Blowing

12 lines that use it

What it looks like on the line

• Stained glassForm the sheets. A glassmaker blows a gather into a cylinder or spins it into a crown, or molten glass is poured on a table and rolled flat. Flashed sheets carry a thin colored layer fused to another color or to colorless glass.
• Bottled waterForm the bottles. PET plastic has replaced glass for most single-serving bottles, because it is light and resists breaking. Preforms are blown into bottle shape, often right at the plant.
• Incandescent light bulbBlow bulbs from a ribbon. A continuous ribbon of glass rides a conveyor through a furnace. Aligned air nozzles blow it down through holes in the belt into molds below. A typical machine makes 50,000 to 120,000 bulbs an hour.
• Zip-top bagBlow a tube with ridges. The melt exits a ring die and is inflated into a bubble of film. Slots in the die let two thickened ridges form on the inside, one for each half of the zipper.
• Neon signBend over a ribbon burner. The bender marks the tube against a pattern laid out on a fire-resistant sheet, heats each spot in a propane flame, and bends it gently. Blowing into the open end restores the original diameter, and each bend is checked against the pattern.
• Glass jarFlip and blow it out. The parison swings upside down into the final mold. Compressed air or vacuum pushes the glass out against the walls until it takes the shape of the jar.
• Stainless steel water bottleInflate with water pressure. The tube is clamped in a water expander and filled with water under enormous pressure. The wall swells outward into a bottle shape, with no bottom yet.
• Plastic bottleStretch and blow. A rod pushes the soft preform lengthwise as high-pressure air balloons it into a bottle-shaped mold. Stretching in both directions lines up the molecules and strengthens the walls.
• Glass bottleBlow the rough shape. In the blank mold, compressed air or a metal plunger forms the opening of the bottle, called the finish, and a small hollow body called the parison. The "blow and blow" method is used for narrow necks, and "press and blow" is used for jars.
• Foam cupPuff the beads with steam. Polystyrene beads with pentane trapped inside meet steam in a pre-expander. The heat softens the plastic while the pentane turns to gas and swells each bead into a closed-cell foam sphere.
• Glass bottleFlip and blow to size. An arm swings the parison upside down into the final mold. A last blast of air blows the glass out against the mold walls. One machine has 5–20 identical sections, and each section can make one, two, three or four bottles at once.
• Snow globeMake the dome. Snow globes were traditionally glass, with heavy lead glass domes in the early days. Plastic became available in the 1950s, and modern domes are made in either.