[HuFlungDung]

I'd be hesitant to add bleach to my coolant for fear that at some point, I'd come back in the morning and find my machine all bright orange with rust. I do bleach the sump or whatever when cleaning up, but bleach could possibly destroy the coolant.

I found what I think is a decent fluid lately: Hocut 795, by Houghton International. I figure I have probably the poorest results even with synthetic coolants, because I often let one or more sumps sit unused for a week or more. This Hocut seems to be keeping very well, and no stinky socks odor to it after I start using an old batch.

Some bacteria can cause dermatitis, which is a skin rash. Inhaling them in mist form is not too appetizing either. I say keep it fresh. If it stinks, throw it out. Use what is classed as biodegradeable coolant so you don't have a guilty conscience.

[JEFFY]

Yes you are right about the bleach and coolant, not a very good idea. I only met that bleach was use to sanitze the pit when cleaning it out. and should be rinsed clean before filling. I know of others that used bleach and never had it under control, in fact the job I had with the large coolant tanks the guy that took care of the tanks before me was an old fart and never did anything to the tanks till you walk in the shop and could not stand the smell of the tanks at that point he would add a gallon of bleach and the complain about the finish. Sometimes this was once a week, I started an areation and circulator on the tank after a good cleaning and was able to go 3-4 months with no problems and no bleach.

[lornetw]

Hi everbody - new member.
When I was a cnc operator (I am now a teacher in adult education, teaching CNC's), one of my bosses knew of a really simple solution to the coolant smelling bad.

It consisted of bubbling shop air through the coolant. We just tapped a transparent air hose into the shop airline and weighted the end of the tube. It just needs a small amount of air - so small in fact, that when we went on vacation, we bought little aquarium air compressors to keep the air bubbling through the coolant so that the coolant wouldn't go bad over the vacations. This way, the air compressors can be shut off during the vacations.

I am no chemist or biologist but I guess that the bacteria causing the problem must need an anaerobic environment to grow.

[DieGuy]

Yeah most ot the nasties are anerobic bacteria produced, I bet that an air bubbler would work. Just keeps it oxygenated.

[BillPSu]

The reason for a skimmer is to remove the layer of oil from the top of the sump and allow air to get to the coolant. Anaerobic microbes is the source of most bad smelly coolants. There are germicides available to add to coolant to kill bugs. However the dermatitis issue is always a recurring problems. Coolant itself can cause dermatitis and there have been operators which have developed dermatitis after years of working with the same coolant for unknown reasons. Bubbling air through the coolant will help the problem of anaerobic bugs but it still comes down to good housekeeping in the shop, controlling fines and trash in the sumps, not spitting in the coolant tanks, maintaining concentration levels, keeping tramp oils out of the coolant and cleaning the machines regularly.

[TwinStar]

well me.. I am working in a cnc turning and I clean up the coolant tank and coolant fluid in the (1) one year... the secret is to my opinion to let the coolant fall down and refill it until the end(not every day). Keep it clean.. check the perchentage of oil%
and fill with coolant and fresh water. Is the tempreuture that make it stinky? I Always clean up and refill at the end of summer...

[little bubba]

Two weeks ago me and one of my cronies had the opportunity to check out a quick presentation by one of the Blaser reps. First we have been using Blaser for a year and a half with no stink problems, except for once and that was a low concentration problem. Anyway, I think I learned a lot and am now quite excited about our coolant, not as excited as this guy got, but close, (we talked to him(his name is Uli by the way, really cool guy) for about 3 hours after the seminar about coolant).

I'll try and explain some of the things I learned, stink related and otherwise.

First is what coolant does, it cools and lubricates, I never knew how it lubricated but apparently it has a lot to do with chlorine, chlorinated parafins if I remember correctly, they actually react with the metal your cutting and at the hot part of the chip creat a lubricant of aluminum chloride or titanium cloride or whatever your cutting. This is almost the same as a TiN or TiAlNn coating, just more fragile and thinner, apparently sulfer does the same thing in a straight cutting oil, just it doesn't do it until you reach a higher temperature.

Now the stink factor, most coolant use a biocide to kill all bacteria, this works for a bit until the bacteria become used to the biocide (rapid evolution) and actually feed on it, hence major stinkage. Blaser (my favorite coolant, no affiliation, just a satisfied customer) uses no biocide and lets nature take its course, kind of like a fish tank. Now the things that can make stinky coolant are way lube, impurities (spitting in the coolant, coffee, tobacco, etc) sulfur based cutting oils (tapping fluid). Also mud on the bottom of the tank, this is basically minute particles of metal that creat a 'dead zone' for anaroebic bacteria to live in(stinky).

Other cool things I learned, synthetics are basically the same as solubles without the mineral oil, the only problem with that is the chlorides and other additives can now become airborne with evaporation without the emulsified oils to hold them in, hence shorter coolant life because the stuff you paid for is now floating away in the air instead of in your sump.

I also learned that coolant maintainance is fairly important. Apparantly we abused our cooant, not skimming, never cleaning the sump, mixing incorrectly etc. Mixing improperly can cause an inverse imulsion, similar to a mayonaise, in which the oil holds the water, instead of the water holding the oil, apparently this can make a difference in heat distribution properties which can translate to bad tool life.

On the skimming thing. Coolant is made to promote metal to metal contact so that the chlorides can do their thing and everything happens as it susposed to, however if you don't skim, your waylube gets into your coolant and this type of oil does not promote metal to metal contact (thats why we use way lube, right?) This screws everything all up, now if you don't skim often enough some of your waylube ends up emulsified into your coolant and then things are perpetually screwed up. Also some waylubes have things in them that those stinky bacteria like to eat, hence, stink, also it creates a barrier to the air in your sump, hence anaroebic bacteria, hence stink. I guess most coolant companies make a waylube that is specifically designed to seperate from their coolant for easy skimming, we just bought a bucket of Blaser waylube and it was only $2 more than the chevron purple stuff we normally use.

Another thing learned is about concentrations, if your under concentrated you run the risk of stink. We've always used a refractometer and I always thought that I was just tired when I couldn't get a nice crisp line. Turns out the fuzzy line is mixed in oils that don't belong there. so if the top of the 'fuzzy' is at 12 and the bottom at 10 I would average it out to be 11. WRONG. You need to take the range of fuzzy, 2 on the above example, then invert it downwards, which gives an actual reading of 8, so fuzzy from 10-12 means your actually at 8% and you have a whole lot of oils mixed in.

As for coolant maintainance, skim at least weekly, this also includes the milkshakey stuff between the tramp oils and the 'pretty' coolant, this is the coolant that the tramp oils have been severly beaten into (the fuzzy reading). Also about every 4-8 weeks decant your machine, this involves sucking all the coolant out on a Friday afternoon, sticking it in a drum, and letting it sit. On Monday morning suck the crap off of the top with a wet dry vac and then drain off the rest back into the machine, except the very bottom. This is where all the suspended particles will settle. You may make big chips , but you are also making little chips, and the worst place for these tiny tiny chips to be is being blown into your cut at high pressure, it can be abrasive, therefore lower tool life.

I've gained a whole new perspective on coolant, and I'm very happy with the brand we are using, and the support they will give you(they won't sell through a janitorial warehouse). Its not off the wall expensive, and you never have to throw it away, just maintain it, or not as I've proven through 16 months of total abuse on a 120 gallon sump.

[Fish]

Hi,

I had the same problem using various semi's, synthetics etc from Valenite, Cimcool, Esso. We now use a coolant called "Hocut 795" from Houghton International ( http://www.hocut795.com/ ) that is guaranteed not to smell. So far it has worked quite well, not a bit of smell after almost a year on various machines including some that are only sporadically used. It hasn't damaged paint at all, and isn't hard on the skin. The only thing we noticed is that after using the machine, it is good practice to blow off the inside to stop it from getting a little gummy in the crevices and on small moving parts. And by the way, I don't have any tie to Houghton, so this isn't an advertorial.

Fish

[sendkeys]

Anyone ever tried the chemical add-in they use in ponds/fish tanks? I used it in ponds before and it worked.

somthing like http://shop.petsmart.com/product/253...4441782206.htm

just a idea