How frustrating it can be to run your car through the car wash expecting a clean and streak-free finish, only to find water spots covering the surface. Sometimes it seems, no matter what you do, those annoying and unsightly stains just will not go away. So, what causes water spots on a car? And what is the best way to eliminate them?
What are water spots?
If you notice dusty white spots or rings on the glass or paint of your car after it dries, you are likely looking at water spots. Now, water on its own does not cause spotting. At least pure water does not cause spots on your car. Unfortunately, most water that lands on your vehicle is not pure.
In its purest form, water has a pH of 7, meaning it maintains a balance between being acidic and alkaline. Distilled water usually falls at or very near that number. Water that is acidic has a lower pH, and water that is alkaline has a higher pH. Most water has a pH level somewhere between 6.5 and 8.5. Water spots happen when that balance is out of whack in one of two ways, when it is either too acidic or too alkaline.
When certain chemical compounds enter the atmosphere, usually by way of pollution, they react with water, oxygen, and other chemicals to form sulfuric and nitric acids. Precipitation that has a low pH, or acidic, component is known as acid rain . So, when rain, snow, fog, or hail fall on your vehicle, they leave behind deposits of acid that can etch the paint and other surfaces. Acid rain can leave a permanent mark if it is left for too long. And while the effects of acid rain are more likely to appear on your paint, they can do damage to your windshield as well.
The other way that water spots develop is when the water that lands on your car is full of minerals that are alkaline. Hard water often contains calcium and/or magnesium, each of which has a high pH level, and each of which will cause spotting. The water might come from the atmosphere or by some other means, such as from a garden hose, sprinkler system, or poor quality car washes . As the water dries, the minerals are left behind to dry. And when they do, they create a hard and crusty residue that is not easily removed, especially if they are allowed to bake in the sun for a while.
(Read Why Rain Is Not a Substitute for Washing Your Car )
How to remove water spots
Removing water spots can be tricky. Especially from the paint. In fact, if your paint is showing signs of water spotting, it might be best to leave the repair to a professional automotive detailer. That is because progressive degrees of abrasion are often necessary to remove water spots – especially if they are due to acid rain. And the procedures involved, when done improperly, can cause more harm than good. Unless you are skilled with the use of automotive detailing clay, a power buffer and rubbing compound, and possibly sandpaper, then avoid machining the surface of your paint yourself.
Because glass is much harder than the acrylic finish of your paint, there is less damage that can result when removing hard water spots from your windshield. And because it is far more likely that spotting on glass is due to hard water and mineral deposits than acid rain, all you really need to focus on is one method of repair.
The first step is to wash your car’s windshield thoroughly to remove dust and grime. Washing with pH balanced water and a quality car wash soap can also help to remove some of the minerals responsible for water spotting and to neutralize any acidic residue. Then thoroughly dry the windshield and clean with an automotive glass cleaner.
Next, mix a solution of one part white vinegar with one part distilled water (not tap water that might include more minerals). Apply the vinegar/water mixture to the spots on your windshield with a spray bottle or sponge and allow it to work for ten minutes or so. The acid in the vinegar will help to loosen the alkaline hard water minerals sticking to the glass in the same way that running vinegar through your coffee maker can clean up hard water residue that accumulates there.
After it has done its work for ten minutes, remove the solution with an absorbent cloth. If you still notice the rings, try using a clay bar (with distilled water as a lubricant) to remove what is left.
If the spots are still visible, you might try one of several hard water removers on the market that are made for use on a car. You could also try CLR, but be sure that it does not get on any surface other than the glass, since it is not made for use on automotive components.
If, after all attempts, the spots still refuse to go away, it might be that they are permanently etched into the glass. In that case, while not entirely common, your only option is to replace the windshield.
How to avoid water spotting
You have probably heard the maxim, “An ounce of prevention is worth a pound of cure.” That bit of wisdom applies well to water spots on your car, truck, or SUV. The best way to deal with water spots is to make sure they do not develop in the first place!
So, how do you avoid water spots?
- Park your car in a covered spot. If you can, park in a garage or carport where it will be less likely to see rain or snow. By doing so, you will avoid not only rain and snow from accumulating on your vehicle, but you will keep it clear of sprinklers and other sources of hard water. It is equally important to maintain your vehicle when it is not being used.
- Dry your car as necessary. If your car does get wet, try to dry it off as soon as possible, especially if you know that the rain (or other water source) in your area is a likely cause of water spots. Keep a soft towel or chamois handy and keep your car as dry as possible to avoid spotting.
- Wash your car regularly. When chemical compounds are allowed to remain on the surface of your car, they have more time to bake on hard or eat their way into the finish. A simple solution is to wash your car frequently – at least once a week when water spots are likely. Just make sure that you either perform a careful hand car wash or drive it through a quality automatic car wash where they use recycled water and filter it before use.
- Keep your car coated with paint protection. Another way to avoid the effects of water spotting is to keep your paint and glass coated with protectant. Car wax and sealant serve as a protective barrier against chemical compounds. They each allow water to bead up and run off, carrying destructive minerals away. Rain-X and other glass sealants also help to protect the outside of your windshield.
(Read why you should avoid Washing Your Car In Hot Weather )
If you are concerned about water spots on your windshield or other parts of your car, you might consider a car wash membership that encourages you to keep your vehicle clean and protected. Many businesses offer car wash extras, such as Armor All Extreme Shine Wax and Rain-X Complete Surface Protectant that guard your car between applications of wax and sealant by hand.
Columbia Auto Care & Car Wash | Author: Mike Ales | Copyright
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