Why Does The Sun Cause Spotting?

Morning lads,

Another day, another thread. Just wondering why the sun causes spotting? I know how to contract it, any windows that are in direct sunlight or may be later in the day I spend longer rinsing. And I get the sun will dry the windows a lot quicker, but surely if the window is already clean (maintenance clean) there shouldn't be any dirt to spot? Or have I been misinformed, does the sun not actually cause it?

It interferes with the rinse. I don't know why, but when bright direct sunlight strikes glass in winter or summer it causes the water to break up into millions of little beads and when it's like this it doesn't rinse well. It may be due to the various coatings that are put on glass these days as it seems to be less of a problem on hydrophilic glass where water sheets well. But on hydrophobic glass it can sometimes be a real pain.

Then again I could be talking complete nonsense ?

The sun doesn't cause spotting that’s caused by not cleaning or rinsing enough or a high TDS , but it shows  up more in the sun at this time of year as it’s a much shallower angle , the spotting would still be there in different light situations but you might not see it so easily 

Pjj said:

The sun doesn't cause spotting that’s caused by not cleaning or rinsing enough or a high TDS , but it shows  up more in the sun at this time of year as it’s a much shallower angle , the spotting would still be there in different light situations but you might not see it so easily 

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Fair enough. I haven't had any call backs because of it but I was just wanting to make sure I understood the reasons properly. 

Master Jedi Alejandro said:

Morning lads,

Another day, another thread. Just wondering why the sun causes spotting? I know how to contract it, any windows that are in direct sunlight or may be later in the day I spend longer rinsing. And I get the sun will dry the windows a lot quicker, but surely if the window is already clean (maintenance clean) there shouldn't be any dirt to spot? Or have I been misinformed, does the sun not actually cause it?

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This is the main reason why summer time cleans take longer than winter cleans. Drier atmosphere and a need to use more water initially, before cleaning, and more rinsing after.

Part Timer said:

This is the main reason why summer time cleans take longer than winter cleans. Drier atmosphere and a need to use more water initially, before cleaning, and more rinsing after.

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Water before cleaning?! ?

Master Jedi Alejandro said:

Water before cleaning?! ?

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We always clean above the glass and make sure the water is already running down the glass before we start

Part Timer said:

We always clean above the glass and make sure the water is already running down the glass before we start

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Ohh so start on the frame? Aye a do that. You had me freaking out, Part Timer ??