Water Spots Question

[rodeo-clown]

A few days ago it rained a fair bit, and I wasn`t able to clean my car for a few days at least...so it was pretty dirty to say the least. I finally got to washing it yesterday, and it now looks a lot better.



I noticed that when I was washing it, while I would hose it down with water and run over a panel with a sponge, I would see water marks. As I would dry the car, these marks would disappear.



Is this just a case of minor water marking and not being able to clean it in time? The car did have 3x layers of SG too.

[White95Max]

Rain contains a lot of tiny particles, that will be left on your paint after the raindrops dry. That`s probably where your spots came from.

You can read my meteorological explanation from a prior thread if you want...

Rainwater spots explanation

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[togwt]

Alkaline watermarks (water spots) are calcium and magnesium salts that deposit on the surface after the water has evaporated, the minute crystals bond to the surface and are not re-dissolvable in water. These fall into one of two categories a) surface or b) below surface (etched) water spots.



As for the â€Ëœpurityâ€â„¢ of rainwater- Air Borne Polluants:

Hydrazine is an extremely active acid that is found in jet fuel. Vehicles that park in close proximity to airports or flight-paths are subject to this contaminant. Hydrochloric acid suspended in a rain droplet, the suns heat greatly accelerates the water evaporation, thereby concentrating the acid, the water evaporates on the paint film surface, and it becomes a Dioxide (a dry concentrate of the acid) a neutral substance, that is until water is added. These conditions should be diagnosed through the use of a 30X magnifier.



Industrial Fallout (IFO)?from power generation, manufacturing plants and combustion engines emit Sulphuric acid from their exhaust stacks etc, vehicular catalytic converters emit carbon compounds that mixed with ozone (an oxidizer) and water becomes Sulphuric acid. Nitric Oxide is an additional IFO component especially around Paper Mills. When ozone, water and heat are applied it becomes acid rain (the pH of rainwater; pure-7.0, Normal 5.5, acid rain 4.3)



"Always add the acid to the water, never add the water to acid" Chemistry 101