The order and placement of each prep or primer are essential to proper molecular bonding and a safe installation. For example, accidentally placing pinchweld primer on the glass can cause molecular failure and a weak bond. Always follow proper bonding procedures as detailed in the Dow Automotive Fixed Glass Installation Guide or manufacturer's directions and place the color-coded cap back on the proper bottle to reduce risks.

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BETAPRIME* primers are moisture curing and once opened have an open life of seven to ten days. Always check the manufacturer's expiration date to ensure the product is within shelf life, mark the day you opened the bottle and secure both inner and outer caps immediately after use. If you're using single-application primer units, check the expiration date printed below the dauber, use, then discard. Do not use material if you're not sure it's within the 10-day open life. When in doubt, throw it out. Note: always record lot numbers so you can prove you used fresh product.

Shaking mixes the solids that may have settled to the bottom of the bottle or single-application unit and ensures a thin, uniform band of coverage. Any manufacturer's primer containing solids should be shaken before use.

Always use a wool dauber or the sponge dauber head of the single-application unit to apply primers. Paper towels are designed to absorb, not to evenly spread liquids. They may also leave unwanted fibers on the glass surface.

It is safer to prep and prime the windshield before attaching the reveal molding. This helps prevent an improper bond between the urethane and the primer. The improper bond is caused by the prep pooling in the molding butyl channel and wicking on top of the primer when the windshield is turned upright.

Corrosion (rust) is a very difficult and serious problem in auto glass replacement. Surface corrosion on the pinchweld (with no loss of metal thickness) can be removed with an abrasive wheel or brush. The metal can then be cleaned and prepared with BETAPRIME U-5201 Bare Metal Etch Primer. It is important to follow the manufacturer's recommendations for preparation and application. When the primer is fully cured, the surface should then be primed with BETAPRIME pinchweld primer.

When corrosion destroys or reduces the metal's strength and thickness, take the vehicle to an auto body repair facility to restore the rusted area to OEM condition.

Small scratches and nicks caused by the windshield and urethane adhesive removal process can be touched-up with BETAPRIME 5404 Pinchweld and Encapsulation Primer. It is important to avoid priming the original urethane adhesive in the bonding area.

Bare metal areas over one-half inch square (as with new body panels) should be cleaned with an approved cleaner and primed with BETAPRIME U-5201. When the primer is fully cured, prime the surface with BETAPRIME 5404.

Many new paint finishes use a clear coat finish that resists chemicals and maintains a glossy finish. This can cause a bonding problem if the clear coat is in the bonding area. Be sure to mask the pinchweld with tape prior to any color coat and/or clear coat application by the collision repair shop. Keep the original urethane intact during painting and body repair. Trim the urethane adhesive to the recommended 1 to 2 mm final thickness just before installing the new glass. This ensures the new adhesive bead is applied directly to a freshly trimmed bed of original urethane.

BETASEAL U-400HV is an OEM-approved adhesive. It requires windshield preps and primers or BETAPRIME 5500 for proper adhesion. A pinchweld primer (BETAPRIME 5404) is required for priming the metal that was scratched during windshield removal.

BETASEAL U-418 and U-418HV are primarily aftermarket adhesives. They do not require windshield preps or primers; the glass prep and primer are incorporated into the urethane adhesive. A pinchweld primer (BETAPRIME 5404) is required for priming the metal that was scratched during windshield removal.

Never use any other manufacturer's primers, cleaners or other chemicals in conjunction with a Dow Automotive adhesive system. Dow Automotive tests to ensure chemical compatibility to all Dow Automotive products. Dow Automotive does not test other brands.

Holding the adhesive applicator at a 90° angle to the bonding surface (glass or pinchweld) forces the urethane adhesive into the irregularities of the surface.