Editor’s Note: This blog post was originally published in December 2016 and has been revised to reflect industry updates.
Some people may think that all glass is made the same. Yes, glass can come in different shades and shapes, but its actual composition cannot be altered, right?
Different products call for different types of glass. Two common kinds of glass are low-iron and clear. Their properties differ because their ingredients aren't the same, so one may be better suited than the other for certain design projects. Glass experts can explain the differences between low-iron glass and regular, clear glass and which kind might be the right choice depending on the circumstance.
Regular, Clear Glass
While “clear” is in its name, clear glass is not the clearest type you can get.
Although clear glass does not have substantially high iron content, it is higher than low-iron glass. Due to this higher iron content, clear glass has a greenish tint. This is a result of the natural presence of iron oxide from elements such as sand, or from the cask or container in which the glass was actually melted. Despite being a logical process, this quality can cause issues.
If you’re looking to have the glass back-painted or coated a specific shade of yellow, for instance, your glass fabricator won't want to use regular clear glass because it will be harder to match the color. For this reason, glass fabricators will typically recommend low-iron glass instead. Another application is displaying elegant wares, such as jewelry. These fine details and subtleties may not be as apparent due to even the slightest touch of green present in a clear glass case.
Float glass manufacturers create low-iron glass, also known as extra-clear glass or optically clear glass, by reducing the amount of iron in the molten glass formula. This type is more transparent than regular glass, and doesn't have that greenish tint. In fact, modifying the iron content can increase the light transparency by 5 to 6 percent.
When used in interior walls, low-iron glass also increases the flow of natural light when compared to conventional clear glass, allowing it to be used in a variety of different applications.
With a clearer canvas to start with, back-painting or coating is much smoother, making the finished product the exact shade you wanted. Therefore, architects and designers prefer that glass fabricators use low-iron glass when color matching.
“Due to its composition, low-iron glass can transmit up to 91 percent of light compared to the 83 percent associated with conventional clear glass, allowing it to be used in a variety of different applications.”
Since the edgework of low-iron glass is clearer and less green than clear glass, it's not just great for color matching—it is also great to use for display cases and shelves in retail stores—leading to opportunities for potential conversion through compelling product displays.
According to conversion consulting firm Invesp: “8 out of 10 impulse buys are made in a brick-and-mortar store.” Because of the transparency of glass, consumers can view the merchandise without that pesky green tint in the way. This could also be useful within areas such as hotel lobbies, office waiting areas, or any facility utilizing glass display cases.
So can I use glass that doesn’t contain any iron?
Some level of iron is necessary for the glass to be produced. So, remember: A little iron is a good thing when you want the glass to last.
Determining the Differences
Whether your needs require clear glass or low-iron glass, it’s best to work with a manufacturer that understands your goals and design elements. They can draw upon their experience and successful best practices to ensure the project is completed on time, on budget, and at the highest standards.
Contact us to determine if your project is best suited for clear glass or low-iron glass.