loop system. And if you are worried about solids put a filter in the line before the spindle.
 
In South Africa the different colour antifreeze mixes are difference concentrations mixed to the Car manufacturers specs ie if the dealer supplies green antifreeze then that the mix required for say Toyota, and say red for Ford. In some cases the concs are the same irrespective of the colour, so check your cars manual and the colour in your header tank and that will be the concentration
 

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