I have experienced this with only a couple different formulas over the years. One was Sansco Window Cleaning Soap with a 26 degree ammonia added to the bucket. Another was a cocamidopropylbetaine amphoteric surfactant at 35 degree active with ammonia. Both had the tendency to leave a film on the glass in just the right sunlight. Which could be seen easier on the inside. So I tried to use it just outside.
Retrograde is when you can actually move backward with the squeegee as much as a full inch when turning the corner. So it makes it so much easier to make that finishing pass. When there isn’t enough slip the rubber will actually grab the glass and leave a little “half moon”. Some of this definitely is connected with the glass surface. I know when I polish a plate with a cerium to make it hydrophylic it becomes possible to fan off that window using pure water.
Does anyone have any formulas that allow for retrograde? I am thinking a TSP or sodium metasilicate with a cocamidopropylbetaine 35% active would be fantastic. Then I could easily snake off a high window with a zero degree Unger handle set totally loose. I have some high triangular windows where this would come in real handy.
Henry
