The Question:
How are Glass scratches removed?
Are the molecules of glass rearrange, lifted or moved to fill in a scratch?

We have had many inquiries over the years asking us about this topic of lifting the scratch by rearranging the molecules to fill it in. There are companies that claim to have polishing systems that can move the molecules of the glass which causes them to lift up and fill in the scratch. This concept is completely untrue not to mention absurd. Anyone with a ninth grade science education can smell the “snake oil” from a mile away. We feel it is time to expose this fraud and let the truth be known.

The premises of lifting the scratch from the bottom moving the molecule of glass sounds pretty simple. Glass is a super cooled liquid. If we take a fast running grinder, magic polishing compound and water. A system like that should be able to generate enough frictional heat to make the glass flow like a liquid and fill in the scratch… WRONG!

To validate this assumption, the example of old antique windows is used. On a lot of old building glass 100 years or older, the window glass is thicker on the bottom than it is at the top. This must mean the glass being a fluid has slowly moved downward due to gravity. This principle should be able to be duplicated to fill in the scratch with a special polishing system.

Here is the problem with this logic: Glass melts at 2600-2900 °F (1425-1600 °C) depending on its composition. These types of glass polishing systems will only bring the glass up to a temperature of 130F-150F at best. Water is used in these polishing compounds and water boils at 212F. Paper burned at 451 F. An egg will fry at 158°F. All of these fall quite short of the glass softening 2600F. Furthermore, if a window glass was heated to 2600F, what would happen to the wooden or vinyl framing around the glass?  Obviously, it would not hold up...

Then what about those antique windows?
The observation that old antique windows are often thicker at the bottom than at the top is often offered as supporting evidence for the view that glass flows over a matter of years. It would then be assumed that the glass was once uniform, but has flowed to its new shape, which is a property of liquid. 

In actuality, the likely reason for this is that when panes of glass were commonly made by glassblowers, the technique used was to spin molten glass so as to create a round, mostly flat and even plate known as the Crown glass process. This plate was then cut to fit a window frame. The pieces of glass created with this spinning method were not absolutely flat. The edges of the glass disk became thicker as the glass was spun. When this imperfect glass was installed in a window frame, the common practice was to place the glass with the thicker side down both for the sake of stability and to prevent water from accumulating in the lead cames at the bottom of the window. Occasionally such glass has been found thinner side down or thicker on either side of the window's edge which was caused by carelessness at the time of installation.

By considering the facts of the amount of heat and energy required to make the glass flow as well as the example of antique glass used to validate the glass molecule rearranging theory, one will see why we stated earlier that this meritless concept is completely untrue not to mention absurd.

If you happened to encounter a company that uses this explanation of how scratches are removed from glass to promote their system, one should question the integrity of the company’s sales tactics as well as the actual effectiveness of their products. When it comes to polishing and removing scratches from glass, there are no magic wands. What is required are products that have been tested to work from a company with a long track record of providing cost effective solutions without the games.

At Janvil, We pride ourselves on our knowledge and expertise in the field of Glass and Plastic restoration products.

It is all we do.

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