How to make a Neon Sign

Step 3: Putting the gas into the Tube

Neon tubes are capped off by two glass electrodes which have wires passing from outside to inside. One of these electrodes has a tubulation, a small tube which remains as a passage from outside to inside. The tubulation is sealed to the pumping system or manifold. The manifold has glass stopcocks or valves that allow sections to be selectively opened or closed.
An ultra high-vacuum pump pulls the air out of the tube while a high voltage-high amperage transformer bombards and heats the remaining air to produce temperatures in excess of 500 degrees Fahrenheit. This allows the tube to achieve a higher degree of purity. When a very high vacuum is reached and the tube begins to cool, a small amount of inert gas is introduced from a flask or tank. The tubulation is then heated. As it is pulled, it sucks in to make the tube's own seal.

Bending the Glas	Index	The Final Steps

 

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