Water cooled spindle coolant?

Working on my liquid cooling loop, I am running clear hoses. Does anyone know about Blue antifreeze, is this type ok for use with a spindle/chiller? My Lightobject 1600 has a 2.5 gal reservoir, and I much prefer the color blue over green. I can run this straight no additives? Also should I incorporate a silver bullet inline?


Blue Antifreeze 50/50 mix

Anti Bacterial Silver Bullet Fitting

1 Like

The silver bullet is a nice widget.

I was not able to find any spec from the spindle vendors for what to run.

I’m running blue automotive anti-freeze as a corrosion inhibitor (regular ethylene glycol) plus some anti microbial / antifungal additives. I’ve had no problem so far, since increasing the level of anti microbial in the summer and flushing it all through.

1 Like

Nice so you did not use a pre mix you mixed it yourself? I think this has additives allready I should run it straight?

https://smile.amazon.com/gp/product/B07LFMY2V8 is also an option

it doesn’t do anything about freezing, but it does try to keep all the icky growth out

1 Like

Guess you can pick a color lol…

I found some similar dyes for PC water cooling and asked the vender about using it, I got a reply:
“So the coolant that we sell for water cooling is probably not what you want to use inside of that type of setup. The distilled water is probably your best option and the coolant / antifreeze that they suggest you add would most likely be for the anti-corrosive properties… It’s also likely that they suggest it for lower temperature applications. If there’s a mix of metals, like copper and aluminum in the same loop you’ll have some major issues.”

I am not a chemist, but I think he just told me not to use it haha…

there’s two types for PC water cooling. the other type is indeed not good for multiple metals

1 Like

The other issue I ran into was that additive is 15 dollars, enough for 1 liter of liquid. I have a 2.3 gallon reservoir plus about 40 feet of hose.

Well then gold it is, obviously :wink:

I mixed my own as I already had some RO water.

I have a 20 Litre ‘reservoir’ with my circulation pump in it, this is an old water container which I used to use on my fish tank. I use RO (de-ionized, distilled) water from the local fish tank shop as my cheap non-chalky water supply. I just add some regular automotive anti-freeze and mix with the RO water. My use of RO is why I need the anti-green-slime additives too.

In a vehicle cooling system I think the running temps do quite a lot of the work to kill the green slime that would otherwise grow, spindles shouldn’t run that hot.

And yep, at least one person here has warned about putting copper radiators in the same loop without the correct inhibitor or sacrificial anode.

1 Like

I can attach one of those silver bullet inserts into a flow meter no problem they have G1/4 fittings.
So the consensus is this colored import antifreeze is ok?
I use this antifreeze straight? Do I add additives to antifreeze? Do I need a sacrificial anode? Hah… always something else right! lol… I imagine the Chiller is designed for coolant…
Light Object 1600W Chiller

I still haven’t found any authoritative info on this.

Mechatron says;
“When dimensioning the cooling system it must be ensured that the maximum temperature at the outlet of the motor spindle does not exceed 30°C.
The coolant circuit must have a temperature display and a flow indicator in case that no direct temperature control and automatic shutdown is applied (see 5.3). In case no direct temperature control is applied, the temperature and flow has to be checked every 15 minutes by the user. If the temperature exceeds 30°C or the flow indicator doesn’t indicate any coolant flow, the motor spindle has to be stopped immediately and the system has to be checked for the reason of the fault.
The coolant liquid must be a special coolant which ensures protection of corrosion, does not dissolve rubber gaskets and has a low electrical conductance. Only use coolant which is approved by the manufacturer.”

They also sell special spindle coolant

There are other sources of special CNC spindle coolant;

But the key components appear to be corrosion inhibitors for the metals in play in that system and some sort of anti-fungal.

One very common element is to not use tap water but demineralised of some sort.

I only have the steel of the spindle internals and the pump rotor shaft as metal in my circuit everything else is plastic so I don’t have to worry about copper vs. steel or other complex processes to inhibit, it hasn’t failed yet…

1 Like

Thank you for the help Liam, I appreciate it very much.

1 Like

NP, just sorry it’s not more helpful, I did the same sort of search when it came to filling my system up, Luke and others told me what they were doing and I mostly figured “what worked for them…”

1 Like

I have been endlessly searching and I found a post where one machinist back in 09’ stated the spindle should be within 2 degrees of ambient temperature to avoid condensation and to keep a steady temperature to avoid different clearances due to expansion.
This seems like good advice to me.

1 Like

I guess the 1600W seems to be on point with maintaining temperature. I think this is saying it can maintain a temperature to .5 degree C which I think is kinda like Fahrenheit yes? Let me grab my Abacus and check… Light Object is an American company? Why are they listing specs in Celsius lol… Let me try using the inches to mm formula on this…
I would like to loop 4 or 5 spindles through this thing lol… Am I dreaming??

-Light Object 1600 W Chiller: This is our latest design with PID temperature controller. The LO-1600W chiller is an ideal candidate for a laser machine running a laser tube with a power range from 130W to 180W. It can handle two 130W tubes that are running simultaneously!


  • 20% cooling performance improvement
  • Integrated temperature controller installed
  • Better temperature control +/- 0.5’C
1 Like

LightObject imports stuff.

For a thermal transfer fluid/antifreeze, check out Dowtherm SR1. It’s what we use in the fiber laser.

I’d say that the requirements for a laser are probably quite a bit tighter than for a GPenny or similar Chinese commodity spindle.

The runouts and clearances on these cheap VFD spindles just aren’t that tight to start with and the Shapeoko machine precision is probably the limiting factor here.

Avoiding coolant temps below the local dew point is a good move to avoid condensate on the coolant lines or spindles, water supply around 30C also seems reasonable. If we were running at the full 2.2kW power output then I’d really worry, but we’re not, I hardly ever get my spindle over 200W of power.

As for running several machines, are you going to give them all their own pump? Otherwise the effective head through them all will be huge.

1 Like

This topic was automatically closed after 30 days. New replies are no longer allowed.