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How to get rid of water spots on car paint

Getting water spots off a car- sometimes easy, sometimes not so easy

by Kevin Farrell of Kleen Car Auto Appearance

Water spots can be a huge problem in some areas of the country because of the mineral content in the water. You may have noticed those nasty spots just won’t come off after you have rinsed off your vehicle or your car was in the path of the sprinkler system. Water spots are caused mainly by city water and the mineral content found in the city water. Water that lands on a vehicles surface whether its glass or paint, will bead up slightly depending on the surface tension. On cars with very poor paint or extremely oxidized paint, the paint will be more porous and the water will seep “into” the paint more and not cause as much water spotting. But on cars like this, water spots will generally be the least of your problems. On newer cars and vehicles that are kept in much better condition, the problem will be more visible as the water will bead up much more on the surface. Usually water beading is a good thing but when city water is left standing on a paint surface, it’s not such a good thing. The water needs to be wiped off and dried to prevent water spotting. If city water is left on the surface the sun will evaporate the water leaving only the minerals behind. These minerals will adhere, or worse, “etch” into the paint surface and bond with the paint causing an unsightly blemish ring, or water spot. 

The main cause of this is car washing and not drying the car quickly enough, or from a sprinkler system running daily and a car being in the path of the spraying water. You may ask why do you not get this type of spotting when it simply rains? Rain from the sky should not leave spots on a vehicle unless it’s in an area of major industry and the rain water is being mixed with emissions from factories and other atmospheric pollution. This effect is called acid rain spotting which will look kind of similar but have a different make-up. Generally acid rain spotting is more gradual and the spot has a more grayish tint. You won’t see the “hard” outline of the spot quite as much and it also won’t be quite as immediate. In a water spotting situation people will complain that the car looked great last week or yesterday, but today there are all kinds of spots on it that just don’t seem to come off easily or at all.

Many people may also get this spotting on only one side of the car. This would definitely be a case of water spotting as the side of the car facing the sprinklers was the side that constantly got hit. So, once you know its water spotting, what can you do about it?

The chemical make-up

Water spots would be considered an alkaline based mark. That is, the minerals in the water are alkaline based as opposed to acid based when you look at things on a level of PH. This is very important to distinguish as you need to know what to do about the spots if you are to chemically remove them. To remove something that is alkaline based, you want to use the “opposite” type of cleaner on the PH scale which would be a product that is an acid base. If a detailer or a consumer tries to use more water, or simply soap to remove water spots, they won’t get very far because it’s almost neutral as far as PH goes. The cleaner needs to be more acidic to counteract the alkaline based water spotting. But now you have to know what an acid based cleaner is and how to use it effectively and safely to accomplish the removal.  

Many detailers that know that water spots are an alkaline base will use an acid based wheel cleaner to take care of the spots. Luckily a consumer who may be reading this article cannot get their hands on a product like this, but a detailer has to be extremely careful with any kind of acid based cleaner. While hydrofluoric acid, sulfuric acid, or even a safer oxalic acid will probably do the job, they are dangerous to use if you do not know the PH, concentration level and dilution of that product. Without getting into how to make a harsh acid safe to use, I will just say, this method should NOT be used. But what acids can be used without fear of harm to you or the vehicle? 

A safe acid cleaner

A safe acid that you can buy in a supermarket is white vinegar. It’s a weak acid that you can eat or drink and if you mix it about 50% with water it should be a fairly effective water spot remover. You can mix it in a spray bottle and spray it on and wipe it off and see how it works. It may or may not be 100% effective. You didn’t think there was a miracle cure did you? Because white vinegar is a weak acid and has a higher PH level, it won’t work the way an acid based wheel cleaner would, but you don’t have to worry about safety with this product. If the vinegar solution won’t work alone, you can try it with some clay. The combination of the agitation and minor abrasives in the clay combined with the acidity of the vinegar solution will add to the cleaning ability. You can use the clay and vinegar on both paint and glass. On glass you can get a little more aggressive. You can try the solution with a little bit of 00 grade steel wool. This method usually tends to be pretty effective removing the water spots on glass. But there still is a possibility that any of these combinations won’t work well on either glass or paint. If the vinegar solution will not work, and the clay bar along with vinegar wont work, then the problem is a bit more serious and more aggressive methods need to be taken. For those of you thinking “I will just get my wheel acid and start spraying it all over the car”, hold on a second. While I also have done this, I will say it’s not the safest thing to do. Even though I know exactly the PH, concentration and correction dilution of wheel acid I use, it’s still not very safe and surely a consumer or a regular car enthusiast cannot employ this method, so we won’t even discuss it regardless of how it may work to remove the spots. 

The water spots are still there!

There is a chance that after trying these suggested methods, the water spots will still be there. The spots may have “etched” into the clear coat or the vinegar solution may not have been strong enough. Remember, these are the safe, easy for the consumer methods. If the spots have etched in, more aggressive but still safe methods have to be employed. We have a safe, acid based cleaner that is stronger than white vinegar but still extremely safe and effective. It was originally developed as a wipe off cleaner for the workers at the car plants. We also found it to be a safe and mild interior cleaner, an excellent window cleaner, as well as a terrific water spot remover. It’s a unique product that can be diluted a few different ways for various purposes and is very safe for the vehicle and the user. I use it with a micro fiber bug sponge or micro fiber towel to remove tougher water spots. Again the cleaner can be combined with clay to be slightly more aggressive. 

But……if the spots or partial spots still remain… will need to buff the surface. In most cases if the water spots were this difficult to remove, chances are the paint surface was a bit too porous with little or no wax protection, so it won’t hurt to lightly buff it. Now if you are a consumer reading this article you may be a bit afraid to do this, or you may not have the correct products to do this. I always recommend using a machine to buff the paint. It does not have to be a rotary machine in most cases when water spotting is the main problem. There is a great orbital machine used with foam pads that can get the job done. We have this entire package in a great kit where a consumer can do this themselves. Of course all of our buffing kits come with our "Buffing with Confidence" DVD to assist you in doing the job correctly. This also can make a great gift come holiday time for the person who would like to take care of their own car as well.  

We hope this article has been helpful to you and we hope you can find other helpful ideas or products on our website