Plumbing a water-cooled spindle.

[magicniner]

If all you are looking at is corrosion inhibition, how about something like Fernox - used in central heating. I haven't researched it, this is just tossing an idea into the pot.

An excellent suggestion, used with DI water that should cover all the bases, don't use bleach, if you need an anti-biological it needs to be PH neutral, but you could run your coolant through a pond/aquarium UV unit on it's return to the tank to keep the biological load to a minimum or you could have a submersible UV unit in the tank.

[Kitwn]

Some good ideas there, thanks everyone. Re using bleach: the body of the spindle is aluminium so there is a risk there, though Wikipedia says it'a not corrosive at 200ppm hence the limit of concentration there. At the moment I'm still using plain old distilled water with no signs of an ominous green tinge.

Re the use of switches, thermostats etc for turning pumps on and of: my 240v pond pump is quieter than the VFD fan so I simply have it on the same mains supply switch. If the VFD is on, the pump is on. After a long cut yesterday for levelling the machine bed I found the tool and spindle shaft quite warm. I turned the pump off and the lower body of the spindle warmed up noticably so I turned the pump back on and it cooled almost immediately. This makes me more certain (as I said in the other recent thread about switching pumps on and off) that leaving the cooling on continuously during a working session will help cool the spindle faster after one cut and so reduce the starting temperature for the next. And it's simpler to implement. KISS!

Kit

[cropwell]

Again, an off the wall suggestion, to inhibit algal growth how about a phenol based disinfectant, like Jeyes Fluid ? I do not know the pH properties of it though. You certainly would not need much.

[Kitwn]

Something else to consider, I'll look into it.

Having at long last got my machine into a state I'm hoping (with everything crossed) is going to prove workable and reliable for a reasonable period of time, I've finally tidied up, taken a photograph and given myself an avatar. The room is exactly 2 metres wide so the dust extractor is mounted high on the wall with the water tank underneath. Underneath that is a trolley with the controller (breakout board, stepper drivers and PSU in an old PC box) plus LinuxCNC computer. Cutting area is 940 x 640 mm.

Maybe we need a thread based on "what did you make with your CNC machine today?" There's no end of stuff on this website about the machines themselves but precious litle about what we all actually do with them!

Kit

[cropwell]

Just a word of caution - phenol may attack and embrittle any plastic or rubber it comes into contact with.

My central heating header tank had a pint of cheap engine oil floating on top of the water to exclude oxygen. It worked well as it just stayed in the tank. Any oxygen in the water was soon boiled out.

[routercnc]

Late to the thread but I’ve been using pc water cooling fluid for years and works fine. Lots on eBay such as EK-cryofuel.
Claim they are non toxic, don’t corrode wide range of metals, have anti fungicide etc.

[cropwell]

Late to the thread but I’ve been using pc water cooling fluid for years and works fine. Lots on eBay such as EK-cryofuel.
Claim they are non toxic, don’t corrode wide range of metals, have anti fungicide etc.

Of course ! Why did I not think of that, when most of the components I have for spindle cooling are out of a water cooled computer.

[Kitwn]

Of course ! Why did I not think of that, when most of the components I have for spindle cooling are out of a water cooled computer.

Of course ! Why did I not think of that... as well! Though I've never water cooled a computer and I'm not using anything as swanky as a radiator in my system. Good idea.

Kit