Re: Treatment for acrylics on glass , permanent bond?
For glass you are going to have to sandblast it or abrade the surface some how. I like sandblasted surfaces for painting because it is an even texture. Most glass painting is done with oils but some people do use acrylic. The fact of the matter is that the acrylic will not stick permanently no matter what if there is not some kind of texture. It's the same with plexi, which is why people use glass and plexi for palettes. A finer grit, say 220 or 400 still allows for a great deal of transparency, the finer the grit the more transparent but the less the color will hold.
Sorry, probably not what you wanted to hear but it is what it is.
"I've been wrong on more occasions than I'd like to recognize, but there's room in our vocation if we read between the lines." F.M.