there is no one all encompassing technique!
As has been said, it depends on things like, flowrate, type and age of frames, paintwork, putty, glass, frequency of clean, type of brush and some other things too if I took the time to think about it!
Oh,v thought of another couple....type of jet in the brush, weather conditions, are you coastal or inland, trees and hedges, closeness to bridges & flyovers, heavy traffic....the list just goes on and on
Have a think about rinsing.....
do you ever watch the water as it travels down the glass? mostly it flows down the path of least resistance, splitting into various runnels and missing as much as it rinses.
OK, on good 'hydrophilic. glass the water will spread perfectly as you rinse, almost drying as it goes, but often - even in the same window frame - you will have some panes that are hydrophilic and some that are hydrophobic.
Something else to consider; all the time you are scrubbing and cleaning the glass you are also rinsing at the same time...if you can actually see particles on the glass (prior to rinsing if you view rinsing as a separate action) do you think that means that if you do not rinse you will leave the glass spotty after it dries?
Not necessarily so, it isn't lumps of visible grit that cause spotting, its microscopic dust that you can't see that causes that (or one of the causes at least) and most of the time there is little in the way of that dust left on visible grit....which is only visible when the glass is wet anyway.
And of course, when you do notice those annoying little bits half the time you have to chase them all the way to the bottom of the glass to be sure you get rid of them....easy enough with good fan jets and a decent flowrate...not so if you have needle jets and a flowrate of about a litre & a half.
If you are only happy if you know you have given the glass a decent rinse (understandable) then rinse with the brush on the glass, and by that I mean with the tips of the bristles just barely touching the glass, if nothing else this at least facilitates the chasing down of those darn tricksy bits of grit!
WFP technique is pretty individual, we all develop our own personalised techniques as we gain experience.
As an example: When I come across a UVPE window that has oxidised frames, I know that the first clean will mean a very heavy scrub of the frame and a good rinse to boot, going back to each window after a few others have been cleaned [if needed] in a similar manner, to re-clean the window, but this time to clean just the glass itself.
In this case I'll also [mostly] carefully rinse 'off the glass'....if I've scrubbed the frames enough, hopefully I'll have removed the worst of the oxidisation from the frames, and the second clean & rinse won't further remove oxidised UPVE from the frames to mar the glass once it has dried.
Subsequent cleans - and the shorter the repeat frequency the better - should mean I can get away with a light wash of the frames, with the glass being cleaned up to the edge of the glazing, and....er, in the case of oxidised frames
an off the glass rinse, as rinsing with the brush "on" might loosen and remove further UPVE oxidisation that will end out spotting the glass.
But on a non-oxidised frame I'd wash and rinse "Brush on" in one continuous motion and be very confident of leaving the window spotless once dry.
As a footnote; On oxidised frames, most especially on upstairs windows directly under the soffet's, the very top of the frame won't have oxidised as the overhanging soffet's & barge boards will have prevented them from receiving direct sunshine during the heat of the day...ergo, as they won't have oxidised providing in yor first clean you've done a decent job of cleaning the tops of those frames, you should be able to clean those top edges confident that you're not going to do a poor quality job.
So, the above is one explanation (long winded maybe
) of how one particular type of window might be addressed....try doing that for ever conceivable condition and detail a technique for coping with it would fill a rather large and heavy tome...or it would if I was writing it anyway
Ian
