# Coolant and rust



## 3strucking (Apr 16, 2017)

i have not been using coolant on my lathe because I am worried about rust. My shop is not climate controlled and humidity is always high in GA. Is there a way to run coolant without rusting becoming a problem in my situation?


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## cathead (Apr 16, 2017)

Use oil for coolant possibly?


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## Terrywerm (Apr 16, 2017)

I used to work in a shop that had a 15" Monarch lathe, which was a little piece of heaven, I might add. It had a built in coolant system and we just ran cutting oil in it. Never got rancid and kept everything oiled up nice, too.

It wasn't the ideal coolant for aluminum or anything like that, so we'd just leave the coolant pump shut off when working with non-ferrous materials.


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## 12bolts (Apr 17, 2017)

Depending on the work you are doing it may or may not be necessary. Most soluble oils for flood coolant incorporate rust inhibitors. But for a lot of hobby use direct application of cutting fluids is also effective and appropriate.

Cheers Phil


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## 3strucking (Apr 17, 2017)

I have been using direct application even though my lathe has a coolant tank and pump. I've  been using tap magic on ferrous metals but it smokes like a freight train.


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## British Steel (Apr 17, 2017)

I'm with Terry, cutting oil in the coolant tank for when I need it - before it reached my hands the gasket sealing the top of my Holbrook's (sealed, oil-bath) QCGB had let go and water-based coolant got in and wrecked the unobtainium taper-roller bearings inside... Some Effort Required to clean up the gears and replace with imperial but available taper-rollers in top-hat bushes.. 

NO water-based anything is getting near it now.

Dave H. (the other one)


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## Rustrp (Apr 17, 2017)

rightway1974 said:


> i have not been using coolant on my lathe because I am worried about rust. My shop is not climate controlled and humidity is always high in GA. Is there a way to run coolant without rusting becoming a problem in my situation?



Just replace the word "coolant" with **lubricant** and keep turning. Apply it manually as has already been stated to whatever you're working on and all is well.

I should ask; Do you want to run coolant and why?


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## Rustrp (Apr 17, 2017)

rightway1974 said:


> I have been using direct application even though my lathe has a coolant tank and pump. I've  been using tap magic on ferrous metals but it smokes like a freight train.


Just add a small exhaust system behind the lathe.


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## markba633csi (Apr 17, 2017)

I like that song- Neil Young isn't it?


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## ch2co (Apr 17, 2017)

rightway1974 said:


> I have been using direct application even though my lathe has a coolant tank and pump. I've  been using tap magic on ferrous metals but it smokes like a freight train.



I'm not sure where I got this idea, but it wasn't originally mine, to use Canola oil for a lubricant on ferrous metals.  I mostly deal with aluminum and brass, but
when steel comes up, I've just been using the Canola oil from our kitchen. Squirt bottle or brush depending on what I'm doing. I compared it to every oil I had
in the shop, and its smoke point and odor are far superior and it seems to be a good lubricant to boot. Use it on the lathe and the mill. Mind you, my machines
are toys to some of you guys.


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## Silverbullet (Apr 17, 2017)

I seem to have an ample supply of used hydraulic oil. I've been using it for cutting fluid . I even use it mixed with acetone for rusty part clean up. I get it free so why not.


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## Reeltor (Apr 17, 2017)

On the lathe I use a brush or spray bottle of cutting oil (Oatey?) from the plumbing department at Home Depot or Lowes.  On the mill, I sometimes use flood coolant, KoolMist 77.  I mix it just a tad richer than the instructions.  I've only found rust under the vise and dividing head, after they'd been in one place for months.  The rust just wipes off with a shop rag.


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## brasssmanget (Apr 17, 2017)

I used to use a coolant/cutting fluid sold by that mail order place that is now MSC (?). Enco was it??

I don't see it listed in the catalog anymore. It worked pretty well and did not produce rust if left unattended for a time....


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## dulltool17 (Apr 17, 2017)

50/50 Automatic Transmission Fluid/WD-40
Works wonders


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## Rockytime (Apr 17, 2017)

I use ATF foe everything. Ferris or non.


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## Tozguy (Apr 17, 2017)

Unless you need high production levels there is no need of coolant for most hobbyists. Control speeds, feeds and d.o.c. to keep chips and tools from getting too hot. Water based coolants are more trouble than they are worth when you only really need a lubricant. If cooling is actually necessary when cutting dry then consider air cooling first. If using cutting oil flooding will cool things some. ATF would be my first choice.


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## ch2co (Apr 17, 2017)

Tozguy

Doesn't a "coolant" also lubricate?? It sure makes cutting easier in many cases.


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## Tozguy (Apr 17, 2017)

Yes the additives do lubricate a bit among other things but water does the cooling not the lubricating. If you only need a lubricant, oil is better than a water coolant with less of a hassle.


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## jbolt (Apr 18, 2017)

I can't answer you specific question about high humidity since we don't have that here. As far as coolants go, the most user and machine friendly coolant I have found for hobby use is KoolRite 2290. Non-irritating, almost no odor and no rust issues. I use this on my CNC mill. I change it once a year to get rid of the tramp oils. I've never had it go rancid. My tank has a few unsealed openings and I have a small aquarium pump on a timer that runs 15 minutes a day to keep it aerated. 

If you do use coolant on the lathe it is always good practice to wipe and excess residue off the ways and re-oil after use. Having good way wipers helps keep the coolant out from between the sliding surfaces but it will find its way in so keep those well lubricated and use a way oil with rust inhibitors.

I have a coolant system on my lathe but have yet to have a job that would justify using it. If brushing cannot supply the needed amount for lubricant or I if want to use coolant I will use a spray bottle or applicator bottle.


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## scwhite (Apr 18, 2017)

terrywerm said:


> I used to work in a shop that had a 15" Monarch lathe, which was a little piece of heaven, I might add. It had a built in coolant system and we just ran cutting oil in it. Never got rancid and kept everything oiled up nice, too.
> 
> It wasn't the ideal coolant for aluminum or anything like that, so we'd just leave the coolant pump shut off when working with non-ferrous materials.


I have worked in several machine shops that just 
Run ridged cutting oil in everything but the grinders 
    It seamed to be the perfect cutting oil 
You would get a lot of smoke but we didn't have a rust problem


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## NortonDommi (Apr 19, 2017)

Hello,
           Silverbullet, how do you find the hydrualic oil as a cutting fluid? I've just been offered some 46 at a good price,(about 1/3 of the cutting oil I like), might be a bit heavy but I hate the cleanup after using soluble oil.
  - Barry.


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## benmychree (Apr 22, 2017)

I had a 4,000 square foot machine shop for nearly 40 years, sold it and retired; rust was not a problem in the good old days when coolants had amines in them to prevent breakdown and consequent rusting. The scare over nitrosamines forced the removal of amines;  after reformulating, rust was a big problem, especially on machines that were used infrequently, where tramp oil would prevent the coolant from being aerated and breakdown occurred .  I had a large surface grinder where this was a regular event, and I did try bubbling air into the sump without much success.  I have a power hacksaw in my home shop where rust is a big problem, it cements the fine chips into a solid mass that takes a hammer and chisel to break up.  My plan with it is to use a 50/50 mixture of cutting oil and kerosene, as recommended by the maker of the Marvel power hacksaw that is in my old shop. The kerosene transmits heat better than oil, the cut off parts are quite noticeably cooler than when the oil is concentrated.  I plan to also use this on my Brown & Sharpe universal mill at home.  On most of my machines at home I use TapFree in a tuna can with a brush, in my lathe, a Regal Leblond 19", I use a modern coolant concentrate that does not seem to have so much potential for rust as the previous ones that I have tried; oil, when used for roughing makes way too much smoke, which I imagine does not do good for our lungs.


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## 3strucking (Apr 22, 2017)

i dont use my machines daily, thats why im worried about rust


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## scwhite (Apr 22, 2017)

benmychree said:


> I had a 4,000 square foot machine shop for nearly 40 years, sold it and retired; rust was not a problem in the good old days when coolants had amines in them to prevent breakdown and consequent rusting. The scare over nitrosamines forced the removal of amines;  after reformulating, rust was a big problem, especially on machines that were used infrequently, where tramp oil would prevent the coolant from being aerated and breakdown occurred .  I had a large surface grinder where this was a regular event, and I did try bubbling air into the sump without much success.  I have a power hacksaw in my home shop where rust is a big problem, it cements the fine chips into a solid mass that takes a hammer and chisel to break up.  My plan with it is to use a 50/50 mixture of cutting oil and kerosene, as recommended by the maker of the Marvel power hacksaw that is in my old shop. The kerosene transmits heat better than oil, the cut off parts are quite noticeably cooler than when the oil is concentrated.  I plan to also use this on my Brown & Sharpe universal mill at home.  On most of my machines at home I use TapFree in a tuna can with a brush, in my lathe, a Regal Leblond 19", I use a modern coolant concentrate that does not seem to have so much potential for rust as the previous ones that I have tried; oil, when used for roughing makes way too much smoke, which I imagine does not do good for our lungs.


I like that mixture 50/50 cutting oil and Kerosene
   I might set my new horizontal bandsaw up with that mixture .
   I hope my cheap coolant pump will run it good


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## th62 (Apr 22, 2017)

I use water soluble oil as a coolant, just mix it with a little less water and rust is not a problem


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## NortonDommi (Apr 23, 2017)

Hello,
          benmychree, like scwhite, I like the Kero mix idea. I've got the same problem on my bandsaw as well so have to clean it after every use, a real pain late at night. I also have the problem of the pump impellor  sticking if I don't use it for a few weeks, more hassle when you just want to caut a small piece.
  I use 50/50 Kero and Dextron III ATF as a penetrating fluid and it outperforms every thing else I have tried inclueding Kroil. Just bought a pail of stocktake clearance ISO 46 hydrualic oil,(same weight as Dextron), so will experiment with that as a mixer.
  Thanks for sharing your experience.

  - Barry.


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## scwhite (Apr 23, 2017)

NortonDommi said:


> Hello,
> benmychree, like scwhite, I like the Kero mix idea. I've got the same problem on my bandsaw as well so have to clean it after every use, a real pain late at night. I also have the problem of the pump impellor  sticking if I don't use it for a few weeks, more hassle when you just want to caut a small piece.
> I use 50/50 Kero and Dextron III ATF as a penetrating fluid and it outperforms every thing else I have tried inclueding Kroil. Just bought a pail of stocktake clearance ISO 46 hydrualic oil,(same weight as Dextron), so will experiment with that as a mixer.
> Thanks for sharing your experience.
> ...


I went and looked a used Clausing   Horizontal bandsaw . It was so Gumed up with dry gummy waxy
coolent nothing worked right . All the blade rollers was locked up . Pump everything it was bad the worst I have ever seen .
    I left it with them and went to Grizzly and bought
This new G4030


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## scwhite (Apr 23, 2017)

Rustrp said:


> Just replace the word "coolant" with **lubricant** and keep turning. Apply it manually as has already been stated to whatever you're working on and all is well.
> 
> I should ask; Do you want to run coolant and why?


I like manually applying cutting oil with a small
Brush most of the time .
     But I have a  horizontal mill and I plane on running cutting oil onto my expensive cutters .
    Some of those cutters are $500.
         And you will need a good flow of oil on it
And it will cut and preform much better useing
Cutting oil .
        I am planning on using  that 50/50 mixture
Of  rigid cutting oil and  kerosene on it like Benmychree stated earlier . And my
 Horizontal bandsaw . I think it would wash out the chips and keep the blade cooler & cut smoother


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## NortonDommi (Apr 29, 2017)

Well I mixed up some ISO 46 hydrualic oil and Kero in a 50/50 mix yesterday to try out as acutting oil,( a mix of silverbullet and benmychree's ideas), and as I had been in a discussion about homemade penertrating oils decided to compare to my old standby of 50/50 Kero/ATF, it was not as good. I had a bottle of Morey's Heavy Duty Oil Stabiliser out and decided to see how that would mix so added a few drops. Big difference which started a bit more experimentation. Ended up with a final mix of equal parts by volume  Kerosene, ATF and hydrualic ISO 46 mixed then 6% Morey's added. somehow this works better than anything I have tried yet.
  I digress from the matter at hand just thought some may be interested and as soon as I finish off the job at hand,(cast iron), I will try the 50/50 Kero and hydrualic oil for a cutting fluid as it is cheap and  I have the ingrediants. Hopefully easy cutting, chip clearance and an end to rust!


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## malmac (May 10, 2018)

For many years on my mill I have used a mix of cutting oil and diesel. Works OK and has no problems with rust - I guess Kero or Diesel, they really are there just to thin the oil (I suspect). I have tried the water soluble coolant on my lathe and I just find it gets under the cross slide and is such a pain I have drained it all out and am considering using the cutting oil and diesel mix - so I don't end up with the soupy white mix the water soluble stuff seems to create. I did mix it strong so have not had a problem with rust BUT I don't trust it - and because I don't work ever day of the year - leaving it sitting has been a problem. Other than smoke if you cut to deep and hard, what other problems exist with the cutting oil / diesel mix?

Mal


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## rrjohnso2000 (May 10, 2018)

For you guys running water soluble oil/coolents be careful with the concentration you run. Often they are designed to work only within a percent range of mixture, example only 25-30%. That window keeps everything in solution. Outside of that it starts to separate and that causes problems. The separation can occur immediately, within minutes, or longer. Use what works for you but start with the directions. 

From a once upon a time lubricants and violent chemist


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## Charles Spencer (May 10, 2018)

I don't know what size machines you are running.  Most of my machines are small:  9" lathes, benchtop mill, Chinese mill-drill, upright bandsaw, power hacksaw, and drill presses.  I've always just used cutting oil, either brushed on from a magnetic base bottle or spritzed on with a spray bottle.  If it smokes then I turn a fan on it.


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