Why Wire?

The Change that Rocked Our World
When automotive engineers started using adhesives instead of rubber gaskets to retain the glass parts in a vehicle, numerous tools were designed and tested for aiding in the removal of these parts. Initially the most basic and prolific tools were the Cold Knife and Piano Wire. The Cold Knife came into existence and to this day still don’t think anyone actually knows who designed it. Another tool that was used initially was piano wire wrapped around two wooden dowels for handles. Well, we have certainly come a long way with the vast choices of tools we have to choose from now, but the more things change, the more they remain the same.

Advances in The Basics

Where the Cold Knife has remained somewhat unchanged other than the array of blades available, the use of piano wire has generated some interesting accessories to make it a much simpler method for removal. Some of the drawbacks initially were that it took two people to perform the function: one person pulling from the outside of the vehicle and another person is pulling back from the inside to facilitate the sawing action that was required. This second person was replaced with some unique inventions that attached to the inside of the glass with a suction cup and with the addition of a spring, was able to replicate the return pull of the person inside the vehicle. Equalizer’s SideWinder™ performs very well and was a great improvement over the previous method and made it much easier and less expensive in man-hours to use piano wire again.

Larger Glass = More Urethane
As the glass sizes on the vehicles grew larger, so did the bead size of the urethane that bonded them to the body of the vehicle. This increased the amount of strength required to cut the adhesive and the piano wire was being stressed to its limits to get the job done.

Wire Evolves

About this same time several improvements to the wire itself were made. One was the invention of stainless steel wire drawn into a square profile that offered four cutting edges instead of a rounded surface that the traditional piano wire had. This greatly improved the cutting action and provided less friction, which produced a cleaner cut. The other improvement was braided wire. The braided wire has similar features and benefits of the square wire in that it presented a surface area that was more abrasive than the smooth round surface of the piano wire. Not only was the surface of these new Windshield Cutting Wire designs an improvement, but also the breaking strength of the wire itself was improved dramatically.

Wire Angles
	One of the most critical factors to successful cutting when using wire is the angle the wire enters and exits the adhesive bead. This remains the same regardless of how the wire is moved through the urethane. Sawing or pulling, a steep angle of over 90° results in an inefficient cutting action, as the wire will require more pressure for it to be pulled through the adhesive.
	A more successful result, with less stress placed upon the wire’s breaking strength, would be to alter the angle to less than 90°.

This chart shows from left to right, how the cutting ability of the wire degrades as the angle increases

Vehicle Design Changes
As more and more vehicle manufacturers strived to deliver vehicles to the market with improved MPG ratings, their main attention was focused on weight and drag reduction. Exterior moldings on glass parts add both of these less than desired results and we see this adaptation in the newest models coming to market with open and painted pinchweld and raw edged glass parts. The tolerance between the edge of these glass parts and the body panel has also been reduced in order to reduce wind turbulence, which develops drag. This created a dilemma to the AGR market, the need to develop new tools and techniques that would eliminate the possibility of paint damage. Previously moldings would cover any paint damage in the pinchweld area resulting in the removal process, the market is now faced with repainting this area if damaged.

Vehicle manufacturers, just like you, are looking for any savings in operations they can find. Part reductions that also contribute to weight reduction, wind turbulence, and labor cost are at the top of the list.

Windshield moldings are going away. The new design is for exposed edge glass, no moldings and tighten the tolerances of the gap between the glass edge and the body panel. Most have a gap of the thickness of a credit card as on this backglass.

This change in vehicle design has let to the current review of wire winding tools as the preferred method for removal without paint damage.

A New Direction In Wire Tools
As the difficulty in the removal process increased and the strength of the new Windshield Cutting Wires improved, in 1986 an inventor in Europe came up with the idea of using a device, which mounted to the interior of the glass, to pull the wire through the adhesive from the exterior inwards. Using a ratcheting lever attached to a pulley wheel to wind the wire upon, the technician would draw the wire taunt with enough force for it to cut through the adhesive and release the glass from the vehicle. This new direction removed the potential of paint, molding and glass damage experienced when pulling the wire outwards using the previous methods. Many European vehicle manufactures adopted this new tool and technique as a recommended method for removing the glass. This new application and technique using Windshield Cutting Wire has spawned even more tools and new training of technicians in this new “old” method of
glass removal.

Wire Winding Tools
The Roll Out 2000 has been available for over 25 years and is specified by various European car manufactures. Belron® has introduced their new tool, EZI-Cut® and technique using their EZI Wire®, to their technicians and is actively training with these wire removal processes.

Roll Out 2000	Belron® EZI-Cut®

Glass Bot™

The first automated glass removal tool brought to the market, the Glass Bot™, was launched in September 2008. The Glass Bot™ is operated via a Remote Control so that the wire can be observed both inside and outside the vehicle to ensure the wire does not catch against clips, moldings, glass stops or electrical connections during the operation. The operator does not touch the tool during the removal process as the tool is attached to the interior of the glass.

I feel we will see a trend towards wire removals being revisited for the benefits they provide with safe damage-free and strain-free auto glass replacements using new state-of-the-art equipment.

So, if you are assessing your future training of your technicians or reviewing new tool purchases for 2012 and beyond, take a new look at an old technique that has been brought into the 21st Century to see what is offered to ease your burden of future auto glass removals.

Rick Nelson
Nelson Glass Tools
Inventor of the Glass Bot