Metal shaping
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Shaping metal is basically as simple as shinking or stretching it to achieve the required shape. | Shaping metal is basically as simple as shinking or stretching it to achieve the required shape. | ||
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| + | BUCKS AND PATTERNS | ||
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| + | Before any metal can start forming, its good to know the exact shape of the piece one wishes to create. | ||
| + | Bucks can be made using anything from styrafoam to plaster and anything between that a pattern can be pulled from. | ||
| + | Below is a picture using "Burt" buck strips of metal and foil tape to create the shape required. Chicken wire was used to hold the metal strips in place in order to tack and tape them together. The buck was then slathered with bondo to check the actual shape and to pull the best possible pattern from. | ||
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| + | Once the buck is ready, a flexible shape pattern can then be made. The pattern starts with low stick masking tape. Plastic stretch wrap and transfer tape can also be used. | ||
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| + | The low stick tape is then covered with fiberglass reinforced packing tape applied in two directions. This helps it maintain its shape when removed. | ||
| + | Once the pattern is ready it is pulled off carefully and then the back is dusted with baby powder or similar item to stop it from sticking to itself. Reference marks can be added to the pattern before adding the packing tape. The pattern can also be cut into managable sized pieces before removal from buck. | ||
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| + | USING THE PATTERN | ||
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| + | The pattern can be placed on the sheet stock and traced around for the rough cut. Adding an inch here is a wise decision as the piece will be shrunk and stretched so having a large enough piece is crucial. However, hand shaping metal is quite a workout on the arms so having too much extra material can be a waste of time as you will be shaping metal that will be cut off later. | ||
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| + | With a bowl shaped piece the edges can be shrunk on the stump first. The pattern is then placed on the part. One then pushes down on the flexible pattern to find hollow spots underneath the pattern. This is the key to the pattern. Finding the hollow spots below tells you that either those areas need to come up more or that the edges need more shrinking. | ||
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SHRINKING | SHRINKING | ||
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Shrinking metal can be done using a stump and wooden or plastic mallet. A set of tucking forks can also be used but this process can be slow and tedious. A reciprocating machine such as a Pullmax with thumbnail dies can also be used to shrink metal rapidly. This is not a machine for a novice though. Learning to shrink metal by hand is said to be the best way to see how it reacts throughout the process. | Shrinking metal can be done using a stump and wooden or plastic mallet. A set of tucking forks can also be used but this process can be slow and tedious. A reciprocating machine such as a Pullmax with thumbnail dies can also be used to shrink metal rapidly. This is not a machine for a novice though. Learning to shrink metal by hand is said to be the best way to see how it reacts throughout the process. | ||
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[[Image:DSC05346_(Small).JPG]] | [[Image:DSC05346_(Small).JPG]] | ||
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STRETCHING | STRETCHING | ||
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Stretching metal can be done on a shot bag with a wooden, plastic or steel mallet. The bag is made of leather and filled with a material such as lead shot or sand. Plastic injection molding pellets have been used for this as well. | Stretching metal can be done on a shot bag with a wooden, plastic or steel mallet. The bag is made of leather and filled with a material such as lead shot or sand. Plastic injection molding pellets have been used for this as well. | ||
Metal may also be stretched over a hollow such as the cut out of a stump or even a piece of pipe. In the photo above, one corner of the stump has a 3" dia hole for stretching metal. Shrinking a piece of metal around the edges will result in a bowl like shape. After shrinking the edges to the maximum amount allowed by this process, it then becomes necessary to stretch the center area of the piece to achieve the radius required. | Metal may also be stretched over a hollow such as the cut out of a stump or even a piece of pipe. In the photo above, one corner of the stump has a 3" dia hole for stretching metal. Shrinking a piece of metal around the edges will result in a bowl like shape. After shrinking the edges to the maximum amount allowed by this process, it then becomes necessary to stretch the center area of the piece to achieve the radius required. | ||
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REVERSE CURVE | REVERSE CURVE | ||
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Stretching the edges of a panel only and not working the center at all will achieve the classic potato chip shape. This is called the reverse curve. The stretching can be done by holding the edge of the sheet over a cutout in a stump and applying some severe hammer blows. The photo below shows a wooden mallet with a small radius and a panel that has been stretched over the 3" dia cut out. | Stretching the edges of a panel only and not working the center at all will achieve the classic potato chip shape. This is called the reverse curve. The stretching can be done by holding the edge of the sheet over a cutout in a stump and applying some severe hammer blows. The photo below shows a wooden mallet with a small radius and a panel that has been stretched over the 3" dia cut out. | ||
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ENGLISH WHEEL | ENGLISH WHEEL | ||
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An English wheel (ewheel) can then be used to smooth out the lumps created from the stretching or shrinking processes. If too much pressure is exerted by the ewheel on areas that were shrunk, the material will start to stretch changing the shape. If too much pressure is exerted at the stretched areas, the metal will be stretched even more and change the shape. | An English wheel (ewheel) can then be used to smooth out the lumps created from the stretching or shrinking processes. If too much pressure is exerted by the ewheel on areas that were shrunk, the material will start to stretch changing the shape. If too much pressure is exerted at the stretched areas, the metal will be stretched even more and change the shape. | ||
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