Neon signs are fluorescent advertising billboards that are comprised of glass tubes , filled with neon, xenon, and other gasses. The glass tubes are shaped and formed into words, logos, and designs. Each tube has electrodes on either end, and if you apply a high level of voltage (5000+ volts) through the tube, the gasses start to glow brightly. Their namesake is the original gas, neon, that was used in the tubes, and produces a red glow. More recently, things like phosphor coated glass, and other gasses like xenon or argon, allow for a much broader selection of colors. Neon signs can be as straightforward as a typical “open sign”, or as complex as the multi-story displays found in Las Vegas. Although the led open sign has gained popularity recently, nothing compares to the nostaligic look of real, glass-tube neon.
Neon’s first dominant period in advertising lasted from the late 1940′s through the early 1960′s. Since that time, neon signs have been relegated to a lesser role, primarly as window signs. However, more recently, neon is making a big comeback as a serious commercial signage product, as well as in the nostaligic art arena.
These days, neon gas is only used to create shades of red. Just about all of the currently produced “neon” signs use argon, xenon, or other gasses blended together. Additionally, mercury is blended with the gas, lending more intensity to the colors. Phosphorescent coatings accomplish a similar goal, while also adding to the palette of available colors. More exotic and rare gases such as helium or krypton are also sometimes used for specific effects or colors.
A special lead-based glass is required to make the neon signs easier to produce. Electrodes, with a specially-prepared conductive coating are put on each end of the glass tubes by the craftsmen that create the signs. Creating a neon sign is not only an art form, but also a highly technical and demanding process. The artisans must pay attention, because each neon sign is different, and may have different requirements both from an artistics as well as technical perspective. For example, the thinner diameter tubing produces a more intense light, and requires more voltage to fire properly.
Even today, the process of creating a neon sign is done by hand with very little automation. It mainly consists of shaping the tubing with special torches and bending jigs, as well as attaching electrodes and the process of injecting the various gasses.
The glass tubing must be pre-prepped before being used by the end neon sign maker. Lengths of the glass tubing are thoroughly cleaned and then inserted into a machine that coats the interior walls with a liquid-based phosphor solution. The tubes are then dried in a very hot oven. If color tints is required, the process is very similar.
Once the tubes are ready, it’s time to bend them into shape. The glass is heated until soft and then manipulated into the various shapes. Once the bending is complete, the tubes go through a process called “bombardment”. This process removed any impurities that may be inside the tubes…which is crucial because impurities can cause the glow to be dim, or in some cases, keep the sign from working at all.
After the glass tubes have been bombarded, the neon or argon gas is injected. An airtight seal is then made at the end of the tube. The final steps include aging and then final assembly. To ensure that the gas inside the tube stabilizes, an aging period where the sign is constantly lit is accomplished before the final assembly. When you see a neon sign at your local strip mall, think back to this article and all of the tedious, manual processes involved in making the sign.