Internationally, for glass for picture frames, there are perhaps a dozen different types of glazing materials available to glaze (meaning to cover a surface with a see-through cover) picture frames. Most are made of glass with the rest being plastic, polyethylene boards, Perspex or just clear PVC sheeting. With regard to the glass glazing materials the two major types of picture framing glass are clear float glass and clear float glass is the most common because it is the cheapest. However it has two main disadvantages ...