This week on the Croft blog, we are going to take a trip through time and look at history and the way glass making has evolved and developed. We have already explored some interesting history, or at least pseudo history, pertaining to the development of the home as a sealed unit where the outdoor temperature and the indoor temperature became viewed as separate things. The idea of an aluminum window or vinyl window being an interface between the two different climates is a notion we traced back through history in order to grasp at a better understanding of aluminum windows, vinyl windows, storm doors, and patio doors - the kind Croft has become an expert in manufacturing. So, in a similar historical vein, our next series of blogs will attempt to more deeply explore the world of glass and its often overlooked components.

We already have a basic knowledge of the process by which glass is made. For a quick recap we can look back at the basic recipe for glass which follows a pretty standard method. The basic recipe is silica, soda ash, and lime. Very high heat melts the mixture which is then poured into whatever mold is needed. By varying different chemicals which can be incorporated into the glass mixture, unique qualities can be created. To manufacture the glass which is placed in vinyl windows and aluminum windows a unique method is utilized. For the absolutely flat surface needed in a pane of glass, the melted mixture of glass making ingredients is poured on top of melted tin. The glass is lighter than the tin, so it floats on top and forms a perfectly smooth face as the glass cools. An annealing process, where the glass (which eventually finds its way into aluminum windows, patio doors, vinyl windows, and just about every other type of home window) is slowly cooled to strengthen it. Then, a tempering process where the glass (still the same glass that makes its way into all those vinyl windows and aluminum windows we know so well) is reheated and cooled very quickly is used to make the glass even stronger. With that basic knowledge, we can start to look at the bigger question of how the glass used in vinyl windows and patio doors has arrived in the form we know today.