Ever wanted to know how custom neon signs are made? In case you didn’t know, neon signs are made of glass tubes that are bent into letters or shapes and filled with gas. When an electrical charge is applied to the tubes, the atoms inside the gas get excited and glow!
To make a neon sign, long straight glass tubes need to be bent using a glass blowing technique. Following a pattern drawn on a fire-resistant sheet, glass benders mark where they need to bend the tube with a marker. Then they heat each spot on a device called a ribbon burner, which uses a propane flame heated to 1200 degrees F. Within about 30 seconds, the glass softens enough to be pliable. The artisans gently bend the tube, then blow into the uncorked end using a flexible rubber tube to restore the original diameter of the tube. With each bend, they check the shape against the pattern and press a wooden block along the tube to equalize the width.
After the glass tubes have been accurately shaped, they cut off the excess. They then attach glass casings which contain electrodes and fuse an electrode to each end of the tube using a hand torch and a latex blowing tube. They seal the glass around one electrode and leave the other one open. Then, using a crossfire burner, they create a tubulation – a thin tube with a small bubble that will act as a passageway to the open electrode. They then fuse the tubulation to that electrode. Then, they carefully inject a drop of mercury into the open end of the tubulation.
Then. using what’s known as an end torch, they fuse the open end of the tubulation to a long glass tube leading to a pumping system, which vacuums out the air then injects the gas. To trap the gas inside the tube, the assemblers use a crossfire burner to remove the tubulation and seal off the open electrode, first making sure the drop of mercury has descended into it.
Next, they dip the back of the sign into black paint and use a brush to spread the coat evenly. This will make the lettering or design stand out. Next, they’ll light up the sign at high voltage for about 30 minutes. This will dry the paint, and more importantly, transform the liquid mercury into vapor that spreads throughout the sign.
Using transparent clips, they mount the sign onto a black Plexiglas background to make it stand out even more, as shown in the below picture.
Finally, they connect the protruding electrode wires to a transformer. This transformer converts the standard 110 volt current from an electrical outlet into high voltage current. Once that’s done, you have yourself an awesome neon sign!
Source: Neon and More How Neon Signs Are Made.