It is the best of times; it is the worst of times. You and your shop team have slowed work for some seasonal downtime or you’re all enjoying a well-deserved vacation for the holidays. That’s the best part.
The worst part is your machines aren’t running. Picture them. There they are, just sitting there—waiting. Of course, no coolant is flowing through the lines because nothing is happening. Or is there?
The fact is, even though your coolant is just sitting there, things are happening with it. How do I know? I’m Ed “Tramp Oil” Thaves, Coolant Private Eye. Here’s a case in point that happened a year ago. The names have been changed to protect the innocent.
It was a dreary January morning, the first day back at work after a long holiday. My phone rang. It was Constance Costanza.
“Mr. Thaves?” she asked. I could hear the worry in her voice.
“May I help you?” I said.
“I’m calling from Denmark Tool and Die. We’ve got a real stinker of a problem here. I really hope you can help us.”
“Don’t hang up, I’m on my way,” I said as I jumped into my coolant-mobile. “Okay, you can hang up now,” I said as I walked through the front door at Denmark.
“Wow! You’re quick!”
“Let’s see if I’ve got this figured,” I began. “Your shop team opened the place up after a little holiday break and they got a bit of an eye opener. Am I right?”
“More like a nose-opener,” Connie shot back with a wince.
“I’ll tell you what, Connie. Let’s get your shop floor team assembled and we’ll try to piece this little mystery together.”
A few minutes later we all were gathered on the shop floor. Connie was cheerfully passing around a tray of leftover Christmas cookies, but no one had much of an appetite given the overpowering smell of rotten eggs.
I sniffed the air carefully and said, “I think I know what may have gone wrong with your coolant.” Pacing among the gathered Denmark employees I said, “If my guess is right, when these machines were last shut down, they had been running for some time on a big project that just had to get out before a deadline.” The shop manager looked at his machine operators. “And let me guess, these machines probably leak a lot of oil into the coolant; but hey, who has time to fix the leaks when production must come first?” Heads were nodding.
“With a little more investigation and a few interviews with your team, it’s my guess we’d discover that the sump level was low and the person responsible for filling it decided to add just plain water instead of a mixture of coolant and water.” Joe, one of the machine operators was staring at his shoes.
“Oh come on guys,” I said, “it’s understandable. You were thinking that you just added coolant two days ago and besides, the coolant barrel is way over on the other side of the plant. Part of the answer to this mystery is right there,” I pointed at a sump. “When that machine was shut down, the coolant concentration was unacceptably low.”
Now I strolled back to Connie, looked her in the eyes and asked, “Mind if I borrow your coffee mug?” Her response was stunned silence. She held the mug up for me to take. I drank the last few drops of her hazelnut-flavored coffee and made my way to the shop-floor faucet. I picked up the hose and ran some water into the mug.
“Who wants to take a sip of this?” I asked, holding the mug in the air. No takers.
“You see, guys, if you had purified, ultra-filtered water coming out of that hose and into your sumps, you’d also help to solve this problem. Don’t feel too bad though, most shops are like yours; the water that was added to the coolant was moderate to very hard. What this means is that, over time, the water evaporates and the minerals in the water stay behind. As the water continues to evaporate, and this happens every day, the hardness of the water in the sump continues to increase. Finally, you get to a point where the hardness or minerals in the water interfere with tool life by becoming an abrasive to the metal and the hardness will also keep the rust preventive in the coolant from doing its’ job. So we have a low concentration of coolant along with high mineral content in the water and, which explains why the brave guy who stuck his head in the machine while holding his breath saw rust on the machine surfaces.”
You see, the coolant did everything it was designed to do when used properly; you just haven’t helped it much. The coolant concentration slipped and they ended up with mixed mineral-laden water with it.
“Here’s the long and the short of it,” I said. “While these machines were shut down, the tramp oil that leaked into the machine over time started to accumulate without anyone noticing, because it simply mixed in with the coolant. There may have been a little oil floating on the surface; but, since the sump is completely sealed and you can’t see the coolant without removing a metal cover-plate, no one knew how much tramp oil was actually in the sump.” Again, heads were nodding.
“When the machine was shut down and the flow of coolant stopped, the coolant didn’t just sit there. The oil started to float to the surface. The longer the coolant sat there, the more oil came out of it. This by itself is a good thing; although, since the oil wasn’t removed, the oil simply sealed the surface of the sump and bacteria started to grow beneath the surface. Some bacteria will breed and grow in the absence of oxygen and in this case, that’s exactly the environment you provided for the bacteria. And this, my friends, was the cause for the terrible odor you smelled when the machine was turned on.
Connie looked pleased and satisfied that the mystery had been solved, but I wasn’t done.
“You need to know you made some damaging decisions here without even realizing it. Remember when you decided not to add coolant to the water when the sump was low? You were actually deciding not to add the lubricant that the tools need. Further, you were deciding not add the rust preventive that was needed to protect the machine surface along with the finished parts. Worse yet, you were also deciding not to add biocide to kill or control bacteria.”
Connie smiled proudly as though her decision to bring in a coolant private eye had been justified.
From that day on, things have improved at Denmark Tool and Die. In fact, this year, Connie sent me a jar of herring with a note that read:
Dear Ed, I can’t tell you how things have improved here since your visit. Today, when we come back from our holiday break, the situation is very different. At 6 AM when the machines were turned on, the operators were happy there is no odor. They can get right back to work making great parts that won’t rust. We don’t even have to think about the problems that were avoided by the coolant being properly maintained. That’s because, before the machines were shut down this year, Joe talked the shop manager into installing an oil skimmer to remove the tramp oil. Joe also educated the other operators about the importance of testing the coolant concentration and maintaining that concentration at the proper level. This helped prevent the machined surfaces from rusting and proved to be just the right amount of biocide to keep the bacteria in check.
Of course, I can’t forget to tell you about our water! Treating the water to remove the minerals and iron contamination has really made a difference to the longevity of the coolant. With good water, our coolant is lasting longer.
Thanks to our private eye coolant guy, our smelly mystery has been solved!
--Your friend, Connie
Isn’t it good to know that some detective stories have happy endings? If you have coolant related problems, I’d be happy to help you with them. You can find the answers to the most common questions online at our S.C. Chemical Solutions Center at www.scchemical.com, or, you can write me via email. Have a great New Year!
This article originally appeared in Shop Talk magazine in January of 2008. Shop Talk is published
by Magellan Publishing.
