If you are installing a bonded van window for the side or rear of your camper van, you'll need to prime the inside of the glass, then use a strong car window adhesive like Powr Bond High-Viscosity Urethane Adhesive. This auto window primer is an effective first-step primer used by professionals before applying urethane adhesive for glue-in (bonded) van windows. Powr 300 Series Urethane Primer:

• chemically reacts with the glass frit and urethane to provide a secure bond.
• can be used for any bonded-style van windows (clamp-in windows do not require adhesive and primer)
• comes in a 3.4 fluid ounce (100) ml container
• has a shelf life of 9 months in unopened container.
• can be used for 5 days after opening the container and re-sealing after each use
• should be used on the inside surface of the glass where you plan to attach a bead of urethane adhesive for window mounting, and the frame of the vehicle where you will attach the adhesive. Clean new glass first with glass cleaner. Shake primer for one minute before use, apply to glass and metal with lint-free wipe or clean dauber/brush, let dry for 10 minutes.

When mounting van windows:

• If you can, cut the openings with a center-blade shear, rather than a jigsaw - this will cut an opening that may be less ragged, produce less debris, and produce less hammering on the sheet metal of the van.
• Make sure you paint the cut edges of the new window opening - if you skip this step, moisture can rust out the edges of the window mounting.
• Prime the inside contact edge (frit) of the glass where it will be adhered to the van with glass primer
• Use a thick bead of quality urethane adhesive to adhere bonded windows to the van (adhesive and primer not needed for clamp-in van windows).

Specifications: CRL Car Window Primer - Powr Bond Primer