Glassblowing

Glassblowing As I See It
By Roshaun
Class of 2004, Wilson High School

Gathering
Until the glass is collected it rests in a complete liquid state in a crucible, which sits enclosed in an insulated brick furnace.  The temperature inside this oven reaches temperatures of over 2200° F.  For the majority of the glassblowing process, the furnace is sealed off by a door, which can be easily opened to gain access to the glass inside.

The artist reaches into the glass with a 5-foot long hollow steel pipe called the blowpipe.  By slowly and evenly turning the blowpipe in the glass, the artist is able to capture the glass on the end few inches of the steel.  At first the artist is faced with the challenge of evenly turning the pipe so the glass, with honey-like consistency, won't drip off the end.  Later in the process, as the glass cools, the artist is no longer concerned about the glass falling to the floor but instead with the piece falling off center.  Although the glass does not stay in complete liquid form for very long, it is constantly in threat of warping due to uneven turning while hot.[Back to top]

Coloration
Color adds an important element to glass.  Color can change the whole mood of the glass because of the unique way light travels through this medium. 

Coloring techniques range from quite simple to extremely elaborate designs.  Some examples of coloring may include rolling frit (tiny chips of colored glass) on the outside of a piece, or using a solid color encased in clear glass to give the illusion of solid color.  The artist can wrap a bit of color around the outside of a piece with the use of a threading wheel, which helps to make it even.  Using pulled and decorated cane, called "Latticino," will create a distinctive pattern in the glass, while using glass tiles, or "murinis," may create a more complex coloring pattern.  Additionally, the application of gold leaf can be used for surface decoration, while simply filling the furnace with colored glass instead of clear will allow the artist to set a tone for their work.[Back to top]

Blocking
Instead of using the marver, the artist chooses to use a wooden block soaked in water to shape the glass after the second gather.  By using the wooden block, the artist maintains greater controls than marvering on a steel table.  The block can be used to shape the sides and the bottom of the glass and, in the hands of the artist, will produce a nice even shape from which to make the glass piece.

Glassblowers use several different size blocks as well as wet folded newspaper to shape hot glass.  Using newspaper grants even more control by squeezing and shaping the glass in the hands of the artist.[Back to top]

Blowing
Surprisingly enough, the actual blowing is a very small part of the process.  Artists need to be aware of how hard and for how long they are blowing into the mouthpiece of the blowpipe.  Too much air will make the piece too thin, while too little air will cause the piece to be thick.  Temperature always plays a crucial role in evenly blowing out a bubble.  If one section of the glass in hotter than another, then that section will blow out more rapidly than the cooler area.

The primary goal in blowing at this point in the process is to create a small air bubble inside the glass.  At this step, it is important that the piece not be too thin.  When the artists takes a second gather of glass, the heat and weight of the additional glass may collapse or warp the bubble.[Back to top]

Glory Hole
The glory hole is another high heat oven used in the glassblowing process.  Typically, it stays around 2200° F.  Most glory holes have opening doors in front, this allows the artist to use the same glory hole for larger and smaller pieces.  A yoke usually sits in front of the glory hole's opening. The yoke contains two ball bearings, which allow the artist to simply set the blowpipe down and turn evenly while inside the glory hole.

Making the Jack-line
Once the final gather has been taken and the piece is starting to take form, it is important to prepare the glass to eventually be removed from the blowpipe.  The bubble inside the glass piece begins where the end of the blowpipe touches the glass; this is called the neck of the pipe. Eventually that neck will be the top opening of the piece, also known as the lip.  The jack-line will need to be redefined throughout the process.  The jacks are the primary tools for glass artists.  Shaped like a pair of tong-like scissors with a flat handle, jacks are used for shaping, opening the lip, applying bits and various other activities.[Back to top]

Blowing Out the Shape
Once the neck is defined and the glass temperature even, the artist can begin to shape the glass as desired.  Blowing out the piece is an important part of shaping it.  By blowing into the mouthpiece of the blowpipe, the glass fills with air and expands.  Again, the artist must be careful not to make the shape too thin or too thick; thin walls will result in difficulty during reheating, while leaving the glass too thick will contort the aesthetics of the final glass piece.[Back to top]

Flattening the Bottom
By using the flat handle of the jacks, the artist flattens out the bottom of the piece.  This is what the piece will sit on when finished.  The artist must take care to create a universally flat bottom.  If the bottom is made off center, the piece will sit crooked when finished.  Additionally, the bottom must not be too thin or it runs the risk of cracking during the end stages of the process.[Back to top]

Bringing the Punty
A small gather of glass is taken on a thin solid steel rod called a punty.  The gather is then marvered so that there is very little glass at the end of the steel.  This bit, or punty (Italian for "bridge"), is intended to act as a joiner for the new pipe and the glass piece.  By connecting the punty to the piece the artist can then take the piece off the blowpipe.

The punty is designed to break off the pipe one the piece is complete.  Ideally, the punty will not leave a large scuff when it is broken off the piece.  Furthermore, since the punty is designed to break off easily, it is very delicate for the remainder of the process.  Even slightly hitting the pipe could cause the glass piece to fall and shatter on the ground.

Jacks are used to steady the artist's hand as the punty is applied.  The punty must be connected to the center of the piece in order to keep the piece straight for the rest of the process.[Back to top]

Chilling the Neck
Once the punty is connected to the glass piece, the neck needs to be severed from the blowpipe.  First, the artist needs to chill the neck in order to create a clean break.  The artist applies cold water along the neckline to create tiny fractures in the glass. Once the neck is scored and chilled, the artist will give a slight tap on the blowpipe with the back of the jacks.  The vibration will cause the neckline to crack and then the piece will be supported solely by the punty.[Back to top]

Knocking Off the Piece
When the piece is finished, the artist must separate the glass from the punty by tapping the seam between the punty and the bottom of the piece.  Occasionally, the artist uses water to chill the punty, which aids in the breaking process. 

When the piece is completed, it is broken off the punty and placed in an annealer (an "oven" set at about 900° F), which slowly cools the glass to room temperature.  A piece made today will be cool enough to cold work (grind and smooth the bottom) and take home tomorrow.[Back to top]