| A |
Annealing
The
process of heating a glass object to release the strain introduced
in the forming process.
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Atmosphere
The
relative content of oxygen and fuel in a flame or kiln. Atmosphere
that is rich in fuel particles will affect glass one way (reduction)
while an atmosphere that has a high proportion of oxygen will
affect it differently (oxidation). Usually these affects are greatest
on the metallic oxides used to color glass.
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| B |
Bench
The
working area of the glassblower or lampworker.
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Blow
Hose
A neoprene
tube attached to a swivel with a mouthpiece at the other end.
It is used to enable the flameworker to blow into his bubble while
he works it in the flame.
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Burner
The
heat source of the flameworker. It usually runs on gas and oxygen
or air. It consists of a head that contains many orifices to distribute
and direct the flame, a body where the gas is passed up to the
head, and a valve assembly where the proportions of the gas/oxygen
mix and volume are controlled.
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| C |
Casing
The
application of one layer of glass over another, usually to achieve
a layered effect for graal or cameo glass.
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COE
Coefficient
of Expansion. The relative amount that a material will expand
when heated.
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Compatibility
Different
glasses that have the same COE are said to be compatible. This
means that they can be joined together while hot without breaking
apart when cool.
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Cracking
off
The
technique of breaking off the punti or rod that has been used
as a handle during the forming process.
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| D |
Devitrification
The
term literally means "un-glass" and means just that. Under certain
adverse conditions the elements at the surface of glass can break
down and leave a white powdery-looking deposit. Sometimes devitrification
can be eliminated by reheating, but often it cannot and it must
be removed by acid-polishing.
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Dichroic
Glass
that has been coated with a thin layer of metallic oxide. Dichroic
coatings transmit certain wavelengths of light while reflecting
others, creating an interference effect similar to iridescence.
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Didymium
A violet-colored
glass that has the property of being able to filter out the frequency
of light given off by glass as it is heated in an oxidizing atmosphere.
This bright light is called sodium flare and can be harmful to
the glassblower's or flameworker's eyes so didymium glass is used
to make protective eyewear for hot glass artists.
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Drawing
The
technique of pulling a piece of hot glass to make it narrower.
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| F |
Flame-annealing
A flameworking
technique where the finished piece is reheated in a bushy, relatively
cool flame to relax the stresses built up in it during the construction
process. This is usually used only on small pieces and is generally
regarded as a temporary measure for work that is to be properly
annealed later on.
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Flame-cutting
Any
technique where the flame is used to burn apart two pieces of
rod or tubing.
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Flameworking
Also
known as lampworking or lamp-blowing. The technique of heating,
melting and forming glass rods and tubes using a flame generated
by a burner or torch.
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Flaring
The
technique of spreading out the open end of a bubble or tube to
create a wider opening.
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Frit
Ground
up bits of colored glass varying in consistency from fine sand-like
particles to coarse chunks. It is used as an applied decoration.
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Fuming
The
technique of coating a rod of glass with a metal such as silver
or gold and then placing the coated rod in the flame while holding
the piece to be decorated jut just behind it. The metal is vaporized
and the resulting fumes condense on the relatively cool surface
of the piece.
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| G |
Gather
Any
mass of molten glass collected on the end of a punti or rod.
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Glass
An amorphous,
homogeneous material with a random, liquid-like molecular structure
formed by heating the raw materials to a temperature sufficient
to completely fuse them into a consistent material that, when
cooled, becomes rigid without crystallizing.
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Graphite
A crystalline
form of carbon, commonly used in glassworking tools because it
does not burn or stick to hot glass.
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| H |
Hard
Glass
A common
name for borosilicate glass. It has a COE of approximately 33.
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| K |
Kiln
A high-temperature
electric oven used for annealing, fusing or casting glass.
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| L |
Lathe
A device
that turns glass tubes at a consistent rate so that large pieces
can be easily formed into other shapes. The use of a lathe frees
the hands so that tools can be more efficiently utilized.
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| M |
Melting
point
The
temperature below which glass acts as a solid and above which
it can be shaped.
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Mold
A form,
usually made of clay, metal, or wood, that is used for shaping
glass.
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| O |
Optic
mold
A open,
cone-shaped mold with ridges on the inside that will impart a
pattern on the surface of a gather or bubble that is inserted
into it when hot.
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Oxidizing
An atmosphere
that is rich in oxygen and contains very little uncombusted gas.
Oxidizing atmospheres ten to affect colored glass that contains
metallic oxides in a different manner than reducing atmospheres.
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| P |
Paddle
A common
tool, usually made of graphite, used for forming hot glass.
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Point
A section
of tubing prepared for flameworking. It consists of a specific
length of full diameter tube with a tapered handle on each end
formed when the section is drawn off the original tube. The tapered
handles are also called "points", and can be opened to allow the
flameworker to blow into the tube to form a bubble.
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Pontil,
punti
A metal
rod used by glassblowers to make small gathers or to provide a
handle for an object while it is being made. Flameworkers use
glass rods for puntis.
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Powder
Finely
ground glass.
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Preheating
The
process of heating a glass piece from room temperature to a state
sufficient to prevent serious shock when plunged into a flame.
This can either be done in a kiln or in the backwash of a flame.
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Pre-mix
burner
Any
burner that mixes the gases inside the body of the burner prior
to ignition.
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| R |
Reamer
A tool,
usually made of graphite, that a flameworker used to help form
shaped form tubing.
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Reducing
An atmosphere
that contains a large quantity of uncombusted fuel that can cause
the oxygen molecules contained in the metallic oxides that color
the glass to react. This can cause a metallic deposit to appear
on the surface of the glass.
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Regulator
A device
for controlling the pressure of gas within a contained system.
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Rod
A length
of solid glass of a consistent diameter.
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| S |
Shears
A tool
used to trim off ragged edges or unwanted bits of glass.
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Soak
Holding
a piece of glass in the annealing oven at a particular temperature
to assure proper annealing.
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Sodium
flare
A bright
flame resulting from the reaction of an oxygen-rich flame and
the surface of glass containing sodium. It is protection from
this that is the main purpose of didymium glasses.
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Strike
Glass
that changes color when re-heated is said to "strike". The most
dramatic example of this are the borosilicate colors in the ruby
family that strike from a clear to deep red simply upon reheating.
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Swivel
A small
metal attachment for plastic tubing used in blowhoses. This allows
a flameworker to attach a blowhose to the end of a tube or point
so that he can blow into the tube while he rotates it in the flame.
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| T |
Thermal
shock
The
strain created by suddenly heating or cooling a piece of glass.
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Tip
The
working end of a burner that distributes the gases just prior
to ignition. Tips are available in different shapes and sizes.
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Tubing
Glass
that has been manufactured in a hollow form instead of solid rods.
Tubing is used by flameworkers to make bubbles instead of gathering
glass on a blowpipe.
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| V |
Vermiculite
An insulating
material to prevent glass from cooling too quickly, prior to annealing.
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