Thanks for your write up and the fact that it is still holding up after 1.5 years. Given your info I did a lot of research and 3M, the manufacturer of the product that you used, 3M windo-weld 08609, recommends that you first use a primer on the glass prior to the windo-weld application. The recommended primer is 3M One step primer 08681.

Now, this all is beginning to make some sense, because when my rear window popped out i noted that none of the adhesive remained stuck to the canvas top, but that all of the adhesive was stuck to the window. Closer examination showed that the adhesive was actually stuck to what appeared to be a thin grayish black tape about 1/2 inch wide around the entire window edge. when i took a razor to it all that tape was a freakin bear to remove, while the adhesive on top of it came off much easier. After doing more research, I am absolutely convinced that what i originally thought was tape is actually a dabbing of glass primer put on prior to the adhesive at the factory. A quick look at the 3m website primer chemical composition sheet pretty much confirmed this, as once the primer MEK evaporates, it will leave a compound stuck to the glass that will look like thin tape, and promote the adhesive sticking to the glass. Maybe other forum members might confirm this?

Now, the million $$ question: Did you use any primer prior to using the 3M windo-weld?

BTW, the 3M Single Step Primer costs about $30, too include shipping.

Thanks again -- Bob