last year I used a water based sealer witch our customer spec out for us.We sprayed the sealer on limestone and it caused very light etching.We had only just began when we caught it so it was easy to correct.When  I read the back of the bottle the instructions
mentioned some stones can be etched by using this product.Showed that to the customer and got the ok to use a product that we knew.
Anyway just heard a story that it happened to someone else only with a different water based sealer.  I think siloxanes are corrosive (high alkaline) when not diluted.
But I know that diluted in a sealer they are in small amounts so its not normal for this to occur. Does anyone know why it does occur. Has anyone else had this happen to them?

Stu Rosen
"A posse ad esse "