Horror Story Using Water-Based Coolant

[Nelson]

From another forum:
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"I was using Rustlick Synkool mixed with water as a cooant in my milling machine and all was going well,
-- Tools lasted longer,
-- parts and tools stayed cool,
-- splatter was controllable
-- clean up was easier
-- nothing rusted
-- no stinky coolant
-- Set up tools (clamps, bolts, parallels etc.) cleaned off easily

There were a couple of annomalies:
-- surfaces seemed to have a slight waxy feeling to them
-- sliding surfaces, even oiled ones like the ways, had a "break away" resistance the first time they were moved the next day.

AND THEN, when I least expected it. It turned on me !

-- A couple of weeks ago I noticed a bunch of speckles on a ground surface on the top of my vise. I scratched at them and they appeared to be black waxy lumps but they cam off easily enough
-- The next time I encountered the black waxy lumps they appeared on the far end of the table and on the ground surface of the rotary table. When i went to clean these off there was surface discoloration under the lumps, No pitting, more like a faint grey stain.
-- Then I found lumps under the vise base and under the rotary table base where they sit on the milling table and these looked more like rust but cleaned off fairly easily but did leave more discoloring.
-- I found lumps were appearing more and faster and even found some on a chuck I had not had on the mill for several weeks and was clean when I took it off.
-- Now the lumps clearly appeared to be rust and leaving marks on the surface but no pitting and the lumps would appear overnight
-- I also started to find some (not much) of the same on my parallels

I decided to clean up the machine thoroughly and in the process found that the dove tail on the ram between the turret and the milling head was orange! During the clean up, I found that apparantly water was evaporating from the sump, rising through the column and condensing on the bottom ofthe ram and causing rust. There were lumps of orange rust on the bottom of the dovetail (fortunately that is not a bearing surface. and what was on the bearing surface came off easily before I generously greased the whole thing. While cleaning up and inspecting the mill, I emptied, cleaned, flushed and dried out the sump and flood coolant system.

I also use a separate batch of the same cooant at a different concentration on my tool grinder as it prevents rust on the tool rest tables at both ends. I now was finding a milder case of the same phenomenon there.

Earlier in my experience I would have said the this syncool was the best thing since sliced bread, as I used it successfully for several months, but something has now gone wrong.

Contact with the manufacturer suggested several possible sources of the problem
A. The hard water I was using may be the #1 culprit (our water is very hard)
B. An accumulation of iron particulates in the coolant might be forming rust on top of the machine parts and then eating into the parts.
C. We have experienced rising relative humidity in the weather recently and now very high humidity

I should mention that:
-- I had to add water from time to time because the water would evaporate out of the coolant, but a salesman handling the Rustlick product said that this was normal.
-- I had to keep the concentration within bounds and do not have a refractometer to measure concentration but the range was quite wide, (i.e. as strong as 1 to 10 or as dilute as 1 to 25)
-- I was controlling tramp oil by intermittent skimming but never had complete oil cover in the sump.

I do not want to give up on flood coolant because there was so much it did for me in solving problems. So what I would like to hear about from the more experienced heads here is.
-- Are there causes besides A,B, & C that I should be looking at ???
-- Has anyone seen this sort of thing coming from hard water from a chlorinated fluoridated municipal supply
-- are accumulations of particulates in the coolant a problem that could cause this and if so how would one deal with this?
-- Is there some other water based coolant I should use that
------- also has very good resistance to stinking up the shop (in the house)
------- would give me better resistance to rusting problems
------- not break the bank to obtain. (i.e. not too expensive per gallon, and availalble in smaller quantities such as 5 gallons at the very most)

-- Is there a non water based coolant I could use that would serve better considering my situation?

And of course anything else beneficial you can offer me to solve the problem. That includes anything that you have seen in the way of similar problems and problems I have not encountered yet.

If I should be so lucky, that the problem is only the hard water, my solution would be to use a plastic external sump and demineralized water That would solve the problem of rusting on the bottom of the ram. I will probably have to do this for any water based coolant unless there is one that suppresses evaporation from the sump. Blocking the top of the interior of the column just does not appear to be practical by any means. I am surprised the sump was set up this way."
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What is everyone's experience with these water-based coolants for home shops?

Thanks,



Nelson

 

[cyrusb]

Water based coolants are good if you are General Motors with the machines in continual use. But for the occasional use hobbyist they do just what you are seeing. They cannot be allowed to dry. Not only do they leave a soapy mess, but the water rusts your iron. Since I'm a "Hobbyist" I just adjust my cutting speed to not produce smoke with conventional oil. If I must take big hot cuts I use a Cool Mist unit that when adjusted right leaves nothing behind. But really, since I am not "on the clock", 99.9% of the time I just use some motor oil and an acid brush. Incidentally, the cool mist unit is great for big band saw jobs.

 

[Pacer]

EXACTLY what cyrusb said... even my machinist friend/mentor rarely uses any coolant even then its a mister type. I just do like cyrus and slow things down..

 

[Highpower]

On the mill and the lathe I only use coolant by hand via a squirt bottle, and even then it gets everywhere. I don't push my machines hard by any stretch, but things do get warm after awhile and I can't afford to burn up tooling on my budget.

The only thing using flood coolant in my man cave is the band saw, and haven't had any problems with that - yet.

I've tried using a mist cooler on the drill press and ended up fogging myself out of the house. It now collects dust. :
After that I bought a flood system for it, but never installed it. Since getting the mill, the drill press doesn't see a lot of use any more.

 

[pdentrem]

We have a Lansing cylindical grinder at the shop. The coolant can get rancid after awhile. Even using the antibact pucks! Our water is city treated Lake Erie water. Ph values are important but you need a tester like used for pools or refracting ph tester maybe. Use distilled water?

Another problem we ran into while grinding our finish rolls for our Stanat rolling machines was the surface finish. Turns out that the filtering was not fine enough. I added a standard remote oil filter just before the spray head, like you find on trucks and use standard PH-8 oil fliters and they are changed out on just about every use of the grinder. The filter is stopping the return of metal filings back to the work. Made a major difference on surface finish and you can sure tell when the filter gets loaded as the coolant flow drops off remarkably, be sure to buy filters that do not have bypass valves builtin.
I have suggested using a remote storage tank that is sealed to the shop. This will help as noted by dalee.

On the stamping presses, we have to wipe down the work tables and remove the jigs etc all the time as the surfaces will end up just like you are seeing on yours!

 

[NightWing]

Years ago when I had my machine shop, We used a brand name water based synthetic coolant in our MAZAK CNC turning machines. The coolant did an excellent job but after a time, there was a build up on top of the coolant tank that was like a sheet of rubber. It was really gross and the girls (all employees were female) hated it when i said we needed to pull the tanks and clean out the rubber.

The coolant manufacturer and the dealer were both cooperative but had really not seen this before. A sample of the rubber sheet was sent to a lab and it was confirmed that it was a sheet of bacteria. It was allegedly formed from the tramp oil in the sump (hard not to have when the injected ball screw lube was not reclaimed) that would seal off oxygen in the coolant. The bacteria would start to grow and build up a coating that was an eighth of an inch thick. It was gross to handle and would tear apart when you tried to pick it up. Another source of tramp oil was the oils present on bar stock which would be washed off during machining.

I bought an oil skimmer to skim the tank and a refractometer to check the coolant concentration. I also bought some "bugs" which were good bacteria to eat the bad stuff. They were administered weekly and did help, but we never were rubber free.

On the other hand, the screw machines used cutting oil and we never had a bacteria problem.

As an aside, it cost about $60 for a 5 gallon pail of coolant concentrate and $185 a drum to dispose of the coolant/water mixture once it had been in a machine. It was biodegradable in the bucket but once mixed and used in a machine tool, it became regulated waste. That was actually a decent price because the reclaimer was able to extract a little oil from it and he gave us a break.

 

[ddmunroe]

Water based coolant was used in my milling grinder, I had some time ago.
After seeing the mixture evaporate and grow that bacteria. I then started draining it between uses and storing it under vacuum. I don;t have that machine anymore. I won;t go water based again unless an everyday use.
These days for milling and lathe I use the RTD cutting oil on a brush. The smoke crated should be extracted away from yourself in this case. Buy a hyrodoponic fan with some flexible ducting, these are whisper quiet and can run 24hrs/day.
dd)

 

[samthedog]

I only use cutting oil. The cost of the cutting tools pale in comparison to the cost and headache of a rusting vintage machine and accessories.

I have a coolant pump on my metal bandsaw too but just squirt a little cutting oil during cutting because I can't be bothered with the mess and the rust.

Paul.

 

[jatt]

Getting some tarnishing on my bandsaw from the water based coolant, but havent seen anything growing thus far in the coolant tank. Definitely time to change it over I will admit.

wrt to the mill. Seem to have more trouble with condensation on the bare metal surfaces this time of year then a bit of tarnishing from water based coolant. Having said this tho, I do wipe off any coolant that I see sitting on any surfaces. Only use coolant from a spray bottle on the mill, mainly cause I didnt want to go to the expense and stuffing around with doing so. Not practical to setup both units from one tank ( they're 9 metres from each other).

Diluting my water based with tank water. Ratio, whatever my free pouring produces. Top up with water, especially in summer when get a fair bit of evaporation. If it starts looking a bit weak, add more coolant.

Times I use straight oil just use a bit of lite grade sewing machine stuff. Fact I got plenty lying around obviously helps.

 

[Ebel440]

I work with cnc mills and we use water based coolant. The concentration needs to be correct or you will get rust better to thick then thin. Also as others said the machines need to run regularly even if we are not using a machine it will be turned on and run through a simple program with the coolant running. I personally would not use it in a home shop due to the coolant growing bacteria and stinking. We drain our sumps and scrape out the bacteria at least once a year and its one of the nastiest jobs iv ever had to do