Plumbing a water-cooled spindle.

[Kitwn]

For my new 2.2kW water-cooled spindle I bought a pond pump and 10 metres of 5mm i/d PVC pipe from my local Home Hardware. A quick test gave a flow rate (with no head) of only 30 l/hour. Another test with only 250mm of the pipe gave 4 times that rate. This showed that it's the length of pipe that reduces the rate, not just the fact of choking the pump outlet to 5mm. A return trip to Home Hardware found that the 8mm size pipe will just accept the 5mm size inside it so I bought 10 metres of that. This size will also just fit into my new 70x15mm Banggood drag chains. A bit of PVC pipe glue plus some heat-shrink sleeving for good measure created a couple of stubs of 5mm pipe to connect to the spindle. The overall flow rate through the spindle is now 60l/hour.
Another advantage for anyone else who follows this plan is that the pump I bought came with a plastic outlet barb the right size for the 8mm pipe whereas I'd had to find a brass fitting and modify it in my lathe for the 5mm size.

Kit

PS What do you use to prevent corrosion and algal growth in your cooling water? I'm using distilled water and wanted to add some car anti-freeze (ha-ha, the lowest temperature ever recorded where I live is 7.6C) but was advised not to as we didn't know exactly what metals were in the spindle and it might have an adverse reaction.

[Chaz]

For my new 2.2kW water-cooled spindle I bought a pond pump and 10 metres of 5mm i/d PVC pipe from my local Home Hardware. A quick test gave a flow rate (with no head) of only 30 l/hour. Another test with only 250mm of the pipe gave 4 times that rate. This showed that it's the length of pipe that reduces the rate, not just the fact of choking the pump outlet to 5mm. A return trip to Home Hardware found that the 8mm size pipe will just accept the 5mm size inside it so I bought 10 metres of that. This size will also just fit into my new 70x15mm Banggood drag chains. A bit of PVC pipe glue plus some heat-shrink sleeving for good measure created a couple of stubs of 5mm pipe to connect to the spindle. The overall flow rate through the spindle is now 60l/hour.
Another advantage for anyone else who follows this plan is that the pump I bought came with a plastic outlet barb the right size for the 8mm pipe whereas I'd had to find a brass fitting and modify it in my lathe for the 5mm size.

Kit

PS What do you use to prevent corrosion and algal growth in your cooling water? I'm using distilled water and wanted to add some car anti-freeze (ha-ha, the lowest temperature ever recorded where I live is 7.6C) but was advised not to as we didn't know exactly what metals were in the spindle and it might have an adverse reaction.

I used antifreeze. Didnt run my system for long but that will work.

[cropwell]

Glycol based Antifreeze is normally loaded with corrosion inhibitors, so I would reckon it to be OK. I don't have that problem with my Kress

[Kitwn]

Thanks cropwell,
I went water cooled partly because of the high ambient temperatures here (Exmouth, WA) and also the noise. My previous spindle was a Chinese clone of a Makita trimmer/router which screamed the place down as soon as it started and burnt out due to overheating. The new spindle makes as much noise as the pond pump before it starts cutting.

I was a bit surprised by what the salesmant at Auto-Pro said about anti-freeze but I know he's no idiot and thought a few other opinions would be worth getting.

Kit

[cropwell]

Here matey. have a look at this - https://en.wikipedia.org/wiki/Antifreeze

[Kitwn]

Here matey. have a look at this - https://en.wikipedia.org/wiki/Antifreeze

Reminds me of Time Team..."'ere Tony, come and 'ave a look at this!"

Now I'm even more confused, but it shows there's more to this than pouring in some green stuff.

Kit

[cropwell]

Now I'm even more confused, but it shows there's more to this than pouring in some green stuff.

Kit

Good grief man, you can't use the green stuff, Gotta be blue or red G13 at least. Failing that, how about VW Beetle antifreeze

Personally, I gave it up when they stopped the methanol based stuff.

Cheers !

Rob-T

[Kitwn]

Well it used to be green! That's only the fluorescein dye anyway. I Think the last time I actually bought anti-freeze in a shop Mrs Thatcher was still PM. I'd had enough of grovelling about under cars at the side of the road by then and vowed that as soon as I could afford it I was going to pay someone else to service my car. I would, of course, now purchase the latest safety approved product from a reputable Australian supplier.

Kit

[magicniner]

Any good quality Ethylene Glycol based anti-freeze has corrosion inhibitors which will work well in a system which includes Iron, Steel, Aluminium, and/or Brass, use De-Ionised water too to avoid any chance of impurities building up inside the spindle.

[Kitwn]

I'm afraid Ethylene Glycol is out due the risk of poisoning the dogs if I get a leak and they lick it up. I'm tempted but my wife would never forgive me! The Proylene Glycol version is OK so I'm going to head for our local Auto-Pro and read the labels very carefully.

I obviously don't need the anti-freeze/anti-boiling properties of the stuff but some corosion inhibiters might be nice. I am also concerned about algae growing in the water. It doesn't get hot enough to kill the stuff but the ambient temperture here is perfect for it. If I don't find a suitable anti-freeze I might just go for adding a little chlorine based bleach (NOT the 'oxygen' stuff). A little further reading on Wikipedia sugests that a weak solution of 200ppm Sodium Hypochlorite will be strong enough for bug killing but won't attack the metals. Standard household bleach is about 5% (50,000ppm) so a couple of tablespoons of bleach in 10l of distilled water should do the trick.

Thanks for all the comments from everyone so far, this has prompted some interesting reading.

Kit