I read recently on a window washer's website that acid free removal of hard water is the best way to get the minerals off of glass because acid will have long term affects to the glass. This is his selling point. He says that most window washers use an acid-based hard water spot remover that damages glass, but is very quick. They thus choose speed over value.
Is there any good basis for this claim.
He says that half the pros out there do it intentionally, while the other half is ignorant. I'm sure he didn't take a poll...
As someone who has done acid-based hard water spot removal for years and has seen nothing but great affects on glass, I see this as an untruth. Perhaps he has been misinformed. Chemical manufacturers would not be allowed to brand and sell their products like they do if their product damages glass with proper use, glass being the surface it is intended for. At the very least, their product would be called out by many users, lawsuits would occur, and products would be taken off shelves or reformulated.
Of course, these statements of his aren't necessarily malicious. It is likely just ignorance that has allowed it.
Perhaps he had a bad experience in which he misused a product. Perhaps there is a bad product out there that I haven't used. Of course, making a sweeping generalization based on one product, or worse, based on the misuse of a product is like saying that a baseball bat can't hit a thrown baseball effectively after the bat was pushed like a pool stick toward the ball.
Note that he didn't expound upon what the damaging affects were or how he received his information.
His stated method of choice involves spraying pure water on the window, then buffing a rubbing compound. He say's it takes up to ten times as long to do than the acid way, but because he keeps the "interest of the customers" first, he is willing to do this. He also states that his method helps prevent future hard water spotting.
I am not necessarily against other methods, and I know other wc guys buff our spots. I just wanna get some feedback on this guy's claims.