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Fixed Glass Removal - Tensioning Devices

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Following up on my Sept., 16th article “Fixed Glass Removal using Braided Filament Friend or Foe”, I thought I might drop back a bit and explain a bit about the trend in using tensioning or winding devices for fixed glass removal.

First, let me explain why the trend is moving in this direction, damage. Over the years damage to the vehicle is costing everyone time and money. Time to tape / repair / touch up scratches and to pay for the primers / tapes. Damage and injuries from metal blades are very costly in our industry in both labor and overhead and medical insurance is not going down. Having a technician out because of injury can cost you thousands in lost man-hours and jobs. Glass design has left moldings behind for the exposed edge glass look and that leaves a serious concern for glass replacement. We no longer have the ability to hide damage with some primer and a molding. Quality and care is more important than speed in this situation.

Traditionally wire has been used for cutting through the adhesive bond for fixed glass. Typically it was used with some form of handles affixed to both ends of the wire and once placed against the adhesive, a sawing action was used to sever the bead.

With the advancement of high tensile strength stainless steel wires, it was possible to just apply a pulling force to the wire and accomplish the same task. Thus began the use of a tensioning device to separate the adhesive.

This started in 1985; in 2008 the first improvement to this technique was introduced. The Glass Bot®

There are three distinct types of winding tools available, manual, power assisted and power.

Manual Winders

Manual winders are the most widely offered.

They are considered the entry-level tools to this method. They consist of a simple spool on a suction cup with a ratchet handle to tension with. They require working from the seated position and using an overhead winding motion to tension the wire. Normal tensioning cycle is a ¼ turn with the ratchet which advances the wire about 1”. As the typical windshield is about 16’ you need a bit over 190 cycles to complete the cut out.

Power Assisted Winders

Power assisted winders are much simpler to build /  a very small spool mounted to a suction cup and a drill motor is attached to spin the shaft and tension the wire. Additional cost to consider is the power drill which range in the $250 to $350 range depending on type / make. These are used in the seated position as well while controlling the drill motor in an overhead location.

Power Winder

For the first time the connection between the worker and the tool was severed and the Glass Bot® was born. The Glass Bot is operated from the exterior of the vehicle allowing full view of the process that is occurring as the Glass Bot tensions the cutting element while being attached to the inside of the glass part. It is based on a large 7” suction cup with an automotive grade DC motor for very high torque and 6’ of cord length for the controller.


The most intuitive thing about cutting with wire is it works best when cutting back in the direction of the adhesive. Now as you cut along the path the angle of the wire will change as will the ease of cutting, it will become more difficult. Most winders will utilize a pulley to redirect the cutting angle and this also creates a sideways force on the pulley. Pulleys attached to the winder will instill a twisting motion upon the suction cup when under force and this can dislodge the winder from the glass. Some winders have two suction cups to prevent this twisting motion.

Now the US market is a strange arena to sell tools into, I’ve been doing this for over 20 years and have a pretty good understanding of the matrix.

First blush is to throw sticks at the new products, second is to check your watch and comment on how much faster you could have accomplished the same task and third is commenting “I’ve been doing this for XX years and I can still do it the same way thank you very much”.

With tensioning devices it gets worse. Common comments are “it take too long to set up”, “it’s defective, the wire broke” and then hit the three normal comments in the paragraph above.

Set Up

Set up time for a winder is simply not a concern or issue in the overall process. It’s mere minutes and just a response from someone who is resistant to change. The wire is threaded to the inside of the vehicle and attached to the winder; the winder is positioned on the glass. The wire on the exterior is routed in the direction of the cut and anchored in some fashion past the starting point. Mere minutes.

Wire Breakage

It hasn’t changed from the old days, when the wire breaks, and it does, it sucks but with winders you can gauge your tension and listen to the sound to prevent the wire from exceeding it’s breaking strength.

Any comment about wire or cutting element breakage is simply what is actively going on at the time on that vehicle, the adhesive system dictates how the process will proceed, it has nothing to do with the tensioning device, just the amount of tension on the cutting element and the adhesive system.

For someone to fault the winding device when a wire breaks is similar to throwing your fishing pole away because the string broke when fighting a fish. It’s not the reel’s fault the string broke; it was the interaction with the fish. So if you fight the adhesive like you would a fish you know when to back off and not push forward because you know the line will break. A tensioning device doesn’t have the ability to tell you to stop tensioning the wire before it breaks. The wire does in the sound it makes and you should pay attention.

Is this the future? Yes and for so many reasons. Should you get started? Yes, because your competitor already has.

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