How Neon is Made and a Guide to Choosing Colors
Neon signs are made by using specialized torches to accurately bend glass tubes. Signs are made by heating up lengths of tubing and bending them into shapes according to a printed design or pattern. Common size range for commercial neon signage is 8–15 mm in diameter, which are sold in 4-5’ lengths.
The tubes come from the manufacturer as either clear or colored glass, and they can also have an additional phosphor coating on the inside of the tube to get brighter and more complex colors. Once the tube bender has completed the design and welded electrodes onto each end of the tube, it gets filled with a noble gas mixture, usually neon or argon. The color of the light emitted from the final product depends on the color of the glass tube, the type of gas used, and the phosphor coating.
Types of colored glass tubes available for neon bending
The image above is a list of colored glass tubes from a local manufacturer. These tubes have colored glass and phosphor coatings on the insides, which makes these the the brightest, most vibrant and saturated neon colors available.
Types of clear glass tubes available for neon bending
The image above shows the clear glass options from the same manufacturer. A neon sign made with these gets all its color from the type of gas reacting with phosphor coating on the inside of the tubes. While these colors may not be as saturated and vibrant as those of colored glass tubes, they are used to achieve a wider range of colors where basic red/green/blue/yellow would not work.
Some neon signs are made with clear tubes with no phosphor coating. These signs get all their color from the type of gas used to fill them. Clear tubing filled with neon gas produces the an reddish/orange color with the electrified gas clearly visible inside the tube. This being the cheapest and simplest tube to make, it also has a “classic neon” look to it.
A clear uncoated tube filled with neon gas
A clear tube without a phosphor coating can also be filled with argon, although this is less common. Clear tubes pumped with just argon give off a soft purple light which some people find beautiful, but it’s not so common in commercial signage because it’s not as bright as neon.
A clear uncoated tube filled with argon gas
Although rarely seen in clear uncoated tubes, argon gas is more commonly used in coated tubes, where the insertion of mercury inside the electrode significantly increases the brightness of the tube.
Inserting mercury into an uncoated colored glass tube
Different combinations of colored glass, phosphor coating and type of gas used in the tube can create nearly endless color combinations. These manufacturing choices are usually best left to tube benders or experienced neon designers who be able to take into account not only the aesthetic priorities of the client but also lead times from manufacturers and local availability of tubing stocks.