hey guys there was no problem with the canopy coming off. I had to pull it off to make repairs to the plane the silicone caulking i use was for doors and windoes just put a small bead of it along the inside of the canopy where it attaches and the smoothed it with my finger and pushed the canopy onto the plane wiped away the excess that squished out and let it cure. no that it has cured it is awesome i lifted the plane by it and it looks great so, if you need to fasten a canopy and you have some extra silicone caulking around just try it.

Thanks for all the suggestions

Chris