Double Glazing Line

Double Glazing Line

Double Glazing Line

At the end of 2021 FGS Glass installed their first Double Glazing Line. This was part of an expansion plan to expand the business from just heavyweight processed glass to all things Windows. As well as ordering a a new Double Glazed Unit Line (DGU), Stock Selection System, Cutting Tables and an Arriser, we also moved from a 5000m2 site in Mount Waverley to a new 12000m2 site in Bangholme, SE Melbourne.

The Forel DGU Line was manufactured in Italy. The Line consists of a Spacer Bender, Desiccant Machine, Primary Seal Applicator and the DGU Line. We also purchased a state of the art Arrising Machine from Forel at the same time. The new factory has the room for the existing heavyweight toughened business, the new DGU Line and also the space for further expansion.

DGU’s are often also called IGU’s (Insulated Glass Units)

What is involved in making a Double Glazed Unit?

A DGU (Double Glazed Unit) consists of the following:-

  • 2 Pieces of Glass
  • Spacer Bar filled with desiccant
  • Sealed with either Polysulphide or Silicon

In some applications you can have Triple Glazed or even Quad Glazed Units but Double Glazed is by far the more common.

What does each part of the line do?

From the video above, you can see there are several steps to go through when making a DGU. The steps are

  • Glass Manufacture
    • Manufacture Glass to suit the particular application and performance you are looking for
  • Spacer Bar Manufacture
    • The spacer bar creates a gap between the 2 pieces of glass to help with insulation. the spacer bar is typically made of aluminium but can be made of other materials that do not conduct heat/cold as much as aluminium. However, these different materials will offer be more expensive
  • Spacer Bar Desiccant
    • Once the spacer is bent the hollow centre is filled with small desiccant beads. This desiccant is used to take away any moisture that may be present inside the sealed DGU
  • Primary Seal
    • The primary seal is heated butyl that is applied to the outside of the spacer bar and is used to attach the spacer bar to both pieces of glass. This seal will stop moisture entering the unit and will stop gasses such as Argon or Krypton leaving the space in the DGU
  • Secondary Seal
    • The secondary seal is the area between the spacer bar and the edges of the glass. In most cases this is filled with polysulphide but on exposed edges, especially with UV exposure, silicon is typically used. This secondary seal gives added protection to the primary seal and gives a nice aesthetic look to the unit


Spacer Bender

Desiccant Filler

Primary Seal

DGU Line

Types of Glass?

Double Glazed Units can have different types of glass depending on the particular performance criteria you may be looking for. Some of the different performance criteria DGUs can offer are

  • Insulation
  • Solar Control
  • Noise Reduction
  • Shading
  • Security

Some of the different types of glass you can use to achieve this performance are:-

  • LOW E Glass (Low emissivity)
  • Clear Glass
  • Patterned Glass
  • Laminated Glass
  • Tinted Glass
  • Acoustic Laminated Glass

Different make ups using these differing types of glass offer different performance criteria.

Why do you use DGU’s?

Double Glazing offers a number of advantages compared to Single Glazed Glass. Double Glazing is a great insulator due to the Air/Argon gap inbetween the 2 pieces of glass. In Summer your single glazed glass gets hot on the outside and radiates the heat to the inside of your house. During the Winter the opposite can happen, the heat from inside your house is drawn through the glass and radiates to the outside world. With a space inbetween this is greatly reduced. Air does not conduct heat as well as glass but argon is even better and conducts less heat that air. So a DGU with argon is the best choice to stop this heat transfer, if you then add a spacer bar that doesn’t conduct heat, you have the perfect solution.

Also with a DGU you can add a Low E (emissivity) glass to the unit, this will then reflect away a lot of the solar heat coming from the sun. This solar heat bounces off of the glass and goes back into the atmosphere. But you can have many different Low E coatings on the glass which can change the performance. More often than not, the higher the performance the more expensive the glass.

By just adding the airgap into the unit you can start to reduce noise transmission. A larger gap gives an improved performance but then you can add a special laminated glass, with a noise reducing interlayer, to further reduce noise transmission.

Finally just by adding the 2 panes of glass to the DGU, you make the opening more secure and more difficult to break and enter. With the additional of a laminated glass with an interlayer to one of the pieces, further improves the security of the unit.

Double Glazed Units are a great addition to any home or office. They have many benefits and can be made to improve your particular circumstances.

Mailing List

FGS Glass


117 Bangholme Road


Victoria, 3175

Tel: 03 8562 0880



FGS Hardware


Welcome to FGS Glass

FGS Glass are 140 years in the making, with a rich history starting in the wool industry. Initially being formed under the George Fethers banner, FGS are now a stand alone Company.

We pride ourselves on Customer Service, Delivering On Time, High Quality and doing what we say we will. Making FGS your 'First Choice in Glass'. We believe we are the best glass processor in Australia.

FGS Glass - Bangholme