Remove any excess oil and contaminants from the windscreen bonding area by wipping it with industrial grade acetone or ideally Pratley Safety Cleaner prior to bonding. Make sure that any previous adhesive is removed.
Next, use either Pratley 1-2-3 or Pratley Ezeebond to adhere the mirror in place. These adhesives are designed to allow for the expansion of the glass in hot or cold environments. Never use an epoxy adhesive for this application as you will risk cracking the windscreen over time. Epoxies will not allow for the expansion properties of the windscreen. Both Pratley 1-2-3 and Pratley Ezeebond have different mixing procedures, so please read the instructions prior to bonding.