Windshields:

There are three basic ways that windshields are held in place in any car or truck. Each has advantages and disadvantages based on the use and application it was designed for.

The oldest is called "rubber set" where the glass is secured in a molded rubber gasket. This gasket may be self-locking, may have an insertion locking strip, or be molded such that it must be put on the glass and then "lipped" into the vehicle. This system, which is still used in tractor trailer rigs and some heavy equipment, was designed to allow for a relatively simple means of escape in the event of an accident. Older vehicles did not have fuel shut off switches to prevent fuel leakage and fire; though built stronger than today's vehicles there was a real possibility that the doors might become jammed by impact or captured in a rollover, so the most efficient method of emergency exit was through the windshield. These were designed such that one could use both feet and push the windshield out of the vehicle allowing the occupants to exit safely.

As trucks "came off the farm" and cars became more stylish and sleek, a lighter and more streamlined system was needed for windshields. Butyl tape {some still call it dumdum} began to be used with a metal molding to insure that the windshield would remain in place during an accident. It is from the use of Butyl that the term "tape bed" originated, and is still used today though the use of Butyl is now illegal for some very good reasons that I'll cover in the next section. A windshield installed with Butyl could still be removed in an emergency by "kicking it out", but the general advantages were that there was less leakage and it allowed for a smoother, more streamlined installation.

The windshields in today's cars and trucks are designed to be integral components of the body structure, so the glass must be bonded to the vehicle body. The strength and durability of Urethane fits this requirement nicely. With a sheer strength averaging 1,000 psi or greater, and a lap strength of 1,300 psi or greater, Urethane is the adhesive required by law for every windshield in any private passenger vehicle. A windshield, properly installed, is to stay in place in an accident or rollover. This protects the occupants from being thrown from the vehicle, and provides added structural support for the roof to prevent it from collapsing in on the occupants. If the windshield fails to remain in the vehicle, the probability of

• 1
• 2
• 3
• next page >>

---

Add your voice

Know something about Auto glass: How to replace auto glass?
We want to hear your view. Write now!