View Full Version : Rancid Coolant

02-08-2002, 07:07 PM
Just thought I would add my two cents worth..Coolant goes rancid very quick when doing cast iron..it even goes rancid over time...For those who don't know, try adding very fine shavings of copper into the coolant..I usually mill very fine cuts in copper to produce fine shavings..there is a chemical reaction with the copper that prolongs the longevity of the coolant...I have tried it and it works..I don't know exactly why..Also try getting a bubbler (like the ones you have in a fish tank) put it in your coolant tank and turn it on just enough to make a couple of bubbles a minute..I don't know why that works but believe me it does...keep your bubbler on at all times...It introduces air in the coolant or something..I used to use trim-sol...hate it...I then switched to blauser...hated it...now i use Valcool....like it....just something i learned over the years....


02-08-2002, 11:01 PM

Use of distilled demineralized water makes the best mix with regular or synthetic fluids. Good tip about the copper.


02-09-2002, 04:34 AM
I'll try it, hope it works.

Doall surface grinder at work doesn't get used much, it sure gets rank. We pour some pine-sol in it, helps some, as does just letting coolant run for a while, one of us needs to find a cast off fish tank pump. Coolant gets to smelling like a fish died in it, if we give that fish some air, maybe he'll live longer.

Many thanks if it works.

[This message has been edited by halfnut (edited 02-09-2002).]

02-09-2002, 06:31 AM
Bubbling air through the coolant will disolve oxygen into it which will inhibit the growth of those smelly anaerobic bacteria. At least I'll bet that's what's happening. Good suggestion. Maybe the copper has a similar effect.

02-09-2002, 02:33 PM
I'm sure that copper will kill off some bacteria, I use it every once in a while to treat some of my fish. Works pretty well too. Ony bad part is that when I first used it nobody told me it would also kill of snails. oops...

02-09-2002, 11:31 PM
Killed yer snails? Butter 'em up and have a snack! Yuummmm!

You can buy tablets to throw in the sump. Getting the tramp oils out of the coolant greatly extends the life of the coolant.

Sythetic coolants are not nearly as much trouble as "suds".


02-09-2002, 11:36 PM
Read somewhere that bubbling ozone thru the stuff kills any living thing in the oil. On the plus side, the by products of this reaction is pure oxygen. As O3 (ozone) reacts with and kills living bacteria, it is converted to O2. Sounds friendly enough to me. So where does one buy a can of pressurized ozone???

[This message has been edited by bdarin (edited 02-09-2002).]

02-10-2002, 07:53 AM
I had a chicken once that gave ozone eggs, was what you call an ozone layer, might try farm supply for more.

02-10-2002, 10:27 AM
Oxygen would rather be O2, that third O is just dangling there looking for something to react with. That's why ozone such a powerful oxydizer, and it's also not very stable. You need to generate it at point of use. In principle it's easy to do with an elecrical discharge. I don't know what the practical difficulties are, corrosion of the device itself is probably one. Its reactivity means there are health risks as well, probably best not to breath very much of it. It is beneficial high in the atmosphere, but a pollutant down here, at least in high concentrations. No doubt a Google search will uncover some interesting stuff, along with a lot of commercial sites selling hyped up and expensive generators.

[This message has been edited by Randy (edited 02-10-2002).]

02-10-2002, 03:15 PM
I use a bit of bleach in my coolant to keep the rancidity out. Does wonders.

C. Tate
02-10-2002, 08:09 PM
any suggestions on the amount of copper to use per gallon of coolant?

02-10-2002, 08:49 PM
I don't have any suggestions on amount of copper...I have a CNC that holds about 20 gallons of coolant..I just get some copper on the vise and take about 20 passes or so about .010 deep, just enough to get fine shavings....I was told this method by a coolant salesman...But I have noticed more life out of my coolant...Because I have one particular job which are hydraulic pump housings made of ductile iron...I do the copper thing any time i am going to machine these parts...i don't have it down to a science yet..but it does work...better to have to much copper than not enough i suppose....


02-11-2002, 12:48 AM
ha ha...

Ozone would most likely be bad for the coolant as it reacts with lots of stuff. The bubbler does help (KBC sells them - buy an aquarium pump and save $$$).

Barium salts are used in diesel fuel additive to kill flora in the fuel. I do not know which exact chemical, but a call to a biology or chemistry department at the local University would get some answers. I would also ask if it is save for use, legal, what side effects on other metals, blah, blah, blah...


02-11-2002, 10:59 AM

I scrounged up a scroungy piece of copper tubing last night, stuck it in lathe chuck and made some shavings. Not really that many, but they are now in coolant tank.

I'll report back if I remember.

02-12-2002, 01:23 AM
If any one is interested a good article regarding coolant just appeared in Haas's "CNC Machining" volume 6, #20, 2002. It was written by Carl Kuchler from Valenite. He is a technical consultant for their Valcool coolants & cutting fluids.

www.HaasCNC.com (http://www.HaasCNC.com) (American made, too!)


02-23-2002, 05:34 AM
My 2cents (where is that c-with-the-line-though-it key??)

I have been using Blasocut 2000 on the recommendation of RE Morris, the importers for Harrison lathes. These are my experiences, with a Harrison M300 with about a 7 gal coolant sump, FYI.

I dilute the Blasocut about 8%. No good reason for 8%, it's what they recommend to start with. Incidentally, diluting coolant is the single biggest argument in favor of the metric system I have ever encountered. Try figuring out 8% concentration in fl oz added per gallon. I have changed the coolant completely twice in three years, which I now don't think was necessary.

I have never had any bad smells, ever, despite long periods of neglect or non-use, and some farly major problems. From day 1 I used an aquarium air pump ($5 or so) to aerate the sump. I also installed a skimmer, but I'm not sure I really need it (more later). I feed the air through a 1/4 copper tube about two feet long with small holes (less than #60) along its length that sits in the bottom of the coolant sump. Probably also not necessary, but at least it doesn't float like platic tube. That piece of copper tube had been completely cleaned off by the coolant last time I looked, and was not corroded or pitted or anything, so if the copper is taking part in some reaction, you don't need much of it. Or maybe it's the copper oxide, not the copper...

Ohm BTW, do not use those "air stones" for fish tanks to distribute the air. They clog up fast, and they dissolve in the coolant.

The problem I had to deal with was evaporation of the water. Eventually it gets too shallow for the pump and skimmer. You can't just add add more water, or it will de-emulsify the oil, you have to always add concentrated to less concentrated - just like acid I suppose. I do that with a bucket third-full of water, pump in the coolant until the bucket is full, then tip into the sump. Repeat until refractomer shows the right answer. Don't use the wife's floor-mopping bucket, the air pump will be blowing bubbles for weeks.

The third or fourth time I did this, I was quickly rewarded with a thick, I mean THICK, layer of greenish oil on top of the sump, which the skimmer could remove, but more always came back. No lubricant leaks, which would be black not green anyway, it was the Blasocut de-emulsifying. Well, it was time to clean the sump anyway, so I changed the coolant. The next batch of coolant went about the same way, so I called the Blasocut guys, who were very helpful Can't think why I didn't call them before that...

Of course, the cause of the problem (and so the solution) was "obvious", once you get the right brain cells firing in sync. I had suspected it must be the water, why did it take six months to show up, why did it happen only when I added MORE water? The answer is repeated evaporation, which any fish-tank owner knows the dangers of - as I should. Evaporation removes the water, but not the junk in it, and it is the amount of the junk in the sump that is causing the problem. I mean the dissolved magnesium and calcium salts (that's what the Blaso guy said. Mainly mangesium. Not copper salts, interestingly).

The instructions with the coolant had mentioned high-salt water as being a problem, but as I had no problems initially, I assumed my well water was not too salty. As the water evaporates, the ratio of oil to salt remains the same, so it's still OK. Then, when you add more water to replace evaporated water, you are increasing the ratio of salt to oil. As you repeat this, you add more salt but no more oil, and you eventually reach the point where salt level is too high for the amount of oil, and it de-emulsifies. Depending on your water, this takes a shorter or longer time.

Note that once it starts, the de-emulsification reduces the amount of oil in the coolant and so further reduces the ratio of oil to salt, which makes the de-emulsification even worse. It feeds on itself. If you just added water to get back to your desired concentration, you are in trouble, because the loss of oil will take you down below the corrosion inhibiting concentration. What you end up with is badly-de-emulsified coolant at a low concentration, which equates to free water, probably sitting under your machine slides.

The solution is to use low-salt water, both for initial mixing and replacement of the water. I have used distilled water from the drug store which is expensive, relatively anyway, about $0.30 a gallon?. I have also used the water from the de-humidifier I have in the basement in the summer. Works fine, and appears to be free (reality is about 5 kW-hr of electricity per gallon). Unfortunately, peak dehumidifier output coincides with minimum evaporation (high humidity NE summers), and vice versa (drizabone NE winters). My summer stockpile is getting pretty depleted by now, and it is amazing how fast the water evaporates in the winter.

Anyhow, I have been using low-salt water for about four additions of two to three gallons so far, and the problem has not come back. Also, though this may be wishful thinking, the coolant is working much better with the low salt. In particular, the coolant is no longer discoloring the beautiful ground ways of the lathe, I'm glad to say. The coolant stays emulsified better without high salt levels in the water. Considering the main role of the oil is to keep the water from getting free, this is good. I have noticed the same effect when I use the coolant on the mill with brush application. It used to make a mess under the vise, but now much less.

Also, I think it makes the skimmer work better, since the oil in the coolant is better mixed and "looks" more like water to the skimmer (my theory). Previously, what the skimmer picked up was at least 99% coolant, I just thought it wasn't a good skimmer. Now, what it picks up is pure oil. If I don't run the machine, there is no lube seepage, so the skimmer picks up one drop of oil per hour, if any. Previously, it picked up a pint per hour of something, regardless. Do I need it anymore, I wonder?

Well, that's my coolant story. Part of it anyway. There are other aspects, like the need for splash guards becoming evident when the coolant hits the chuck at 2500 rpm and you get to taste (and wear) oil. I hope it provides some help to somebody. At least I think I understand the whole flood coolant thing better now, and I think I'm where it's more of a help than a hindrance.

Jed Weare

02-23-2002, 12:05 PM
jed, When I type more than 3 lines, my hand starts to hurt...You have some interesting things to say, and I would love to learn from your wisdom...I am not making fun of your age, I just think that you can learn sooooooo much from the "experienced". Welcome aboard this BBS...Now, send check or money order to Brent@jhsll.com....Just kidding....Have you ever had to replace any keys on your keyboard???


02-24-2002, 12:57 AM
I get tired just thinking about typing - I think I need a cute secretary....