CPCCJN3005A Cut and install glass

GLASS AND GLAZING

Section 1: Glass

Float Glass

Float Glass, often referred to as ‘standard ‘ or ‘annealed ‘glass, is made by flowing molten glass, then allowing it to solidify, over a bed of molten tin.

The glass is then heat treated, or annealed, to increase its strength and stability.

Float glass is available in a range of finishes including clear, tinted, reflective, patterned or opaque forms.

Tinted Glass

Aesthetics Reduction in Heat Entry (solar gain) Reduction in Glare Improved privacy

Reflective Glass

Reduces solar gain Mirror-effect on outside

Mirror

Mirror is manufactured by coating float glass with silver and protective backing coats. These coats protect the silver from abrasions and damage.

Separate sheets with butchers paper to protect surfaces

Laminated Glass

http://www.rylock.com/images/anim_laminglass.gif

Laminated glass is essentially two pieces of float glass bonded together with a vinyl film in between. This film, otherwise known as a polymeric interlayer, provides added strength. It also increases thermal and acoustic insulation, and prevents glass penetration by holding all fragments together when breakage occurs.

There are two types of laminated glass:

PVB and Resin laminated glass

PVB laminated glass is two or more sheets of glass which are bonded together with one or more layers (PVB) under heat and pressure to form a single piece

Resin laminated glass is manufactured by pouring liquid resin into the cavity between two sheets of glass which are held together until the resin cures.

Benefits of Laminated Glass

Safety Security Sound Reduction Solar Energy Control UV Control Protection from Weather and Natural

Disasters Durability Low Visual distortion

Décor Patterned glass

This is float glass which has a pattern embossed into the glass during manufacture. This is done by passing the semi molten glass through a set of rollers prior to annealing.

One side remains smooth and one is textured.

‘Obscure’ glass and ‘slumped’ glass are all types of patterned glass

Insulating glass units Also known as ‘double-glazed units’

where two or more panels of glass are bonded to a metal or thermoplastic spacer (TPS).

Air or argon gas is used in the space between the glass panes.

Their primary benefit is insulation (Acoustic and Thermal) and solar control.

Most types of glass can be incorporated into an insulating glass unit.

1. Glass2. Air pocket3. Metal spacer section4. Rubber seal5. Desiccant6. Silicone Sealant

Toughened or Tempered glass, is float or patterned glass which has been heated to a high temperature and then rapidly cooled using air jets.

This creates a glass in which the centre is in tension, while the surface is in compression.

Toughened glass

Strength Safety (shatters into small bits or ‘cuboids’)

Disadvantage Cannot be cut, drilled or polished once toughened.

Benefits of Toughened Glass

This is the optimum in safety glass.

Each piece of glass is toughened to provide superior structural strength when compared to annealed glass.

These pieces are then bonded together using either PVB or Resin as the interlayer medium, to ensure that if the glass breaks, the small pieces are held together by the interlayer.

Toughened Laminated Glass

Energy Efficiency in Glass

As homes are heavy users of energy, the Building Code of Australia (BCA) now stipulates energy efficiency regulations for all residential buildings so that new homes will need less artificial heating and cooling.

The type of Glass used can have a major difference in the amount of energy used in a home.

The window energy rating scheme or WERS provides a way of rating certain windows and glass units on a five star scale.

Heat gain and heat loss in glass are just some of the considerations used in the rating.

To find out more, go to: http://www.wers.net/

Heat-gain in Glass

Heat-loss in Glass

Cutting Glass

Glass is a material that requires a particular method of cutting, and if not followed correctly can result in damage or injury.

Glass can be cut by: Hand - using tools which have specially ground

cutting wheels attached to a handle (other types use a small industrial diamond).

CNC machine - Computer controlled, using similar cutting tools to that used by hand

Water Jet – A mix of water and grit (sand) in a fine, high pressure jet, blasting through the glass.

Before cutting any glass:

Check the sizes of the glass to be cut

Determine if any off-cuts can be used up first

Determine the best method of cutting / breaking

Clean off benches and cover with protection

Select appropriate P.P.E.

Good quality glass cutters have hollow handles that contain lubricant (usually oil) for the wheel which is released when pressure is applied.

Glass cutters

Custom Grip cutter

Pistol Grip cutter

To cut Glass by hand: To cut glass, lay the glass on a clean, firm and flat surface that is

covered for protection (felt, blanket or carpet is satisfactory).

Mark the cut size or shape on the face of the glass with a fine point felt marker or white pencil.

For best results use a well lubricated cutter to cut the glass. A single score must be made on the surface with out any misses or jumps. If the cut misses or jumps the score line can be joined although there is no guarantee the glass will break successfully along break line, it may run off.

Once a cut line has been scored on the surface do not run the cutting wheel over the same line as this can fracture the glass or damage the cutting edge on the tool.

Start the scoring at the edge of the glass and apply a firm even pressure and draw the cutter across the face in a single stroke until it runs off the opposite edge. You should be able to hear the tool scoring the line.

To score the glass, hold the glass cutter between the first and second finger, gripping the lower end firmly with your thumb and fingers.

‘Thomas’ Grip cutter

Pistol Grip cutter

Start scoring right at the edge of the sheet

To make square or straight cuts hold a ‘T’ square or straight edge along the set out to help guide the cutter, making allowances for the setback in the tool, i.e. the distance from the cutter to the edge of the tool.

Apply a firm downward pressure on the guide and place the cutter against the edge. Start the scoring at the furthest edge of the glass and draw the cutter back toward you with a smooth even pressure.

Smaller sections of the glass can be snapped by hand.

With your thumbs over the top and fingers underneath, snap the glass with an upward pressure. Larger sheets can be snapped in the same manner, by starting at the edge of the sheet and lifting the sheet slightly, the cut will run along the score line.

Methods of ‘breaking’ glass

Another way to break glass is to gently tap the glass directly below the score line with a sharp object (the back edge of the glass cutter is ideal) until a fracture starts. Care must be taken to tap the glass directly below the score, this method works best if there are no gaps in the score line.

Running Pliers can also be used. They work by placing the pliers over the edge of the glass with its marker in line with the score and applying pressure on the handles. This creates a fracture and will open up or “run” along the line.

Larger sheets can be broken by snapping the sheet on the cutting table.- Place the scored glass near to and parallel with the table's edge but not overhanging. The overhanging section of the sheet must be supported.- Place both hands evenly on the edge of the sheet and apply an even downward pressure, the glass will snap along the line. - When cutting thicker glass

more pressure will be required.

- Lift the sheet slightly andsuddenly, but smoothly snap the sheet down on the table, this will cause the sheet to snap.

Apply an even, downward pressure, and the glass will snap along the line.

You can also break glass by placing a straight edge directly in line with the score line beneath the glass and applying a gentle firm downward pressure on either side. The glass will snap along the line.

Narrow slivers can be removed with special glass pliers with relieved jaws, bylevering down and pulling away from the score line. Smaller sections and thejagged edges can be trimmed back to the score line with glass pliers or bynibbling away the waste with the notches on the back of the glass cutter.

Caution:

Always be careful around glass, especially when ‘breaking’ the cut, or injuries will occur!

Always wear eye protection as glass chips sometimes break off, and cause major damage to your sight!

Speed Cutters

Speed cutters provide a fast and effective way of cutting glass parallel to one edge.

The base plate houses a number of grooved rollers at an angle, allowing them to sit on the edge of the glass and move freely along the edge.

The arm is fixed to the base plate at 90° and consists of an adjustable cutter block and a fixed tape measure.

The cutter can be adjusted to the desired measurement along the arm.

Ensure that the wheels of the speed cutter are properly located on the edge of the glass as shown

When using a speed cutter maintain one hand on the base plate to retain its position on the edge of the glass.

The other hand holds the cutter arm and applies a slight pressure as the speed cutter is moved along the face of the glass creating a score line.

Off-site specially designed machines may be used to cut particular shapes or designs from glass of varying thickness and types.

CNC machines guide laser, plasma or water jet cutting heads that can cut and shape glass to the finest detail and intricate shapes.

Glass cutting machinery

Water-jet cutting

Periodically clean off the glass

Glass edgers

Important points to remember when handling and cutting glass

Always wear safety glasses Wear gauntlets and gloves Never leave glass hanging over a bench Before moving around with glass, make

others aware of your intentions Keep oil cutters oiled! – ….duhh…. Don’t go back over scored lines Always cut glass on a clean bench Check glass for scratches before cutting