Gone-Off Cutting Oil

[Staffordshirechina]

Hi,
I have come to use the coolant in my vertical mill this afternoon and yet again it has gone smelly. This doesn't happen in the lathe or the horizontal mill. Is it possible that the sump in a machine can get infected with some sort of bacteria that mucks up soluble oil and makes it smell and go thin and brownish colour? If so, does anyone have a surefire home remedy?
Cleaning out the sump completely is next to impossible as it is the whole of the internal void of the base casting.

Les

[2tenths]

Dec 19, 2008 17:43:28 GMT Staffordshirechina said:

Hi,
I have come to use the coolant in my vertical mill this afternoon and yet again it has gone smelly. This doesn't happen in the lathe or the horizontal mill. Is it possible that the sump in a machine can get infected with some sort of bacteria that mucks up soluble oil and makes it smell and go thin and brownish colour? If so, does anyone have a surefire home remedy?
Cleaning out the sump completely is next to impossible as it is the whole of the internal void of the base casting.

Les

Eyup

When was the pump last run? Soluble does not like to stand still for long periods of time. Commercial cleaners are available....at a price I have used a cupful of Jizer in with whatever is left in the sump and left the pump circulating around the machine for an hour or so. Pump the rubbish into an old bucket, if there is a drain plug drain the dregs out or if it is like my Bridgy siphon the last bit out (no drain plug)

Once you get some clean soluble back in the machine run the pump for about 10 mins. a week.

HTH

Tony

[jonkett]

Many soluble oils have a bactericide in them as standard, because it is a fact that they breed bacteria and smell terrible, this is a well known problem.

To work around this anti bacteria additives are readily available at a price, also careful management of the dilution ratios help keep it in check.

A piece of kit known as a refractometer is sold to do this very job however they come at a price, about £80. If you go to our website www.cromwell.co.uk and put OXD3361010K into the search box and download the user info, all you need to know is there.

[davediy]

Hi Seems I'm having the same trouble here on my mill but the problem is compounded by the fact I have an manual oiler which tends to over oil some of the guides before oil gets to the furthest reaches and the surplus finds its way into the coolant mix.
Needless to say I end up with a thick smelling skin on the surface over time.
Ive been using a paper filter on the return feed to the tank which seems to help a lot and keeping the tank out of the light cuts down on the bacteria growth.
Unfortunately when running the coolant in use oxygen is added and the brief amount of light is enough for the bacteria to grow
One of my friends is using the ultra-Violet sterilizer from his old fish pond to remedy the problem on his equipment but whether it works over time is yet to be seen. ;D
2tenths is correct when he says coolant dosn't like to be left still for long periods which i think is the norm for most of our workshops especially in winter.
working in unheated shed
dave

[DaveW]

I don't know if it would apply to soluble oil but when I was potting, to counteract bacteria growth in glazes (75-80% water), I used to add a few drops of Jeyes Fluid to each 5 gallon bucket. This proved to be 100% effective.


Dave.

[ianengr]

Hello Les,

I have found from discussions with others that machines which have coolant stored in the cast iron machine base suffer from this and have found this to be the case myself in a brand new turret mill some years ago, even after washing out etc. from memory it lasted only a week or so. Never had this problem in the steel base/tank of my Harrison lathe in 25 years, tramp oil being the only issue there. There must be a reaction of some kind going on with cast iron, but I've never really bothered to find out exactly what it is.


Kind Regards,

Ian.

[Staffordshirechina]

Hi,
A few facts for the discussion....
The smelly mill in question has a cast iron base. It is in the same room as a large centre lathe with a steel base/tank and that doesn't seem to get the problem. They are both in my indoor workshop which is insulated, double glazed and central heated. This being the case, I guess that such an environment would tend to promote bacteria. Except that the lathe is directly in front of the radiator, whereas the mill is across the room!
My old TOS horizontal mill is next door in the garage which though now insulated and double glazed does not get heated until required, though it is always above 'outdoor' temperature.
That machine is cast iron again but doesn't have the smelly problem.
I did try using some Dettol in the smelly mill but whilst it did make it smell better for a few days, it quite soon went back to normal. Jeyes Fluid is a much stronger alternative and I guess I should try that too
Usage is not clear cut either. My work habits are unusual. I can be at home for 3 months at a time and use the workshop most days. Then I am away all week for several weeks only dipping in for an odd hour or two at a weekend. Neither period seems to be any worse or better and the lathe and horizontal are still OK after many months. In fact the suds tends to evaporate before going off in those machines.

Maybe an exorcism would help??

Regards,
Les

[davediy]

A heated workshop I dream of a heated workshop me thinks you are a bit spoiled.
O I'm soooooooooooo jealous ;D
I know my workshops possessed as I sware every time I put a tool down its never where I left it
Dave

[DaveW]

Les,

Dettol didn't work for me with the glazes either. I made all my own glazes from powdered minerals and these, plus water, seemed particularly prone to bacterial infection. Even after just one week, regardless of ambient temperature, the stench when opening a lidded bucket that had not been treated with a few spots of Jeyes was unbearable. Once bacterial growth had been allowed to start it took a lot more disinfectant to control it.


As I said, I don't know if this will work with suds - it may be quite a a different type of bacteria but if you do decide to try it then I would think you will have to clean out all of the contaminated fluid, flush the system with a dilute Jeyes solution and add some of the neat stuff to your new suds mix.
The only problem I can see with trying it is that some people really hate the smell of Jeyes and can spot it in even a very dilute form ....

I had to retire from potting a few years ago due to ill health but, as I still have a a few tubs of made up glaze tucked under the bench (I always hoped I would be able to resume - must dispose of them really), just out of interest I went down to my workshop this afternoon and opened one up. There was just a feint smell of Jeyes, no stink.


Dave.

[russell]

I don't think the problem lies with cast iron. I have the same problem with a plastic tank. I read somewhere that adding a small amount of domestic bleach cures it but when I tried it I found that it interferes with the rust inhibitor and I had rust patches develop on the mill table.

A similar problem occurs in boat fuel tanks where condensation in the tank produces a layer of water under the diesel fuel. Bacteria grows at the interface and then clogs the fuel filter, usually when you are out in a rough sea and the engine stops! Perhaps running the pump regularly keeps the suds emulsified and prevents the oil/water interface developing?

There is a bacteriacide available for adding to diesel fuel perhaps a little added to the cutting oil before mixing with water will do the trick?

Russell.

[Staffordshirechina]

Dave,
I shall have a go with Jeyes very shortly. I would prefer Jeyes smell to the gone off oil smell!

Russell,
I have come across contaminated diesel quite a bit but it has never had stuff growing in it, just rust. Likewise, I have not come across any diesel additive. Noting your location, maybe it is already in UK diesel? I know they put winterising additives in to prevent waxing.
Recently I went to use some red diesel that had been stored underground in a 45 gallon drum for around 10 years. Being a half full drum, it had got condensation in it but nothing else.
I shall have to enquire at our local marina and see if they know of any additive.

Regards,
Les

[Deleted]

Les, there is a very good one called Soltron. It works, but it was £30 a half litre bottle last time I bought one in 2002!
JB