L3 Materials Topic 2

SUBJECT : MATERIALS LEVEL 3 TOPIC: 2 ITEMOHELENG CAMPUS DISTANCE LEARNING 2020-APRIL LECTURER: KHOSI MOHAPELOA Downloaded from hlayiso.com

TOPIC 2 : GLASS LEARNING OUTCOMES: HISTORY OF GLASS TYPES OF GLASS MANUFACTURING GLASS NATIONAL STANDARDS FOR USING GLASS SAFETY GLAZING REQUIREMENTS GREENHOUSE EFFECT OF GLASS PUTTY CUTTING GLASS Downloaded from hlayiso.com

GLASS Glass is a transparent material, particularly in the visible region of electromagnetic spectrum. The transparent and colouration have made the glasses best suitable for decorative and illumination purposes in the early days of their invention. Today glasses find applications in various fields’ viz., electrical transmission, optical instruments, laboratory glassware, domestic appliances, textiles, optical fibers ETC. Downloaded from hlayiso.com

HISTORY OF GLASS Egyptians used glass to make beads for jewellery = 3000 BCE Small glass bottles were made. These bottles often held perfume = 1500 CE Blow pipes were invented for making glass shapes = 1 CE Glass windows were produced ( was not much clear) = 1400 CE Blow pipes Flat glass was produced = 1959 CE Today glass is produced = Present BCE = BEFORE CHRIST ERA CE= CHRIST ERA Downloaded from hlayiso.com

DIFFERENT TYPES OF GLASS Float glass Safety glass Fire retarded glass Environmental or Sound reducing glass Special glass environmental glass Sound proof glass Safety glass (Thick) Downloaded from hlayiso.com

Manufacturing process for MANUFACTURING GLASS float glass Downloaded from hlayiso.com

Manufacturing process of MANUFACTURING GLASS laminated glass Downloaded from hlayiso.com

Manufacturing process of MANUFACTURING GLASS toughened glass Downloaded from hlayiso.com

NATIONAL STANDARDS OF USING GLASS AS A CONSTRUCTION MATERIAL Sans 10400 = The application of national building regulations Sans 204 = Energy efficiency in buildings Sans 10137 = The installation of glazing Sans 1263 Safety glass and security glass Sans 10177 = Fire retardants Downloaded from hlayiso.com

NATIONAL STANDARDS AND SIZES (REQUIREMENTS) Downloaded from hlayiso.com

GREEN HOUSE EFFECT OF GLASS Downloaded from hlayiso.com

THERMAL PERFORMANCE OF GLASS The effect of different glass thickness on the thermal performance of evacuated glazings of various dimensions range from 0.3 m by 0.3 m to 2 m by 2 m. ... For glazing size greater than 2 m by 2 m, heat transfer coefficient decreases with increasing glass pane thickness. Downloaded from hlayiso.com

PUTTY a soft, malleable greyish-yellow paste, made from ground chalk and raw linseed oil, that hardens after a few hours and is used for sealing glass in window frames and filling holes in wood. Downloaded from hlayiso.com

APPLYING PUTTY ON STEEL AND WOODEN FRAMES ( STEPS) Surface must be thoroughly cleaned & prepared. Remove all dust & loose particles. Steel window frames must be coated with a suitable primer prior to glazing. Teak coloured putty is used on wooden window frames. Wooden window frames must be sealed before using Powafix Multi- Purpose Teak Putty. Powafix Raw or Boiled Linseed Oil can be used to seal timber. Prime dried white putty with Universal Undercoat before painting. Alkyd timber varnish can be applied directly to dried teak putty. 2kgs of putty will glaze approximately 4 metres of window frame. 1kg of putty will glaze approximately 2 metres of window frame. 500gs of putty will glaze approximately 1 metres of window frame. Downloaded from hlayiso.com

APPLYING PUTTY ON STEEL AND WOODEN FRAMES Work putty by hand to make smooth; Work putty into the cavities on the window frames. Shape & smooth with a putty knife. With the glass in place, apply putty on the outside of the glass & onto the metal or wooden window frame smoothing with a putty knife. Putty gradually hardens over 7 – 14 days. Prevent the putty from hardening by folding & sealing the pouch Downloaded from hlayiso.com

CUTTING GLASS Downloaded from hlayiso.com

STEPS OF CUTTING GLASS • Thoroughly clean the glass you intent to cut. • Lay the glass on a clean, flat, layered surface. • Measure the glass to the required dimensions • Score the glass with a glass cutter, using a straightedge for guidance • Snap the glass along the scored line • Smooth out any sharp edges. Downloaded from hlayiso.com

HALLOW CORE, DIAMOND EDGE DRILL-BITS FOR GLAZING Downloaded from hlayiso.com

HOME ACTIVITY  1. With a form of a sketch, depict how toughened glass, float glass and laminated glass are manufactured (15)  2. How does the green house effect impact windows (4)  3. List 5 national standards for using glass as a construction material explain each (10)  4. Discuss the steps of applying putty Total: 29 Downloaded from hlayiso.com

NEXT TOPIC: TOPIC 3 METALS Downloaded from hlayiso.com

THANK YOU THANKS YOU Downloaded from hlayiso.com