I was able to successfully re-glue the glass back onto the top this past week.
First impressions are very good. The glue seems to be very strong and looks like it will hold very well.
Now I will have to see how long this will last, but from other's experience, some have been going on over 2 or 3 years without issue.

Here's a video of the end result..

 

Very nice! I might have to do that on my 128i one day. Did you post do a write-up?

 

I hope you have better luck than....the rest of us!

 

I hope so. A friend of mine did this to his audi and it has lasted over 2 years and still going. He told me the key to getting a good bond was in the prep work. On my xfire, only the bottom came unglued, but in order to prep it properly, I had to remove the whole glass. I cleaned and removed all remnants of the old glue from the glass and made sure the glass surface was cocmpletly cleaned. I also sanded down the glue from the fabric top and cleaned it as much as possible. Then applied the 3M primer onto both the glass and top. Let the primer dry, Then applied the glue to the glass and attached it to the top. I was told if I prep it properly, the seal and bond should last. I am hoping that it does.

 

My top and the local owners top I fixed are still doing just fine.. and that has been about 1 1/2 years ago.. I didn't primer the canvas side either like OP.. just the glass. Link to video in my signature.

 

I just replaced mine after the repair lasted ~ 1.5 years.

 

Mine is starting to come apart again in one place after only 9 months !