Curling Stones Refrigerators Aluminum Baseball Bats Opalescent Glass
Today on "how it's made"... Curling stones... Refrigerators... Aluminum baseball bats... And opalescent glass. The sport of curling is a combination of shuffleboard, billiards, and bowling on ice. Players aim a large stone at a target while trying to knock the opponents' stones away from the target. As the stone glides along the ice, team members sweep brooms in its path to control its speed and trajectory. Curling stones are made of granite, but only two quarries in the world-- one in wales and one in scotland-- produce the unique type of granite that's required, a fine grain and free of quartz. This unique stone has three times the impact resistance of regular granite. The quarry tries to avoid traditional blast mining because that fractures the stone. Instead, they locate flaws in the rock face and pry chunks off of it with an excavator. This chunk weighs about 20 tons and is the size of a small car. The next step is to divide it into more manageable slabs using a thick cable cutter with abrasive rings made of diamond particles. A large pulley system moves the cable against the rock at high speed, and the diamonds slowly wear through the granite. Avoiding flaws and weak points, workers trace circles the size of curling stones on the best-quality areas. The cut slab then moves inside the quarry building, where this core drill's diamond cutters bore right through the slab, excising a blank that will become a curling stone. The blanks weigh almost 60 pounds apiece. Workers lift them out with an industrial-strength suction cup then transfer them to a container bound for a curling-stone factory in canada. There, a drill bores a channel a little over a half-inch wide right through the center. This is for attaching the curling stone's handle. But that's still a long way off. First, this machine has to carve the blank into the shape of a curling stone. The machine's curved arm is lined with diamond cutters. It shapes half the stone, then workers flip the blank over so it can finish the other half. The next machine carves out a pocket in the bottom of the stone. This will hold a high-resistance insert of extra-fine-grain scottish granite that will extend the curling stone's life. After lining the pocket with epoxy, the insert is positioned. A hydraulic press expels any trapped air and holds the insert in place until it firmly bonds. Next, a grinding machine, following a template, makes a center cup in both the top and bottom of the stone. Curlers can attach the handle to either cup, depending on which granite surface they want gliding on the ice. Workers bolt the stone to a spinning polisher and buff the surface with five progressively finer grades of diamond abrasive pads. Then they blast the side with tiny glass beads. This pits the surface to better distribute impact force, preventing the side from chipping as it strikes other stones. Running the top and bottom over coarse sandpaper gives the stone more traction on ice. The finished curling stone weighs in at 40 pounds. The factory molds the stone's handle from durable impact-resistant plastic. This computer-guided engraving machine can embellish it with any name or logo. Paint is applied to the recessed areas to make the lettering or design stand out. Finally, the finished handle is bolted through that center hole drilled earlier. From the quarry to the factory to the ice, this beautifully crafted curling stone is ready for competition. When we return... The cold, hard truth about refrigerators. Before refrigeration, people stored foods in underground cellars or shacks filled with snow and ice. Then in the early 1900s, a french inventor developed the first machine to cool and preserve foods at home. The modern refrigerator comes in countless styles, sizes, and colors. Manufacturing begins with coiled sheets of steel. Just one of these coils produces hundreds of fridge exteriors. The interiors are made from rust-resistant aluminum lined with an acrylic shell. A shearing machine slices the steel into pieces for the exterior top, back, and sides. Then each one goes into a computerized punch press that makes the holes for running various wires. A brake press forces the steel against a forming die to create edges. Next, workers place the pieces of the refrigerator's outer shell in an assembly jig, which holds them firmly together. Now for the fridge's interior. A vacuum-forming machine heats a sheet of plastic and shapes it against an aluminum mold. Then a router carves off all the excess plastic. The freezer half of the refrigerator slides perfectly into the metal outer shell, and the fridge side follows. Copper tubes, filled with heated gas, are laid along the outer edge where the door contacts the fridge. The gas prevents moisture buildup. A precut face frame goes onto the assembly. Then foam is injected into the cavity between the interior and exterior shells. This foam not only insulates the refrigerator but gives it structural rigidity, as well. This evaporator plays a key role in keeping things cool. It draws the heat out of the freezer and its contents. Next, the electrical control panel goes into place. It connects to a maze of wires and, eventually, a microprocessor. With the freezer side almost complete, the fridge side gets its evaporator. Next comes the refrigerator doors. Two compressors pump fluid and gas through the various tubes inside. This component, called the radiator, dissipates the heat collected from the food. Workers attach the expansion valves. These allow the pressurized liquid coolant to expand into a cold gas that circulates through the refrigerator's tubes. Copper tubes are soldered to the compressor. Later, they'll be filled with refrigerant. Temporary quick-connect valves allow the system to be charged with inert gas to check for any leaks. The fill hoses are connected, and the gas blows in. Inspectors use this wand to check the tubes for escaping gas. If there's a leak, the gauge spikes out of the specified range. Refrigeration occurs as cold gas in the evaporator coils pulls heat energy from inside the fridge. The compressor then changes the gas back to a liquid while the radiator dissipates the collected heat. The expansion valve turns the liquid back into a cold gas, and the cycle repeats. With a charging gun, workers inject refrigerant gas into each tube then weld the ends of the tube shut. Now for the finishing touches, starting with the refrigerator handles. Drawers for fruits and vegetables slide right in-- so do the rest of the premade shelves and compartments. Finally, an adhesive logo goes onto the door. Built-in, stand-alone, double-door, or traditional, the refrigerator keeps our food fresh and cool, just the way we like it. Up next... A factory that tries to hit a home run every time. On today's baseball diamonds, the ping of the aluminum bat is rivaling the crack of its wooden predecessor. The pros still use traditional wood, but outside the major leagues, the metal bat is a definite hit. Lightweight and durable, the metal bat has some definite advantages over wood. Production begins with aircraft-grade aluminum rods. These rods are sliced into short chunks called blanks. The blanks are loaded into a lathe with a computerized drill. The drill tunnels through the center of the blank as it spins. Then the blank undergoes what's called impact extrusion. With 300 tons of force, a shaping tool bores into the hole in the blank, stretching it to more than twice its length and giving it the basic taper of a baseball bat. The stretched bat blanks now tumble into a big, perforated drum. The drum is lowered into a tank of soapy water. As it turns, water flows through its holes, washing away any oily residue. And now, for a real heavy hitter. This forming tool delivers 400-ton punch through the center of the bat blank. The aluminum stretches around the tool to the full length and shape of a baseball bat. A technician measures the bat to confirm that it's completely straight. If it's not, she applies a little hydraulic pressure to bend it into shape. This is a critical step because even a slightly crooked bat could throw the player off his or her game. Next, the bat goes into another computerized lathe. As it spins, a blade lops off the bat's end, cutting it to size. Another tool threads the inside for the endcap. The bat is locked into a holding device, and a circular saw trims the handle end. Now that the bat has been correctly sized, it's time for a vigorous sanding. This gets rid of any small defects and roughs up the surface so paint will stick to it. They use heavy-duty paint because baseball bats have to stand up to a lot of abuse. The sanded bats go into a silk-screen machine that applies the trademark. Then it's over to the decal department. The decals are dipped into a solution that activates the glue, then they're stuck into place. Now it's back under the paint gun for a clear coat of polyurethane. The plastic endcap is press-fit into the hollow barrel. An aluminum knob slides onto the handle end, and the assembly goes into an automated welding machine that fuses them together. Now for the grip. Synthetic leather is wrapped around the handle to provide a nonslip surface. And a little vinyl tape finishes the edge. From a solid little chunk of aluminum to a hollow metal baseball bat, this powerhouse is ready to hit one out of the park. Coming up... The hot secrets behind opalescent glass. Glassmaking dates back more than 40 centuries. But in the late 1800s, glassmakers created something new-- glass that was both milky and translucent. They called it opalescent glass. Like its namesake, the opal gemstone, its beauty lies in the way it magically catches the light. Opalescent glass is a semitransparent glass in either a solid color or a swirling mix of hues. Glass makers create it by melting minerals, including silica sand... Soda ash... Dolomite... Limestone... And fluorspar. Adding recycled glass helps speed up the melting process and stretches costly raw materials further. The mix is colored with pigments, in this case, cobalt oxide, which gives a distinctive blue tint. A hoist then lifts the raw ingredients called batch to a double-chambered mixer. Ingredients flow from end to end between them, thoroughly blending the batch. The blended batch now goes via wagon to the beehive-- a furnace that contains 12 ceramic pots. The furnace worker shovels the batch into a pot to melt at a searing 2,600 degrees fahrenheit. He pushes any spills back into the pot. Then to control the temperature inside, closes up the pot's mouth. 24 hours later, workers scoop out the glowing molten glass. With only seconds to spare, they hurry to the mixing table, keeping the glass in motion to prevent it from cooling unevenly on the way. It's critical they cool off the ladles between each use or the next scoop of glass will adhere to the ladle's surface. The ladles they use vary in size, holding between 4 and 40 pounds of molten glass. Workers pour as many as five different ladles at once to make a single color. The mixing table is where the magic happens. The table worker picks up one gather of burning molten glass, then another, then skillfully blends them together using a steel fork. He then flips the molten glass into a rolling machine, evening it out as it squeezes through the rollers. Out comes a sheet about 6 feet long and 1/8th of an inch thick. Every 90 seconds, workers fill their ladles with 2,000 degree fahrenheit molten glass. Mixing it on the table helps cool it and blend the colors. The table worker separates the glass sheet from the table surface, forcing out any trapped air bubbles and further cooling the glass. The sheet now goes into a lehr-- an oven that hardens the glass, then cools it evenly to prevent cracking. From there, it's on to the trimming table. Workers wear protective clothing and thick gloves to handle the razor-sharp edges still hot to the touch. Cutting the glass sheets is a delicate, two-person job. They must work in sync to keep pace with the sheets that keep on coming. A single pot produces about 25 sheets over 24 hours. That's 300 sheets a day from just one 12-pot furnace. Using a carbide-tipped cutter, the workers score the glass, then snap apart the pieces--  standard 32-inch square sheets. They set aside the excess glass to remelt in a new batch. Finally, the sheets are loaded into crates for shipment all over the world. Just look how artists use opalescent glass to create a feast of pattern, color, and light. Like a painting, only far more fragile.