Neon signs are made from straight lengths of glass, these come pre-powdered with a phosphor coating. The glass is heated by hand in a flame until it becomes soft, a bit like spaghetti. Once the glass is soft, it is removed from the flame and bent to shape over a paper pattern by hand, air is also blown into the tube at the same time to keep the tubes shape and diameter, this is either done by a mouth piece or by blowing directly into the end of the tube depending on the style of bending. After each bend is completed out of the flame, the glass is returned to the flame to be annealed, this is done to reduce any stress in the glass. The bend then need to cool before the next band can be done, each and every bend is made this way.After the Bending process has been completed, parts are assembled into a section. A section can be a few letters when small or part of a large letter, shape or object. Once part are joined, electrodes are then attached to each end of the tube, the tube is then ready to be pumped.
After the Electrodes have been attached the section moves to the final stages, this starts with the section being bombarded. The section is attached to a machine via some small stemming glass, once a seal is created the section is then put under vacuum, voltage is then applied to the tube once a certain pressure is reached, this applied voltage lights up the tube and starts warming the tube and electrodes up. As the tube warms harmless impurities are given off and then removed with the vacuum, (if they were not removed the tube would either not light or would fail quickly). The pressure of the tube is kept low until the electrodes have been activated and the tube has reached the correct processing temperature. Once the tube has been cleaned and the electrodes activated the vacuum is then increased, the tube is allowed to cool before the required gas (Neon or Argon) is added. Once complete the tube is removed from the bombarder and the placed into the aging bay.
The aging bay part of the process allows for the tube to fully come to life and checks for any problems with the tube. Once the tube is ready, all of the drop-backs (parts that are not needed to be seen) are painted out to give the lettering or design definition.
Article by neon and vintage signs expert - A1deSIGNS