Producing
a Neon Tube
The
Making
Most
neon tubes are made from lead or soda-lime glass tubing that
is commercially manufactured and supplied in 4'-5' lengths. Commercial
tubes come either in clear or colored glass and may be coated
with special phosphor powders which contribute to the final color
of the tube when it is lit. In some cases, the tubing is made
from hand blown glass with the help of glassblowers at local
hot glass studios.
The artist
cuts the tubes to desired lengths then "welds" them
together in whatever color combinations chosen using cross-fires to heat the glass. "Welding"
is accomplished by heating the ends of the tubes in open natural
gas fires until they are hot enough to be melted together. Prior
to this welding, the artist may remove some of the powders in
striped or other patterns to enhance the final appearance of
the tube. After sections of tubing are welded together, electrodes
are welded to both ends, sealing the tube and providing the means
by which electricity ultimately can be delivered to the tube
to light it. (QuickTime movie of "welding"-
a large file for fast internet connections only)
This
tube, now the chosen length and color(s) with electrodes attached,
is then bent by Ehlenberger in open gas fires to
the desired 3D shape or pattern. Various types of fires and torches
are used in bending the neon tube, from hand torches that allow
for intricate bends to "ribbon burners" that allow the
artist to heat long sections of tubing at one time
for long, sweeping bends. The welding and bending of the neon
tube is where the skill of the artist comes to play, as the hot
glass is rather unforgiving of error. Mistakes often require
starting all over again! (QuickTime movie of bending in the ribbon fire-
a large file for fast internet connections only)
The
Processing
Once
the neon tube has been bent and shaped to its desired form, it
needs to be processed to enable it to be lit. Processing a neon
tube is is technically demanding as the process must by done
absolutely correctly or the tube will fail to function properly.
The new neon tube is first attached to a manifold, a system of tubes, stopcocks and
gas flasks in conjunction with a powerful vacuum pump. When the
neon tube is perfectly sealed airtight to the manifold, a partial
vacuum is introduced into the tube and a very high voltage current
is applied to the tube, a process called "bombarding". This electrical current
serves to heat the remaining air in the tube to just below the
temperature at which the glass will begin to sag. Heating the
tube in this way vaporizes whatever impurities, especially water,
that have remained in the new neon tube. When the tube temperature reaches its maximum, approximately
200 degress centigrade, a full vacuum is applied to the tube
to evacuate all remaining air and impurities from within the
tube.
Only
when the tube has been thoroughly evacuated can the neon or other
inert gas be introduced into the tube via the manipulation of
stopcocks and gas flasks. Once the gas is put into the tube at
the appropriate pressure (still less than atmospheric pressure,
a partial vacuum), the tube can be removed carefully from the
manifold. The tube is now finished and ready to be used though
it should be aged for a little while to allow the tube to mature.
This
processing of the tube not only requires careful attention to
detail to provide a quality tube but also to ensure the safety
of the individual processing the tube. Voltages in excess of
10,000 volts are applied to the neon tube during processing and
a careless error in this stage can be fatal to the operator.
It should be pointed out that such dangerous voltages are used
only in the processing of a neon tube and not in the neon sculpture!
From
its inception at design to its final manifestation as a luminous
sculpture, each neon tube is hand made and processed individually
with careful attention to detail. Our studio takes pride in the
quality of work generated with the expectation that it will provide
years of trouble free service.
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