[BORBRYCE]

Spotting and where they come from is obvious once all your equipment and technique are sound. Airbourne dust particles, even in a mild breeze there are millions of them, invisible to the naked eye. They float around and leech onto your wet glass, water evaporates and dust particles remain in the form of spots.
Science has not proved this of course, too irrelevant I suppose. So I have decided this is my down to Earth thesis. And it does make sense.

[Jeff Brimble]

Clean spotting glass with a wfp then squeegee it dry, then pour pure water over it- hey presto no spots, dust or otherwise ??

[BORBRYCE]

Dunno Jeff, why pour pure water over bladed glass? I often see spot like marks on my trad stuff as well when I next clean them, so it's not just confined to wfp. I recon airbourne dust.

[Jeff Brimble]

Yes its the next time round that they are often visible, especially when the sky is blue and the suns at a low angle, maybe  I think the spots are left behind to dry and then maybe the airborne dust that Ronnie mentions sticks to the semi sticky depoits left behind but over a peroid of time they get more spotty ?? 

[mikecam]

If you're getting random pattern spotting then you have just not rinsed enough *. If the spots are in a fine line then its almost certain that its running out of a seal.
 * There are window frames that you will never be able to rinse enough. Poorly maintained wooden frames will always leech dirt, the trick is to stay off the frame wherever possible.
 Twin openers, another bad one. With some its possible to give then a good scrub and you get no run off coming down the centre of the frame. WIth others no amount of scrubbing the centre seems to remove all the dirt. If you can identify one of these problem ones its best to keep the water away from the middle of the openers.
 Some people say turn the water flow up and rinse. I find that on problem windows the force generated by the extra flow exacerbates the problem and a lower (therefore less forcefull) flow targetting only the glass produces results.

[Londoner]

run down off brickwork above is a big one with some houses. Oxidised frames is another

[GB Window Cleaning]

Yes its the next time round that they are often visible, especially when the sky is blue and the suns at a low angle, maybe  I think the spots are left behind to dry and then maybe the airborne dust that Ronnie mentions sticks to the semi sticky depoits left behind but over a peroid of time they get more spotty ?? 

another old topic i know but i feel like im getting some where reading these!

whats scary is that jeff one of the window cleaning masters after 12 years on the pole is still shaking is head about it all!

what he says in this post describes my problem perfect. axcept he did not mention that the spots are still there immediatly after you clean then again in other sords its perminant spotting

[Jeff Brimble]

If the water is at 000tds and the glass is still spotting (and it does despite what others may say )then its a glass problem, I just wish the manuf./installers would stop messing about with it and adding coatings and polishes etc.
On problem windys you could just trad over the glass afterwards without any detailing, which is a shame when you have paid thousands for your kit, wonder why the suppliers always say no problem with our system ?

[GB Window Cleaning]

If the water is at 000tds and the glass is still spotting (and it does despite what others may say )then its a glass problem, I just wish the manuf./installers would stop messing about with it and adding coatings and polishes etc.
On problem windys you could just trad over the glass afterwards without any detailing, which is a shame when you have paid thousands for your kit, wonder why the suppliers always say no problem with our system ?

thanks jeff.

like you said if your rinsing well with decent flow rate and 000ppm it HAS to be the glass!!!

im sure if the custys see these spots in the same light and angle im looking at them in now they would sack me off for a trad cleaner and who can blame them!