The process of making neon signs


A neon sign is made up of glass tubes that are filled with gas and bent into letters, or other decorative shapes. The tubes emit light if a high-voltage electric current passes through them. These signs were originally made out of neon gas. But other gases can be used. Combining these colors with the various tints, phosphor coatings, and glass tubes can create a rainbow of 50 vibrant colors. The neon signs can be as simple or elaborate as you like.

It was a scientific experiment where different gases were exposed at high voltage currents that led to the invention of neon signs. Heinrich Geissler, in 1856, created a light-source by running an alternating current through low pressure gas contained in a glass tube. A series of experiments revealed that almost all gasses could conduct an electrical current and most gases would produce light. Many common gases, such as carbon dioxide, would react with current-carrying electronic in the sealed tube. The efficiency of the electrodes was rapidly reduced, until they stopped functioning and the light died. Morris William Travers & Sir William Ramsay invented a method to fractionally dehydrate liquid air in 1898. They discovered the rare gases argon, Krypton, as well as xenon. They created colored light sources by using these rare gases in sealed glass tubes. The colors ranged between bright reddish to orange for neon to intense grayish–blue (or purple) for argon. These gases not only produce colored light, but are also chemically inert. Electrodes cannot react with them.

Fractional distillation was costly. Karl von Linde of Germany and Georges Claude in France devised a cheaper way to do it. Georges Claude had originally intended to create oxygen for industry and hospitals. Claude began to research potential uses for rare gas produced through this process. He began to promote illuminated signs made out of neon gas through the experimental work of Ramsay, Travers, among others. He made his first commercial installation in 1912. In fact, his first neon sign was displayed at a Paris exposition in 1910. In 1915, he sold franchises and established the Claude Neon sign agency.

Earle C. Anthony from Los Angeles, who was a car dealer, brought neon signs to America in 1923. Anthony bought two Claude signs and introduced them to his Packard business. In the 1920s and 1930s, neon tubes were used for decorative and signage. They were an integral part in many buildings’ architecture. Las Vegas casinos started to draw attention in 1947 when they used elaborate neon lights.

In the 1950s, neon signs were gradually replaced by plastic signs illuminated inside with fluorescent tubes. Neon has made a comeback in recent years as both a marketing sign and an artistic medium. Los Angeles’ Museum of Neon Art showcases both historic and contemporary neon art. The Museum of Neon Art also offers classes. It hosts monthly tours of famous neon displays around the city.

Raw Materials

Neon gas was first used in neon signs. It is now used only for producing reds or oranges. Signs are made out of argon (an argon-neon mix). To increase the intensity, a small amount is added of mercury to the argon. The light can penetrate different light-emitting materials and phosphorescent material to create different colors. Optic tints can also be used to produce strong blue light. Or, you can leave the glass as is. Xenon and Krypton gases are sometimes used to produce special colors.

Glass tubing for neon signs made of soft lead is bendable and easily formed. It can be extended upto 4-5feet (1.2-1.25m), and is approximately 0.3 inches in diameter (8 to 25mm). The electrodes at both ends are made of very pure Iron and protected by a cylindrical glass jacket. One side is open. The wire attaches directly to the metal electrode. It then passes through the sealed envelope. The tube’s tube’s opened end protrudes inside the tube, and the tube’s sealed end is sealed within its end.

A transformer converts 120V electricity from the electrical wires into high-voltage power, which powers the sign. The transformer can supply the sign up to 15,000 V. Transformers are often twice as big. GTO wire connects the sign’s transformers to its electrodes by using special insulation. This wire is also used to connect individual sections in a sequence of illuminated tubes. An insulated housing with borosilicate borosilicate lenses and a spring connection at one side connects the wire to a transformer. Sign makers order the transformer and wires through an independent manufacturer.

There are many ways that you can support the sign tubing. The framework supports indoor signs with small sign tubes and power transformers. The black frame gives the sign an illusion of floating in space. Outdoor signs large enough to be visible outdoors can be supported by steel, aluminum or wood structures. The glass tubing is supported by glass supports that have metal bases. A cabinet is used to protect the transformer from the weather elements.


It is both an artistic and a mechanical task to produce neon signs. Every sign is unique with the exception of a few very rare exceptions. Each sign must be sized to fit the space. The dimensions of your tubing, how bendable it is, and how long you can run the transformer all will determine the final design. The tubing diameter is proportional to how bright it is. A smaller diameter tube will require more power. This will reduce the number of tubes that one transformer can handle.

Manufacturing Process

Producing neon signs is mainly a manual job. The process involves attaching electrodes to the tubing and then twisting it. This is a very common procedure.

Preparing tubing

  • An automated coating machine cleans one length glass tubing and places it vertically in the machine. The machine sprays liquid, phosphor suspension onto the tube. It then allows it drain out of its bottom. The tubes are then placed vertically on a baking sheet to dry the coating. The same process is used for applying color tints. To make a red-orange and orange light, the tubes must be filled with neon.

Bending tubing

  • 2 The sign’s entire design is printed on an asbestos heatresistant sheet. The glass tubing is heated gently and softened with various burners. Gas-fired, 24-inch (61 cm), ribbon burners can be used to make curves in script. Smaller hand torchers can be used for heating shorter lengths. The asbestos template is used to guide you as you bend the tubing. Tube benders wear no gloves, as they must feel heat transfer and glass’s degree of softening. This allows them decide when to bend. The tube bender attaches the one-end of a flexible hose, called a “blowhose”, to stop the tubing falling apart. While the glass is still soft, the tube bender blows the tubing gently to reduce its original diameter. Tubes with narrow diameters won’t work well.
  • Large neon signs are made from three sections each of glass tubing. Limitations are 8.2-4.3 m per section. Each section is formed by heating two sections of tubing at the ends. The electrode is then heated and fused to each of the ends after the design or letters have been created. A small port, called tubulation, allows tubing can be evacuated with a vacuum pump. A tubulation port is either a part of an electrode or a separate section that connects to the tubing.

Bombardment on the tubing

  • 4 The process of bombarding is used for removing impurities and phosphors from glass. First, remove all air from the tubing. Once the vacuum has reached a specific level, dry air can be allowed back into the tubing to reach the mercury pressure range of 0.022-0.04inches (0.5-1.0mm). The tubing will have a lower pressure if it is longer. Between the electrodes, a very high-current transformer can be connected. The bombarding process can heat tubing up 30 milliamperes. Glass can be heated by high current to temperatures of 420degF (216degC) and 1400degF (1400degC). The heating causes the impurities within the material to be forced away and the vacuum pumps removes them.

Filling out the tube

  • 5. Once the tube cools, the gas can now be inserted at low tension. You must ensure that it is free from any impurities so it can work well and lasts for a long period of time. A tube measuring 0.6 inch (15mm) in diameter must be filled to the max pressure of mercury (12mm). The tubulation port will then be heated and sealed.

Aging and the tube

  • 6. The ageing process is used to preserve the finished, gas-filled tubing. This process is sometimes known as “burning of the tubes”. This is done to ensure the tube’s internal gas remains stable and works properly. An electrode is connected directly to a transformer, which often draws slightly more current than the usual operating current. If neon is used, it should be fully illuminated by 15 minutes. It can take several hours to illuminate argon. A droplet or two of mercury can be added before the argon tubular is sealed. To coat electrodes, the droplet of mercury can be added to an argon tubular after it has been aged. If there is any flickering of the gas or a hot spot in a tube, the tubing must be opened and the bombarding/filling procedure repeated.

Installation, mounting

  • 7 small neon signs will be mounted to the framework and wired by an electrician in-shop. You can mount larger signs individually and attach them to the support structure. The installation of large signs can take many months.

Quality Control

To make a neon sign that works properly, you need to use only the best materials and manufacturing techniques. A properly built neon sign should last for more than 30.000 hours. The average 100-watt lightbulb will last between 750 and 1000 hours.

For neon signs to be listed under UL, they must conform with the Underwriters Laboratories requirements. Independent testing agencies must verify this by performing a number of tests. The National Electrical Code sets forth the requirements for neon signs. Signs placed outdoors must be in compliance with local building codes, and electrical wiring.

The Future

Modern neon sign designs include small electronic transformers. These reduce the audible hum of older neon signs. Programmable electronic control is replacing the electromechanical switch and cam controls that were used to control neon signs that blink or appear to move.

Additionally, neon displays can be found in consumer products such telephones and license plates for automobiles. There are neon displays that cover large areas of the exterior to make the car truly flashy.

You can expect neon signs to experience a resurgence of interest and applications. Japanese companies now offer neon lights in more than 50 colours. Computer control allows neon displays to appear more complex or exciting.

Due to its energy efficiency as well as durability, cost-effectiveness, flexibility and customization capabilities, led neon signs are becoming more in demand. Led neon signs can be used by businesses, bars, restaurants, and homeowners who want to increase their lighting efficiency while saving money. neon signs are great for showcasing artworks, signs, logos, and other information. LED neon signs can be made in a variety colors and shapes. It is easy to personalize a look for any space. LED signss last longer than traditional neon making it more affordable and long-lasting.

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