Thermometers Produce Scales Aircraft Painting Luxury Chocolates
You can sense the difference between hot and cold, but a thermometer puts a number on it. The concept is simple-- heat causes liquid to expand, forcing it up a glass column with a scale attached to it. Italy's galileo came up with the idea in 1593. Incredibly, these century-old thermometers can still tell the temperature. But modern versions are a bit more precise. To make one, they clamp glass tubing onto a carousel. As it spins, torches heat the center of the hollow glass, while below, the operator pumps air into it. This causes the melted glass to blister. They break the tubing at the blister, creating two tubes with funnel-shaped openings. They anchor a shorter glass cylinder on a turntable and suspend one of the funnel-mouth tubes above it. The tubes spin in concert as torches melt them together. The funnel ensures that the melting doesn't close the hollow tube. Another torch now aims further down the cylinder. It seals the end and shapes it into a ball. To test a sample of the production run, they heat the entire length of the tubing. This creates vacuum pressure so that when they place the open end in liquid wax, the tubing sips it up like a straw. By watching the liquid ascend, they confirm that the thermometer fills as it should and has the right dimensions. Next, the glass tubing swirls on a carousel as flames and forced air work together to form a longer blister. Again, they break the tubing at the blister. This blister creates openings that allow them to snake a narrow, hollow wire through the tubing, joining the two sections. Flames melt and seal the glass around the wire. This is called a glass-to-metal weld, and it creates a more flexible thermometer. They cool the welded glass and wire on a conveyor. Next, they turn on a vacuum pump for several hours to pull the air out of the wire and tubing. This draws the blue liquid wax up, but this time, it's not a test. The wax is a nontoxic alternative to mercury that will expand and contract with changing temperature. The thermometers now travel through chilled alcohol, shrinking the blue liquid down to the closed end of the thermometer. As the tubing turns, flames follow the top end to melt and close it. A heat gun below then drives the liquid up the tubing, and the air pressure creates a bubble in the end that was just closed. This bubble will be the thermometer's expansion chamber. They plunge the thermometers in ice water to calibrate the bulb liquid to 32 degrees fahrenheit. They scratch the glass at that mark. Next, the thermometers warm up in a bath set at 200 degrees fahrenheit. The blue liquid shoots up, and they make another scratch. They align the two scratches in the thermometer with markings on a printed grid. The distance between the two scratches often varies, so by measuring against this grid, they can calibrate the thermometer. They then match the thermometer with the corresponding scale. They install the top section of the thermometer in a case which can be metal or plastic. They then choose the appropriate scale and slide it between the glass tubing and case. They wrap part of the wire capillary around a joint and then cap it. The sensor bulb of this thermometer will be used to gauge the temperature inside industrial piping. So they protect it with a metal sleeve called a bulb chamber. A glass window slides easily into the grooves of the casing. A plastic cap is the finishing touch. And now these thermometers are ready to gauge the highs and lows of industrial processing, and they're sure to measure up to expectations. Much of what you buy in the produce department of your supermarket is sold by weight. So the store usually hangs a scale at the end of the aisle on which you can weigh your purchase before heading off to the checkout. This is typically a type of scale with fairly simple mechanics. Internal springs spin a pointer to the correct weight mark on a dial. The weight of produce hanging in the pan pulls on a pair of springs inside the scale. They move the various internal components that turn the pointer to the corresponding weight mark on the dial. To make the scale's frame, a press stamps a steel plate five times, progressively cutting and bending it into the final frame shape. A washer goes into each steel spring. They turn it up or down to adjust the spring's tension. That's how they'll calibrate the scale later. The top part of each spring will bolt to the frame, and the bottom part to this slider-- a long metal component with weight markings. Next, they attach a component called a rack to one end of the slider, securing the screw tightly with thread-locking fluid. The rack's teeth will mesh with this pinion gear and turn it. They install one end of the pinion into the frame. Then they screw on a metal bridge to support the other end. They insert the slider with the rack attached through the bridge. Now when you pull on the slider, the pinion turns. Next, they attach the springs to the frame and slider. Each spring in this imperial scale supports up to 20 pounds, making this a 40-pound scale. When weight pulls on the springs, they move the rack, which turns the pinion, which rotates the scale's pointer. A press stamps out the dial face from a steel plate. After painting it white, they print on the markings with a silk-screen press. They insert a spring to prevent the rack from slipping on the pinion. Then they put the face over the bridge so that the pinion protrudes through a hole in the middle. A guide helps them align the face so that the zero will be in the right spot. Then they tighten two screws to attach the face. A press stamps the pointer from a thin sheet of aluminum. Using a special tool, they twist the end, forming a thin tip that won't obscure the fine line to which the pointer's pointing. Next, a coat of red paint so the pointer will stand out against the black-and-white face. Once the paint's dry, they mallet the pointer onto the pinion. Now they hang the pan on the scale and turn a little screw in the slider to adjust the pointer to zero. This ensures the scale will weigh just the produce rather than the produce and the pan. Now they calibrate the scale. To do this, they load it with weights to full capacity, which is 40 pounds for this scale. If the pointer doesn't indicate 40 pounds on the nose, they turn the washer in each spring to adjust the resistance. Then they adjust the pointer back to zero again. This is what they call a double-dial scale, meaning it has a face and pointer on each side. They install the second dial on the opposite end of the pinion so that the two pointers move in unison. They close up the space between the two dials with a strip of white plastic. This sash ring, as it's called, has grooves for the dials and for the transparent plastic cover that goes over them. Hanging scales can have dials or digital readouts, and they come in a wide range of capacities, from your common 20-pound, or 10-kilogram, grocery model, to heavy-duty 600-pound, or 272-kilo, scales designed to pull their weight in industry. The stresses of flight are hard on an aircraft's paint job. Ice, rain, and other environmental factors can soon make an aircraft look travel-weary. Regular paint jobs are just the ticket when it comes to keeping up appearances. They also help maintain the integrity of the airframe. Problems may lurk beneath the old paint of an aircraft. Stripping it off can expose weaknesses in the aluminum skin. They brush on a powerful chemical solution. The paint bubbles off, baring the aluminum and any small holes or dents in it. They seal the windows and doors and wrap sensitive components like antennas to protect them during stripping and pre-painting. Back to those flaws on the exposed aluminum. A production manager flags any damage or corrosion with blue tape. A technician then mixes a two-part aerodynamic filler. He works quickly because the compound will harden in minutes. He spreads the filler on the defects flagged by the production manager. The repair job smoothes the surface for painting and makes the airframe stronger and more aerodynamic. This aircraft has been primed and sanded. Now technicians blow off all the dust. They also wipe it down with adhesive cloths. This intensive cleaning is crucial. The plane has to be squeaky-clean or the paint won't adhere properly. Next, they prepare an additional primer. They spray it on areas that need more coverage and around parts that will get a lot of wear. They then mix polyurethane paint with various catalysts and activators. It's a special aircraft blend. Jets can be jumbo-sized, of course, so they often prep and paint a section at a time, sometimes on different days. They're now working on the fuselage and tail. Respirators and full-body gear protect them from the hazardous fumes as they work from the top of the aircraft down. A warm, low-humidity environment is essential to allow the paint to cure properly. And they'll adjust the paint formula to compensate when conditions aren't optimal. An aircraft usually gets two to three coats, resulting in a high-gloss finish. While it dries, a technician demonstrates for our camera the process of painting stripes onto an aircraft. He maps out the paint scheme with tape, then peels away some of it. He spray-paints the exposed sections. He peels off more tape and then covers the freshly painted stripes with protective paper so he can spray another color onto the plane. He pulls back the final pieces of tape, and this job passes with flying colors. They do some final detail work to make sure the lines are clean and crisp. After all, appearances count in the high-flying world of international travel. Even very tiny imperfections won't be tolerated. Using fine-grit sandpaper, they make them disappear. It can take four weeks and 1,800 person-hours to repaint a large jet. And when it comes to price, the sky's the limit. The least expensive jobs cost tens of thousands of dollars. So the customer has the final say. The handshake means this plane is ready to model its new look on the runway. Bite into a luxury chocolate, and you'll get a taste of one of the finer things in life. Each one tastes different from the next, and it's that element of surprise that keeps us coming back for more. Of course you could consult the index on the box, but that would spoil the fun. Ever since chocolate was discovered, people have had a craving for it. Today's luxury chocolates take our addiction to a whole new level. They add marshmallow cream and lots of pure butter to a mix of sugar and corn syrup to whip up some buttercream chocolates. Water, vanilla, and a special yeast enzyme complete the recipe. The enzyme will enhance the creaminess. They tuck the buttercream between ridged rollers, which shape it into creamy columns. A wire slices them into bite-sized morsels. They tamp the buttercreams to a uniform height. Chocolate oozes up through the slats of this conveyor to coat the bottoms of the creams. Then it's on to a cool surface to solidify. Next, the creams travel through two curtains of chocolate while being coated on the bottoms again. A worker uses her fingers to make a symbol on the top. It's a clue as to what's inside. A trip through a 24 1/2-foot-long cooling tunnel hardens the chocolate, and it's a feast for the eyes. You can look, but don't taste. These chocolates are headed to the stockroom. Now production takes a sweet turn as they cook up a caramel filling. They add sugar and salt to water, followed by corn syrup and a lot of heavy cream. They fire up the burner and turn on the mixer. They add butter to enhance the flavor. As the mix comes to a bubbling boil, it caramelizes. Then they kill the heat. Otherwise, the next ingredient, pure vanilla, would evaporate. They apply a nonstick substance to a big pan, then pour the caramel into it. They leave it to set overnight. The next day, they divide the caramel slab into squares. They feed the caramel squares into a device with circular knives. It's called a gang cutter, and it slices the squares into strips. They turn the sliced square sideways, and it goes through the gang cutter again to create caramel cubes. They dust the caramels with starch so they won't stick to each other as they go through the chocolate-coating system. And that's how they get the caramel in the chocolate. To make cordial-cherry chocolates, they load the cherries into a revolving pan. They add sugar crystals, and as the cherries roll around, they get an even coating. Along with the sugar, these cherries have been coated with a special enzyme. It will turn the sugar to liquid over the next 10 days for a juicer cherry taste. The enzyme effect is why the cherries get an extra coating of chocolate. It creates a solid shell that contains the sugary liquid. And now they're ready for cherry-picking chocoholics. Each box of chocolates contains 18 to 20 different varieties. Since they make three to four flavors a day, it can take up to a week to produce one of these luxury assortments. Of course, they'll be devoured in no time at all. For the customer, it's one sweet deal.