How is stretch glass made?

This series of pictures were taken at the Fenton Art Glass Company factory where glass with the stretch effect is still being made. The process used today has not changed from the original!

We wish to thank Fenton Art Glass Company for the chance to document the process.

A batch of glass is first mixed and melted in a "hot metal pot" or tank. The first step in making press-molded glass is to take a "gather" of the molten glass from the pot on the end of a gathering rod.
The gather is taken to the pressing area and the molten glass is allowed to drip into the mold. The press operator cuts off the piece of glass after visually determining that the correct amount of molten glass has been placed in the mold. The cutting sheers cool the cut end of the glass producing a "cutoff mark" which is often called a straw mark in the finished product. By pushing the cutoff tail to one side or another, the press operator can often lessen the visibility of this mark.
A close up of the gather being cut over the mold.
With the new glob of molten glass in the mold, the press operator shoves the mold assembly under the plunger. The plunger forces the glass into all the parts of the mold. Some plungers have patterns which produce "optic" designs inside the piece.
Close up of the plunger (left) and the press with the plunger lowered into the mold (right).
After pressing, the plunger is lifted, the mold is pulled aside and the top ring is lifted off. The mold is then opened (molds may be two-, three-, or four- piece molds which refers to the number of sides that are hinged together) and the glass is "turned out" by a "turning out boy" (yes, they call this person a "boy" no matter who it is!
The hot piece of glass is taken over to another area where it is placed in a "snap." The snap is a metal rod fitted with an end plate that contains jaws that are the same diameter as the base of the glass piece. By pressing the rod onto the floor, the jaws are opened. The jaws are covered with lime (which appears white in the picture) to keep the hot glass from sticking to the steel.
The "snapped up" piece is taken to another blast furnace which has numerous ports for reheating the glass. These are called "glory holes."
After being reheated, the piece is taken to the "doping" booth to be sprayed with a metallic salt solution. The solvents instantly vaporize leaving a microscopic layer of metal which produces a shiny iridescent effect. (At this point, the piece would be considered carnival glass - doping after being shaped and no further shaping after being doped)
In stretch glass, the doped piece is reheated a second time - this is the major difference between carnival glass and stretch glass! The underlying glass expands more than the metallic coating and the magic of the stretch effect is formed. The stretch marks can be further enhanced with additional shaping.
While the doped and reheated piece will have the characteristic stretch effect, the effect is further enhanced by shaping, especially expanding the opening. True carnival glass will be shaped BEFORE doping.
Pressed glass, especially pieces that have been reheated, doped and shaped, has considerable internal stress, and this stress must be relieved or the piece will shatter into hundreds of pieces! The pieces must be put through an annealing lehr for several hours. This lehr is basically a long oven with a conveyer belt. The temperature of the glass is first raised and then slowly cooled to release internal stress.
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