If you have ever looked at a glass knob and an acrylic knob and noticed they are hard to tell apart and wondered "which one is better?" Well you are not alone. Many people when picking out knobs for their homes or crafts wonder what are the pros and cons of each and which one should I pick? Ultimately it comes down to your own preferences and needs, but here is a little summary of the differences between the two to help you decide.
[caption id="attachment_137" align="alignleft" width="90"] Acrylic[/caption]
[caption id="attachment_138" align="alignright" width="90"] Glass[/caption]
Both acrylic and glass knobs are made in molds. When you compare clear acrylic and glass knobs, it is hard to tell them apart. There is a slight difference if you look closely; the glass knob reflects light a little differently - you could say it is "brighter." This is due to the fact that glass reflects light a little more than acrylic glass. It is also slightly clearer and easier to see through.
Now acrylic glass is not really glass - it is a plastic, it's true name is poly(methyl) methacrylate or PMMA. Acrylic glass knobs were made as a cheaper alternative to true glass. The advantages of PMMA are that it is shatter-resistant, lighter, and cheaper than glass. However, I would like to point out that even though acrylic is shatter-resistant, it is more prone to scratching at the surface than glass.
The glass used in your typical glass knob is called soda lime glass and it's general composition is 70% silica (SiO2), 15% soda (Na2O), and 9% lime (CaO). The advantages of glass are the greater shine and clarity, it is also easier to clean. Glass is more scratch resistant, but if it does scratch it is harder to buff out than acrylic. Also, as mentioned, glass is more expensive.