Why do water drops leave marks on glass that won't come off easy?

[Jmanm]

I have water drop marks on my glass windows on my car that are from presumably tape water (after a wash) & maybe the rain (as it sits outside).

 

A few weeks after I already polished the previous grime & water marks off my glass to perfect clean look, the water marks are back again. They don't wash off with IPA or wax & grease remover which is mostly naphtha, despite a hard rubbing action. Again only an abrasive action of polishing gets the water marks off.

 

 

Why is this? Anything that can be done to prevent them? I was hoping just a weekly soapy wash would be enough to remove them.

 

 

thanks

[StringJunky]

Try vinegar in the rinsing water to remove the effects of the insoluble calcium. Or try it neat on the glass.

[Jmanm]

Try vinegar in the rinsing water to remove the effects of the insoluble calcium. Or try it neat on the glass.

Not sure what you exactly meant, but I tried vinegar straight on a cloth rubbing & it did not remove these water marks.

[DrP]

Try giving the vinegar time to act - it isn't a magic wipe - it needs time to act on the minerals to break them up... maybe press the wet cloth onto the mark for about 10 or 20 seconds before scrubbing. It might take some pressure with the wiping too. Maybe wet the glass with the vinegar and leave it for a min or 2 then get wiping with the vinegar damped cloth after it has had time to soak into the stains. Lots of rinsing afterwards too.

 

I find tree sap annoying when it sticks to the windscreen... it should come off easily (which it does) but it doesn't straight away and can smear badly when first wetted and wiped... which can be annoying when driving if the washer bottle isn't topped up fully.

[StringJunky]

When you do get the stains off, wipe the windows with warm water that has vinegar in it to stop residues in the future because it will soften the water. Distilled white vinegar is the purest. I use a good splosh of vinegar in half a bucket of hot water with a few drops of washing up liquid to clean my house windows; polishing is minimal after.

 

If you want numbers and in a bottle:

 

 

Green Living, from National Geographic, recommends this simple recipe, plus a few extra tips for the best window cleaning outcome. In a spray bottle, mix 50% distilled vinegar (white) and 50% tap water. For extremely grimy glass, prewash with very soapy water, then go to the vinegar spray.13 Feb 2013 http://www.greatdayimprovements.com/cleaning-windows-with-vinegar.aspx

Edited June 15, 2017 by StringJunky

[Phi for All]

(as it sits outside).

 

Under any trees?