If you live in the Midwest, or if you’ve ever talked to people who live in the Midwest, I’m sure you’ve heard, “I like living in the Midwest because I like the changes in the seasons.”
After this past winter – which seems to have lasted forever – all I can say is, are you kidding me?
After a long, long winter, a little year ’round summer doesn’t sound too bad. But, having four seasons is a fact of life for us and, oddly enough, it leads to some unusual coolant challenges. Shortly after seeing your first robin you will probably start to notice changes in how your coolant systems are performing.
When the weather improves, it’s normal to start opening windows and doors to air-out a stuffy shop. Sounds like a great idea - but the increase in temperature as spring melts into summer also causes the coolant in your sumps to evaporate at a faster rate. This evaporation creates a number of concerns, including uncontrolled coolant concentration, inadequate rust protection, dermatitis, mold, and fungus.
Coolant concentration during the winter is controlled somewhat differently than in the summer. With the water portion of your coolant evaporating at a faster rate because of warmer outside temperatures, you can’t use the same coolant/water ratio that you used all winter. If you do, you’ll see a dramatic increase in coolant concentration. Typically, if you use your coolant at 5-6 percent for general machining during the winter, your make-up coolant would be mixed at 2-3 percent.
That same 5-6 percent coolant mixture will require a make-up solution somewhere around 1.0-1.5 percent during the summer. You need to add more water to compensate for evaporation. The good news is that you won’t have to increase your coolant consumption, only your water usage.
Please remember to check your coolant concentration whenever you are making coolant additions.
Rust protection is always a concern regardless of the weather. Warmer days often bring with it increased humidity and a greater threat of inadequate rust protection.
Coolant concentration is key. If your coolant/water ratio gets out of hand, and the coolant in your sump becomes very strong (say 10-12 percent) you might be tempted to just add water during the next two to three weeks and slowly get your coolant back to where it should be (in the 5-6 percent range). However, what could happen is the rust preventive portion of your coolant might be used up before the lubricating portion of the coolant.
You see, every time you machine a piece of metal, the rust preventive in the coolant provides a film on the metal surface to prevent rust. The heavier the coolant concentration in the sump is, the heavier the rust preventive film. As you add just plain water to your over-concentrated sump, you gradually reach the point where all, or most, of the rust preventive has plated out.
The secret? When you have your coolant at a very high concentration and you want to bring it back to where it should be, always add a small amount of fresh coolant concentrate. Instead of adding just plain water, add a 0.5 percent coolant solution. This will help you avoid potential rust problems.
Dermatitis also is a concern in any season. From experience, I can say that nearly all skin irritation problems are due to excessively high coolant concentration.
The first thing you should do when you get to work, after putting on your safety glasses, is check your coolant concentration. If the concentration is where it is supposed to be and you still have a skin concern, then you can look at some of the other possible causes. Did you work in your yard all weekend without gloves? Are your hands dried out from washing the car? Were you digging in the dirt or handling fertilizer or household cleaning agents?
When you come back to work with those dried-out hands and put them in coolant, they will start to burn! Notice, the coolant didn’t cause the skin problem, it just makes it seem that way.
The solution here is obvious, take care of your hands over the weekend and check your coolant concentration when you get to work on Monday. This will go a long way toward minimizing your chances of having dermatitis.
Please understand that there can be a number of other causes for skin irritations. But the ideas presented here are the ones I’ve found to be frequently overlooked.
Mold and fungus, pollen and ragweed... What would summer be without them? Did you ever notice that TV meteorologists rarely talk about the mold index or pollen in the winter? That's because the plants that produce these irritants are dormant in winter.
More than a nice warm breeze comes through those shop doors and windows you opened when the weather changed. The spring and summer air is filled with all sorts of spores that want to grow. What the heck, it’s spring and that’s what spores do!
You might be unconcerned at first because your coolant salesman told you that the "Super Deluxe Extra Special Coolant" you are buying has enough fungicide to prevent mold or fungus from growing in the coolant. And the salesman was 100 percent correct.
Except, mold and fungus doesn’t grow in the coolant; it grows on the sides of the coolant sump, or on the ceiling of the enclosed sump, or on any surface of your machine that is damp and dark where mold can settle in.
What you can expect is that the fungicide in your coolant will kill most mold and fungus that falls into the coolant. So a mass of mold is growing on the side of your sump and eventually some of it falls into the coolant, how can you tell if it’s dead?
Usually, the fresh, healthy 'plant' (mold and fungus are actually plants) is light colored and slimy, but the dead and dying plant is gray to black and more rubbery. These plants will not harm you if you grab hold and simply remove them from your sump. Fear not! There is no danger of becoming part of the "Blob" from the classic horror film.
The best way to prevent mold and fungus from growing in your machines is to have sumps that are not buried under the machines. With some older machines, the sump can’t be moved. Here we suggest that the machine surfaces be rinsed with coolant at the end of the shift. Many of the machines I see have hose attachments where coolant can be used to flush chips, tables, and the inside walls of the machine. Now, under these circumstances, the fungicide that is in the coolant will prevent mold from getting started.
Please keep in mind that coolant concentration is again an important issue, if the coolant mixture isn’t maintained properly, your fungicide level might fall out of the safe zone.
Ask nearly anyone in the Midwest and you’ll likely hear they are really, really looking forward to a pleasant spring and wonderful summer. Controlling your coolant concentration will give you fewer things to worry about and more time to enjoy the changes of the seasons. If you have concerns regarding coolant problems of any type, please contact your coolant supplier - I know he wants to be of help. Have questions about anything you’ve read here? You are welcome to call or write me.
This article originally appeared in Shop Talk magazine in May of 2008. Shop Talk is published by Magellan Publishing.
