Hollow glass tubes that are used to make neon lamps for neon signs come in 4, 5 and 8 ft lengths. To shape the tubes, the glass is heated by lit gas and forced air. Several compositions of glass are used depending on the country and supplier. What is called 'Soft' glass has compositions including lead glass, soda-lime glass, and barium glass. "Hard" glass in the borosilicate family is also used. We at Hope Neon Ltd. use lead glass for most of our neon signs. Depending on the glass composition, the working range of glass is from 1600' F to over 2200'F. The temperature of the air-gas flame depending on the fuel and ratio, is approximately 3000'F using propane gas.
The tubes are scored (partial cut) with a file and then snapped apart. Then we create the angle and curve combinations. When the tubing is finished, the tube must be processed. The procedure is called "bombarding". The tube is partial evacuated of air. Next, it is short circuited with high voltage current until the tube reaches a temperature of 550 F. Then the tube is evacuated again until it reaches a vacuum of 1 micron. Argon or neon is back filled to a specific pressure depending on the diameter of the tube and sealed off. In the case of an argon-filled tube, additional steps are taken for the injection of mercury. Funny, but a large percentage of tubes are filled with argon, but they are still known as “neon” tubes. Not often do people call them an “argon” tube
Red is the color neon gas produces, neon gas glows with its characteristic red light even at atmospheric pressure. There are now more than 150 colors possible; almost every color other than red is produced using argon, mercury and phosphor. Neon tubes actually refer to all positive-column discharge lamps. The colors in order of discovery were blue (Mercury), white (Co2), gold (Helium), red (Neon), and then different colors from phosphor-coated tubes. The mercury spectrum is rich in ultraviolet light which in turn excites a phosphor coating on the inside of the tube to glow. Phosphors are available in most any pastel colors.
Manufacturing process
Lead glass tubing in external diameters ranging from about 8 to 15 mm is most commonly used in producing neon tubes for neon signs. The tube is heated in sections using several types of burners that are selected according to the amount of glass to be heated for each bend. These burners include ribbon, cannon, or cross fires, as well as a variety of torches that run on a simple combination of natural gas (butane or propane work better, however natural gas is cheapest) and air.
A section of the glass is heated until it is malleable; then it is bent into shape and aligned to a pattern containing the graphics or lettering that the final product will ultimately conform to your custom neon sign.
An electrode is melted (or welded) to each end of the tube as it is finished. The electrodes are also lead glass and contain a small metal shell with two wires protruding through the glass to which the sign wiring will later be attached. All welds and seals must be perfectly leak-proof before proceeding further. These electrodes are painted with a special black glass paint that virtually goes unseen and hidden in your custom neon sign.
The tube is attached to a manifold which is itself attached to a high-quality vacuum pump. The tube is then evacuated of air until it reaches near-vacuum. During evacuation, a high current is forced through the tube via the wires protruding from each electrode (in a process known as "bombarding"). The current depends on the specific electrodes used and the diameter of the tube, but is typically in the 500mA to 1000mA range, at an applied voltage usually between 15,000 to 25,000V. The bombarding transformer acts as an adjustable constant current source, and the voltage produced depends on the length and pressure of the tube. Typically our operator will maintain pressure in the tubes as the bombarder bombard electrons hence heating the tube. This very high power dissipation in the tube heats the glass to a temperature of several hundred degrees Celsius, and any dirt and impurities within are drawn off in the gasified form by the vacuum pump. The current also heats the electrode metal to over 600 degrees Celsius, which activates a special coating that scavenges unwanted contaminants in the tube and reduces the work function of the electrode for cathodic emission. When completed properly, this process results in a very clean interior at a high vacuum which is important to producing your long lasting, high quality neon sign.
While still attached to the manifold, the tube is allowed to cool while pumping down to the lowest pressure the system can achieve. It is then filled to a pressure of a few torr with one of the noble gases, or a mixture of them, and sometimes a small amount of mercury. The required pressure depends on the gas used and the diameter of the tube, with optimal values ranging from 6 torr (for a long 20 mm tube filled with argon/mercury) to 27 torr (for a short 8 mm diameter tube filled with pure neon). Neon or argon are the most common gases used; krypton, xenon, and helium are used by artists for special purposes but are not used alone in normal signs. A premixed combination of argon and neon is often used in lieu of pure argon when a tube is to be installed in a cold weather climate. Neon glows bright red or reddish orange when lit. When argon or argon/neon is used, which is used for certain tubes in your custom neon sign, a tiny droplet of mercury is added. Argon by itself is very dim pale lavender when lit, but the droplet of mercury fills the tube with mercury vapor when sealed, which then emits ultraviolet light upon electrification. This ultraviolet emission allows finished argon/mercury tubes to glow with a variety of bright colors when the tube has been coated on the interior with ultraviolet-sensitive phosphors after being bent into shape.
The finished glass pieces are illuminated by either a transformer or a switching power supply running at voltages ranging between 3,000 and 15,000 volts and currents between 20 and 60 mA. These custom neon sign power supplies operate as constant-current sources (a high voltage supply with a very high internal impedance), since the tube has a negative characteristic electrical impedance. The most common current rating is 30mA for general use, with 60mA used for high-brightness applications like channel letters or architectural lighting. 120mA sources are occasionally seen in illuminating applications. Custom neon signs are a type of cold cathode lighting. Your custom neon sign will have a 30ma transformer.
Making Your Custom Neon Sign
Once you have given us either a picture, faxed sketch, or just an idea over the phone, we design a layout, then get it to you for your approval of you custom neon sign. Once you have approved the layout, we glass bend your neon tubes by hand, and build a black acrylic box to suit your neon sign, then we mount the neon to the box. Your neon sign can be hung. Your neon sign has a 120volt plug with an on/off pull chain.
The tubes are scored (partial cut) with a file and then snapped apart. Then we create the angle and curve combinations. When the tubing is finished, the tube must be processed. The procedure is called "bombarding". The tube is partial evacuated of air. Next, it is short circuited with high voltage current until the tube reaches a temperature of 550 F. Then the tube is evacuated again until it reaches a vacuum of 1 micron. Argon or neon is back filled to a specific pressure depending on the diameter of the tube and sealed off. In the case of an argon-filled tube, additional steps are taken for the injection of mercury. Funny, but a large percentage of tubes are filled with argon, but they are still known as “neon” tubes. Not often do people call them an “argon” tube
Red is the color neon gas produces, neon gas glows with its characteristic red light even at atmospheric pressure. There are now more than 150 colors possible; almost every color other than red is produced using argon, mercury and phosphor. Neon tubes actually refer to all positive-column discharge lamps. The colors in order of discovery were blue (Mercury), white (Co2), gold (Helium), red (Neon), and then different colors from phosphor-coated tubes. The mercury spectrum is rich in ultraviolet light which in turn excites a phosphor coating on the inside of the tube to glow. Phosphors are available in most any pastel colors.
Manufacturing process
Lead glass tubing in external diameters ranging from about 8 to 15 mm is most commonly used in producing neon tubes for neon signs. The tube is heated in sections using several types of burners that are selected according to the amount of glass to be heated for each bend. These burners include ribbon, cannon, or cross fires, as well as a variety of torches that run on a simple combination of natural gas (butane or propane work better, however natural gas is cheapest) and air.
A section of the glass is heated until it is malleable; then it is bent into shape and aligned to a pattern containing the graphics or lettering that the final product will ultimately conform to your custom neon sign.
An electrode is melted (or welded) to each end of the tube as it is finished. The electrodes are also lead glass and contain a small metal shell with two wires protruding through the glass to which the sign wiring will later be attached. All welds and seals must be perfectly leak-proof before proceeding further. These electrodes are painted with a special black glass paint that virtually goes unseen and hidden in your custom neon sign.
The tube is attached to a manifold which is itself attached to a high-quality vacuum pump. The tube is then evacuated of air until it reaches near-vacuum. During evacuation, a high current is forced through the tube via the wires protruding from each electrode (in a process known as "bombarding"). The current depends on the specific electrodes used and the diameter of the tube, but is typically in the 500mA to 1000mA range, at an applied voltage usually between 15,000 to 25,000V. The bombarding transformer acts as an adjustable constant current source, and the voltage produced depends on the length and pressure of the tube. Typically our operator will maintain pressure in the tubes as the bombarder bombard electrons hence heating the tube. This very high power dissipation in the tube heats the glass to a temperature of several hundred degrees Celsius, and any dirt and impurities within are drawn off in the gasified form by the vacuum pump. The current also heats the electrode metal to over 600 degrees Celsius, which activates a special coating that scavenges unwanted contaminants in the tube and reduces the work function of the electrode for cathodic emission. When completed properly, this process results in a very clean interior at a high vacuum which is important to producing your long lasting, high quality neon sign.
While still attached to the manifold, the tube is allowed to cool while pumping down to the lowest pressure the system can achieve. It is then filled to a pressure of a few torr with one of the noble gases, or a mixture of them, and sometimes a small amount of mercury. The required pressure depends on the gas used and the diameter of the tube, with optimal values ranging from 6 torr (for a long 20 mm tube filled with argon/mercury) to 27 torr (for a short 8 mm diameter tube filled with pure neon). Neon or argon are the most common gases used; krypton, xenon, and helium are used by artists for special purposes but are not used alone in normal signs. A premixed combination of argon and neon is often used in lieu of pure argon when a tube is to be installed in a cold weather climate. Neon glows bright red or reddish orange when lit. When argon or argon/neon is used, which is used for certain tubes in your custom neon sign, a tiny droplet of mercury is added. Argon by itself is very dim pale lavender when lit, but the droplet of mercury fills the tube with mercury vapor when sealed, which then emits ultraviolet light upon electrification. This ultraviolet emission allows finished argon/mercury tubes to glow with a variety of bright colors when the tube has been coated on the interior with ultraviolet-sensitive phosphors after being bent into shape.
The finished glass pieces are illuminated by either a transformer or a switching power supply running at voltages ranging between 3,000 and 15,000 volts and currents between 20 and 60 mA. These custom neon sign power supplies operate as constant-current sources (a high voltage supply with a very high internal impedance), since the tube has a negative characteristic electrical impedance. The most common current rating is 30mA for general use, with 60mA used for high-brightness applications like channel letters or architectural lighting. 120mA sources are occasionally seen in illuminating applications. Custom neon signs are a type of cold cathode lighting. Your custom neon sign will have a 30ma transformer.
Making Your Custom Neon Sign
Once you have given us either a picture, faxed sketch, or just an idea over the phone, we design a layout, then get it to you for your approval of you custom neon sign. Once you have approved the layout, we glass bend your neon tubes by hand, and build a black acrylic box to suit your neon sign, then we mount the neon to the box. Your neon sign can be hung. Your neon sign has a 120volt plug with an on/off pull chain.
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