Neon signs are made of glass tubes filled with gas, bent into letters or other forms. When a high-voltage electrical current passes through the tubes, they emit light. Although these signs were initially made of neon gas, other gases are also possible. The combination of the various tints and phosphor coatings placed on the glass tubes creates a rainbow with more than 50 vivid colors. Neon signs can be as simple as a sign for beer or as complex as a Las Vegas casino facade.

Neon signs were created by a scientific experiment that exposed different gases to high-voltage currents. Heinrich Geissler in 1856 created a light source by passing an alternating high-voltage current through a low-pressure gas enclosed in a glass tube. Many experiments proved that almost all gases can conduct an electric current, and most of them would produce light. The problem was that common gases such as carbon dioxide could react with the current-carrying electrons inside the sealed tube. The electrodes’ efficiency quickly declined until they became ineffective and eventually the light went out. In 1898, Morris William Travers and Sir William Ramsay devised a method for fractionally distilling liquid air. They also discovered the rare gases argon, krypton, and xenon. These gases were used to create colored light sources in sealed glass tubes. These colors were bright reddish-orange for neon and intense grayish blue (or violet) with argon. These gases produced color light, but they were chemically inert and did not react with electrodes.

Fractional distillation was expensive. Karl von Linde, Germany, and Georges Claude, France came up with a more economical method. Georges Claude wanted oxygen to be made for industry and hospitals. Claude started to explore the potential uses of rare gases that are produced by this distillation process. He started to promote neon gas-illuminated signs using the experimental work by Ramsay, Travers, and others. He displayed his first neon sign in Paris at the 1910 Paris Exposition. In 1912, he installed his first commercial neon sign. In 1915, he started to sell franchises and founded the Claude Neon sign company.

Earle C. Anthony, a Los Angeles car dealer, introduced neon signs to the United States in 1923. He purchased two Claude signs for Packard’s business. Neon tubes were used for signage and decorative displays in the 1920s and 30s. They were an integral part of many buildings’ architecture. Las Vegas casinos attracted attention in 1947 with elaborate neon lights.

Neon signs gradually lost their place in the 1950s and 1960s to plastic signs with fluorescent tubes inside. In recent years, neon has been rediscovered as both an artistic medium and a commercial sign. Los Angeles’ Museum of Neon Art features both contemporary and historical neon art. The museum also offers classes. Monthly tours of the most prominent neon displays in Los Angeles are offered.

Raw Materials

Neon gas was originally used in neon signs, but it is now only used to produce reds and oranges. Signs are made of argon, which can be described as an argon/neon combination. To increase the intensity of blue light, a small amount of mercury can be added to the argon. The light can penetrate various light-emitting or phosphorescent materials inside the glass tube to produce different colors. Optic tints are available in many colors if you need strong blue light. You can also leave the glass clear. Xenon or Krypton gases can sometimes create special color effects.

The glass tubing used for neon signs is made from soft lead glass. It can be bent easily and formed. It measures 0.3 inches (8 to 24 mm) in diameter and can be extended to 4-5 feet (1.2-1.25m) in length. Each end is made from very pure iron and enclosed in a cylindrical glass jacket that has one side open. The wire attaches the metal electrode to the envelope and passes through the sealed end. While the tube’s closed end is sealed, the tube’s open end protrudes from the tube.

The transformer converts 120 V of electricity from the electric lines into high-voltage electrical power that powers the sign. It can supply the sign with up to 15,000 V. Transformers are usually twice as big. GTO wire, a special wire that has been insulated to at minimum 7,500 volts, connects the transformers with the electrodes of the sign. This wire can be used to connect sections of an illuminated tube in a series. The wire is connected to the transformer by an insulated housing made of borosilicate glass. It has a spring connection at the end. Sign manufacturers purchase the transformers and wires directly from the manufacturer.

There are several ways to support sign tubing. The framework supports small indoor signs’ sign tubing and power transformer. The sign appears to be floating in space thanks to the black frame. Steel, aluminum, and wood can all be used to support outdoor signs that are large enough for visibility from the outside. The glass tubing is held in place by glass supports with metal bases. It is stored in a cabinet to protect it from the elements.


The art of creating neon signs is as mechanical as it is artistic. Each sign is unique, with a few exceptions. Every sign must fit in the available space. Only the dimensions of the tubing and the length of the transformer will determine the final design. The tubing diameter will be smaller the brighter the light. A tubing with a smaller diameter will require more power, and it will limit the length of the tubing one transformer can handle.

Manufacturing Process

Manufacturing neon signs is mostly a manual task. Attaching the electrodes to the tube and then bending it is the main task. This is the most common process.

Preparing tubing

  • An automated coating machine is used to place one length of glass tubing vertically. The machine sprays liquid-phosphor suspension into the tube and then allows it to drain from the bottom. To dry the coating, the tubes are placed vertically in an oven. This is the same process used to apply color tints. To create an orange-orange or red-orange light, tubes that need to be filled are left empty.

Bending the tubing

  • 2 The sign’s design will be printed on an asbestos heat-resistant sheet. Glass tubing can be heated and softened using a variety of burners. Gas-fired ribbon burners measuring 24 inches (61 cm), are used to create curves in script or round letters. Hand torchers with smaller diameters can be used to heat shorter lengths. Asbestos templates are used to guide you in bending the tubing by your own hand. Tube benders do not wear gloves because they have to feel heat transfer in glass and the degree of softening. This allows them the freedom to choose when to bend. To prevent the tubing’s collapse, the tube bender attaches one side of a piece of flexible hose called “a blowhose”. The tube bender gently blows tubing to reduce its original size while the glass remains soft. Tubes with restricted diameters will not work correctly.
  • For large neon signs, three sections of glass tubing can be used. The practical limits for each section are 8-10 feet (8.2-4.3m). To make each section, the ends of two lengths of tubing are heated and then spliced together. Once the design or lettering for each section has been created, the electrode is heated up and fused to each end. Tubulation is a small port that allows tubing to be evacuated by a vacuum pump. Tubulation ports can be part or separate from an electrode.

Bombardment of the tubing

  • 4 A process known as bombarding is used to remove impurities in glass using phosphors and electrodes. The tubing’s air must first be evacuated. After the vacuum reaches a certain level, dry oxygen can be allowed to enter the tubing until it reaches a mercury pressure range between 0.02-0.04 inches (0.05-1.0mm). If the tubing length is longer, the pressure will be lower. Between the electrodes is connected an extremely high-current transformer. The bombarding process can heat tubing to temperatures of up to 30 microamperes. Glass is heated to 420°F (216°C) by the high current, while the metal electrode heats up to 1400°F (760°C). The heating causes impurities to be forced from the materials, and the vacuum pump eliminates them.

Filling the tube

  • 5. After the tube has cooled, you can insert the gas at low pressure. It must not contain any impurities to ensure the sign is reliable and lasts long. Fill a tube measuring 0.6 inches (15mm in diameter) with mercury to the maximum pressure of 12mm (12mm) mercury. The tubulation port is then heated and sealed.

Aging in the tube

  • 6 After the tubing is filled with gas, it goes through an aged process. This is also known as “burning in tubes”. This is to ensure that the tube’s gas can stabilise and function properly. A transformer is attached to an electrode that draws a voltage slightly higher than the normal operating current. The tube should be fully lit within 15 minutes if neon is used. It may take several hours for argon. An argon tubular can be sealed with a droplet of mercury. To coat the electrodes, the droplet can be rolled from one end to the other after the aging process. The tube should be opened if there is any flickering or hot spots on the gas.

Installation and mounting

  • The framework is wired in-shop and 7 small neon signs are mounted. Larger signs can be mounted in sections and placed on support structures or buildings where they can be wired and interconnected. Large signs can take several months to install.

Quality Control

Proper manufacturing and use of pure materials are essential to ensure a functioning neon sign. A well-constructed neon sign should last over 30,000 hours. An average 100-watt light bulb will last between 750 to 1,000 hours.

Neon signs must meet the requirements of Underwriters Laboratories to be eligible for the UL. To verify this, independent testing agencies must conduct a series of tests. The National Electrical Code must also meet the requirements for neon signs. Outdoor signs must comply with local building codes as well as electrical wiring.

The Future

Small electronic transformers are the latest innovation in neon sign design. They eliminate the audible sound that older neon signs make. Programable electronic controls have replaced the electromechanical cam and switch controls for neon signs that blink, or appear to move.

Neon displays are also being used in consumer products such as telephones and automobile license plates frames. Neon displays can be used to cover large areas of the car’s exterior for a flashy look.

Neon signs will see a revival in interest and applications. Japanese companies have expanded the neon light palette to more than 50 colors. Computer controls allow neon displays to appear more complex and exciting.

Because of its energy efficiency and durability, cost-effectiveness and custom design capabilities, LED neon signs are becoming more popular. LED neon sign is a great option for homes, businesses, restaurants, and bars looking to improve their lighting while also saving money. LED neon sign is great for displaying artwork, signs, or logos. LED neon sign is available in many colors and shapes. This makes it easy to create a unique look for any space. LED neon signs have a longer life span than traditional neon making them a more economical long-term option.

Posted in Blog, Lights, Neon Design Inspirations.

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