Water spots / deposits on the back of the car

[jdwk]

This is something I've been dealing since moving to Austin four years ago.

During the spring, it rains a lot and I can't wash the car as much as I'd like. When I do, the dirt on the rear of the car won't come off.
I normally use No-Rinse thanks to the water restrictions, but if the car is dirtier, I'll use the hose and Meguiar's car wash. If I am doing a full detail, I'll use dish soap. None of these have any affect on the spots.

If I attempt to scrub with microfiber, I can get some of it off, but at the expense of swirls.

The only thing I've tried that takes it off completely is a clay bar. I've bought a synthetic clay bar which speeds things up a lot, but it can't clean around the badges well and I still use the old school clay for the tight spots. Then of course, I have to do a full paint correction and re-seal. This is very time consuming and also destructive. It may take a decade or two, but I'll eventually run out of clear coat to polish.

Unfortunately, the picture I took is out of focus, but you can make out the spots. They definitely could be considered water spots, but also could be mineral deposits (I guess a water spot is a deposit). This phenomenon only happens on the trunk and rear bumper of my car. I've been reading as much as I can and scouring YouTube, but I am not sure what product will work best for this problem. There are water spot removers, iron removers, mineral deposit removes, wheel acid, etc. I don't want to buy 5 different $20 bottles to find one that works, especially to find that I still have to resort to the clay and polish.

I typically wax every 6 months with Zaino, NXT 2.0, or Ice Wax. I haven't seen much difference between either of the three in combating this stuff. I am actively researching ceramic coatings since my hope is that it prevents this stuff from adhering to the car, but there are a lot of products and even more opinions to comb through. If I could find something that easily removes it, then I can hold off on the ceramic decision for another season.

 

[Mike PhillipsMike Phillips is verified member.]

The only thing I've tried that takes it off completely is a clay bar. I've bought a synthetic clay bar which speeds things up a lot, but it can't clean around the badges well and I still use the old school clay for the tight spots. Then of course, I have to do a full paint correction and re-seal. This is very time consuming and also destructive. It may take a decade or two, but I'll eventually run out of clear coat to polish.

Unfortunately, the picture I took is out of focus, but you can make out the spots. They definitely could be considered water spots, but also could be mineral deposits (I guess a water spot is a deposit).

I cover water spots in the article below and also in my how-to book The Complete Guide to a Show Car Shine.


3 - Types of Water Spots - Type I, Type II and Type III


Hard water spots, when people say this most don't know what they're even say, it's just a term that's thrown around. It means DISSOLVED MINERALS and other chemicals in the water. When the water evaporates it leaves crusty looking particles behind.

If there is something corrosive in the water it will either leave a crater etching or an imprint ring, they look like this,

This is why I always teach, practice and encourage others to wash wheels and tires first and then wash the car. Otherwise water will be standing on the car for at least an hour as it takes a minimm of about 15 minutes to thoroughly wash one wheel and tires. 4 wheels and tires at 15 minutes each = 1 hours.

In my opinion and experience, Type II water spots are the worst type of defect to remove.

This phenomenon only happens on the trunk and rear bumper of my car. I've been reading as much as I can and scouring YouTube,

In all the scouring and YouTubing, did you find anything that breaks down water spots like this?


3 - Types of Water Spots - Type I, Type II and Type III

but I am not sure what product will work best for this problem. There are water spot removers, iron removers, mineral deposit removes, wheel acid, etc. I don't want to buy 5 different $20 bottles to find one that works, especially to find that I still have to resort to the clay and polish.

If the "spots" are Type II, that is crater etchings or imprint rings you will need to compound. Maybe a polish will work or even a good cleaner/wax but the deal is you will have to abrade the surface to level it.

I typically wax every 6 months with Zaino, NXT 2.0, or Ice Wax.

Interesting. I'm a veteran of the Zaino vs NXT Wax Wars. I wrote the concept paper for NXT to combat Zaino for Meguiars back in 2003. I have 66 page report called,

The Zaino Case Study


Atticus Firey, at the time the Vice President of Meguiar's made everyone in the marketing department and customer care come by my office and check out the paper copy and read it. :laughing: I call this Car Wax History. You wont' ever even hear this type of stuff anywhere else.

I haven't seen much difference between either of the three in combating this stuff. I am actively researching ceramic coatings since my hope is that it prevents this stuff from adhering to the car, but there are a lot of products and even more opinions to comb through. If I could find something that easily removes it, then I can hold off on the ceramic decision for another season.

If it's only happening to the paint on the trunk and rear bumper that's an indicator that they may have different paint.

Me? I always think like this,

WHAT'S IN THE WATER?

Certainly don't want to drink it.


Here's a very cost effective thing you can try that is a lot simpler than a ceramic coating, get some SONAX Polymer Net Shield. Clean and prep the paint by compounding or polishing to remove the offending spots and then apply this stuff. Here's my article on it.

SONAX Polymer Net Shield - Closest thing to a coating without being a coating

My guess is no matter what you do - if the paint is subject to the same water you'll see the same problem.

 

[jdwk]

Thanks for the detailed and thorough response. I had read your article on the types. The stuff on the back of the car isn't really type 1 or type 2. My wife actually suggested that it is pollen that gets dissolved into the water, which is why this only happens this time of year. I guess that makes it type 1, but not the normal mineral deposits.

It looks like the cheapest thing to try for cleaning it off is Meguiar's All-Wheel Cleaner. It did very well in some comparison tests. I guess a more generic wheel acid diluted might be cheaper still, but I can handle the $9/bottle of the Meguiar's and it sticks to vertical surfaces better. I plan on picking some up today.

I think no matter what I use, it will strip the wax or even a ceramic coating if I got that route. All the coatings seem to fail after being hit with these wheel cleaners in these youtube comparison videos. So the cleaner won't really save me that much time over using the clay bar.

The ceramic coating battle I think has finally supplanted the synthetic wax battle, but my Zaino bottle I bought in 2008 is still mostly full, and the NXT I bought around the same time is almost empty. I have PPF on the front and a few other spots, and the NXT is awful to remove from the edges, which is why I picked up the Ice.

I'll report back my results.

I guess I could give that polymer stuff a try as well, but if this is a pollen problem, I may not even see it again for another year.

 

[jdwk]

Meguiar's All-Wheel Cleaner did not work.

The residue or deposits or whatever junk is glued to my car was still there after letting is sit for a couple minutes.

So I broke out the clay bar (Griot's) and soap and water, and it took it right off, but left some nasty scratches and mars. They are light and I'm sure will polish off, but such a big time sink. I don't actually know where the clay bar is picking up the dirt to cause the scratches. I am guessing/hoping it is just the junk that it is removing from the car.

You can clearly see where I used the clay bar and where I stopped in this pic, along with the scratches, but this is all much more visible in person.

I also bought Meguiar's Ceramic Wax. I figure for $15 it is worth seeing if it prevents this stuff from forming again. My NXT was almost out anyway.

After washing my car today with dish soap and a hose, I definitely prefer the No-Rinse method. The hard water just gets everywhere. Every time you think you are done drying, some other crevice spits out some more water.

Well I guess it's off to the garage to get to work, but no way I can finish tonight. I'm leaving early in the morning to potentially add another car to the collection. The current owner used Adam's Paint Coating on it, so if I get the car, I can see how that holds up. Not sure how I'm going to keep multiple cars perfect and still go to work and spend time with my family. Seems like the only surefire way is to PPF the entire car and then ceramic coat the PPF. A friend of mine did exactly that with Expel and Modesta to his GT3 which he paid somewhere around $7k to have done. Seems crazy, but if you add up all the time I've spent on my car, it's probably not more than $50/hr and I am still dealing with it.