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Archive for the ‘Sculpture’ Category

Sandblast is a process wherein a stream of sand is driven by a jet of compressed air or by water against a surface. This creates a powerful abrasive action that can clean and abrade any surface put under the jet of these abrasive particles.

Abundant materials such as powdered quartz, emery, and iron globules are usually used as the abrasive materials in sandblast.

Sandblast is widely used for cleaning casting iron at foundries. Sandblast is also used for preparing different surfaces for painting, enameling and during galvanizing. Sandblast can also be used in cleaning stubborn grime that has accumulated in the stonework of most buildings.

Sandblast can also be used to create frosted designs on glass by placing a suitable stencil or pattern over a plate of glass and applied with a little sandblast. The jet of abrasive particles of the sandblast will strike the uncovered portions of the plate glass and create that frosted effect.

A sandblast operation can sometimes be a toxic undertaking. Sandblast operators can be exposed to several harmful particles such as lead or zinc that are important components of most commercial surface coatings.

Sandblast operators can also be exposed to the hazards of the abrasive particles being used. Without the proper safety equipment like goggles to cover the eyes and suitable protective clothing to shield against the flying particles, the sandblast operator and crew will be dangerously exposed to possible injury.

That is why there are several safety regulations to be followed before any sandblast operations.

Sandblast operators should use a standard issue air breathing apparatus while operating the machine. This will insure that the sandblast operator will have a steady supply of clean air supply amidst the workplace that will be filled with air contaminants during operation.

It is also important to consider that the hoses as well as the other equipment used to give the air supply to the sandblast operator should be able to deliver clean and contaminant-free air.

After operation, sandblast crew should only remove their air breathing apparatus when they are well away from the workplace. The sandblast particles can remain suspended in the air for long periods even after the operation.

It is also necessary for sandblast operators to wear coveralls that will provide suitable protection against rebounding abrasives during the operation of the sandblast.

Work gloves must also be used to protect the full forearm. Sand blast operators must also be able to wear the appropriate safety footwear.

It is also important to carry out the sandblasting operations in an area where the abrasive materials and other possible contaminants are safely contained and will poser no threat to other workers or to the public.

There are also some precautions that are to be observed when it comes to the sandblast machine. The sandblast pot where the abrasive particles are placed should be well grounded at all times.

It also must be provided with a safety shut down feature to further protect the sandblast operator. It is also important to remember to turn off the sandblast pot first while filling it with the abrasive particles to prevent accidents from happening.

The entire sandblast unit should be thoroughly inspected for possible defects before it is to be used. Sandblast nozzles should also be equipped with a safety control switch that will enable the operator to control the sandblast at the nozzle.

Following these simple tips will ensure the crew with a trouble-free sandblast operation.

Self-made fire pits can complement accessories gathered from home improvement stores. However there is nothing like constructing it in the original way. You can use plain landscaping blocks or stones. A few decide to use concrete blocks. Although this tends to get deteriorated with heat, however worth using as changing them is not costly. Drainage is an important part of domestic fire pits. You can dig a 3-4 inch hole 24 inches. Then fill it with gravel. This hole requires to be dug right in the bottom center of the pit. It is supposed to work like a sump and let the water drain. You have to dry-stack the stone first. The dry-stacking is as well useful for replacing cracked or broken stones. A few opt to cement the courses by laying cement on exterior half. This is considered useful for shielding the cement from high temperature.

Here are a few other things required here, retaining wall blocks, steel pit ring with tabs, metal grate, sand and gravel. Ring and grate are necessary things when constructing a fire pit at home. This can be found at home improvement stores or near garden stores. At times it is easy to buy these online. The width of the wall blocks used here can be 12 inches wide, 4 inches high and 8 inches deep. Put a substantial amount of sand and gravel in the pit.

Dig a hole at this moment. This hole is supposed to be 2 feet wider than the fire pit. Dig the hole around 7 feet diagonal to the fire pit. The hole is supposed to be round. To make it so, mark the circle. Dig out 1 foot of soil. Then dig for four inches of gravel plus four inches of sand. That layer is required to be compressed flat, next work with the base course of blocks. It has to be laid down and you have to level it carefully. The space out of the blocks has to be filled; you can fill it with gravel. The first course will be more or less buried this way; this in turn will strengthen the stone base.

Now you have to focus on laying more helpings of stone. At this point you will draw on the steel ring. The ring should keep the grill intact. This is done to confirm that each of the helpings is round with precise diameter. The ring has to be made vertical to each other and to the ground surface. If you notice that the center of your pit is roughly 36 inches in diameter- you will recognize you did well. At this point you can overlap the stone layers. In each of the helpings, you are supposed to leave 3-4 openings between stones. The openings are planned to let air to flow in and help the fire burn.

Given that by now the entire job is finished, it is now time to lay the last helping of stone. Ahead of the final helping is laid; the steel ring has to be placed in the spot. As a standard guides, a fire pit constructed this way can have 7 layers. Your pit constructed this way is supposed to be 24 inches high. For better results from your fire, you can take out a layer or two.

If you are you surprised on how to build a fire pit and to find out the steps involved in making a backyard fire pit that you will be proud of go on reading this article. As a homeowner, making an open-air space that your family can make use of all through the year is an excellent initiative. Unpleasantly cold summer evenings or fall nights don’t have to trail you indoors as soon as you’ve got a warm fire pit to get together. Here’s what you want to be familiar with to set up a simple fire pit bowl.

You will have to collect these materials to put together your fire pit, a few 3×8 lumber, galvanized screws and fasteners to fasten, sand, small gravel or rocks, cement, a steel fire bowl, miter saw, drill for making holes, screwdriver.

Make use of the 3×8 lumber to construct a structure for your fire pit measuring 60×60 inches square. Complete your structure by finishing with four more pieces of lumber and using it to build an attractive border all along the top of your structure. You will need to take care your border has mitered trimmings with the intention that the corners have a smart looks. As soon as the border is finished, make use of the screws to fasten it to your structure. You can coat your frame with color, if you want. Take care that it is fully dried up earlier than you move to the next step.

Lay the structure in the area where you would like your fire pit to be positioned. Take care that the structure is level. Load the structure with about two-thirds of sand filled in it. Level the surface with a smooth leveling tool. At this instant you will put the fire bowl in top of the sand. Be certain to put a little additional sand up alongside the bowl to hold it in position. Now put in the small gravel or rocks until the sand is fully covered.

At this time you can begin to enjoy your backyard fire pit. However, it’s essential to be safe as soon as you are managing an open fire. You will need to take care that you haven’t positioned your backyard fire pit very near to your home. You should set the fire pit no less than 12 feet away from your home. This as well applies to your garage, shed, fence, or other things on your home. As it comes to your backyard furniture, keep some tables and chairs as a minimum four feet further than the fire pit.

You may have to buy a screen to contain stray sparks from flying out. At all times be certain that the fire is fully extinguished earlier than you leave it, as well. Take care of the weather conditions; if it’s very breezy outside, avoid lighting the fire and leave it for other occasion. Now that you are familiar with how to build a fire pit, you can simply decide on a personalized design, which will make a balmy open-air atmosphere in your own back garden or patio.

Guidelines of making Plaster craft

Plaster craft is a complex process unless you are aware of its ins and outs. Given below are a few guidelines of making plaster craft.

Step – 1:

Cover your work surface with an old newspaper or a vinyl peace. As you may see from this photo plaster casting is a bit messy, so it is essential to protect your countertops.

Step – 2:

Check the mould to ensure it is clean and dry. Any dirt might show on the finished casting.

Step – 3:

Many moulds cannot sit flat on the counter, therefore, it is important to give them support while using. The most simple process is a zip lock bag filled with a few pounds of rice. Rice bags are convenient to pack and store when not being used and are made of common materials most people find handy. A box of sand will also work well but it is more difficult to store it when not being used.

Step – 4:

The surface tension of the water tends to trap air leading to pinholes in the finished casting. Airid is a product meant to break that surface tension, reducing the chances of trapped air. Spray or wipe a thin coat of Airid into the mould.

Step – 5:

Wiggle the mould down onto your rice/sand bag till it looks level. You are now ready to mix plaster.

Step – 6:

To find out how much plaster will it hold fill the mould with water. It is the exact amount of water you will need. Add a bit more and weigh it on scale.

Step – 7:

Plaster should always be added to water and never vice versa. Sprinkle it in slowly to allow it to absorb water.

Step – 8:

Let the mixture remain undisturbed for 2 minutes so the plaster absorbs all water.

Step – 9:

For coloring, pigments should be added now.

Step – 10:

Utilize a potato masher to mix thoroughly for about a minute. Small amounts can be mixed with a stick.

Step – 11:

Pour the plaster in a corner of mould and let it flow across the complete mould. On deeper moulds, pour it down the side of corner to avoid entrapped air.

Step – 12:

Once the mould is poured, wiggle it to dislodge any air which may have remained in the mould.

Step – 13:

Periodically feel the mould. When the mould is warm to touch, the plaster casting may be removed.

Step – 14:

Gently flex the edges of mould to break sides of casting loose.

Step – 15:

Hold the mould just above the rice/sand bag. Use pressure gently to take out the casting.

Step – 16:

After casting is out, set the mould to be cleaned.

Step – 17:

Utilize a knife to cut the sharp edges off the back of the casting. For fast drying it should be put where it gets air from all angles.

Step – 18:

When fully hardened, most of the plaster will flake off or breakout the plaster.

Step – 19:

Flex the blade of the plaster blender to flake the dried plaster off.

Step – 20:

Wipe off tools and moulds for final cleaning up.

Step – 21:

If you utilize a rice bag any drips may be removed by flexing the bag. For sand box, just pick out any plaster that has fallen on sand.

Step – 22:

Pack up your moulds, tools and plaster. Throw away the old newspaper with which you had covered the working area. If you had used vinyl piece, dust it and wipe with wet cloth.

Ernest Race the textile and furniture designer was recognized as one amongst the most creative and challenging personality of mid-century design. His furniture designs included for dining, lounge and furniture for case, which was completely, constructed using metals and other improvised materials. His famous works included B.A 3 chair, Antelope chair, Heron chair, Purple chair and so on. His designs were contemporary and liked by all and were in constant production.

The metal furniture designed by Race was enthusiastically bought by the private firms as well as the contractors of the market. He has his best orders for chairs and tables of 1500 in number for troop-ships. Gradually his orders increased day by day, mostly placed by the private sector. Later Race opened his own showroom which was stylish, decorated with plain walls on which coconut mats were hung. Race with his outstanding abilities, demonstrated the essentials of assessing the market needs against the restriction of materials.

The famous B.A3 chairs were preferred for the interiors of a ship. These were constructed out of five interchangeable materials which consisted of sand cast and polished aluminium. He used ingenious paneling which is provided with highly polished laminated plastic and with scratch resistant wooden finish. He covered the honeycomb shaped edges of the table, using aluminium in the form of ribbon. This B.A 3 stood on four raised tapering legs which seem to appear light and contrasting.

The Great Britain festival gained more fame for the works of Race. His works like the Springbok, the Antelope chair were on the display in the exhibition. The Antelope chairs had high aesthetical appearance.

Race continued to design the furniture using steel rod which had an appreciable demand in market. He developed the rocking chair in the year 1948, after being inspired from a 1850s Winfield rocking chair made of metal. A special feature of the rocking chair was pretty interesting; it had a seat with a back made of undulating steel wire.

In the year 1955, Race introduced the Heron armchair, which was a very creative internal work, constructed with welded steel rod. He replaced the use of wooden frames with the steel rod and also latex foam which was of light weight. This furniture provided at most comfort.

Race Rockers, was a metal rocking chair designed by Race in the year 1948. The chair is a linen union, and was manufactured in three colours. The race rocker was recently auctioned for a sum of £464.12.

Isokon Penguin Donkey 2 was one of the best utility furniture. It was basically a desk like thing, an ideal place for books, CDs, magazines, newspapers, remote control and so on. This furniture was the second design in the Penguin Donkey series of furniture.

The Neptune chair, renowned furniture was designed by Race in the year 1953. This was made of Beachwood and webbing. This had a large scale sales world wide.

Race’s contribution to the world of furniture design was a significant one, which led to the evolution of modern furniture designing.

Man’s use of fire can be traced as far back as one million years ago. The fires then were built on the ground. While the ancient people were inside their huts, smoke accidentally escaped through holes in the roof. Approximately half a million years ago, fires were already built on a solid hearth and holes were deliberately made in the roof so smoke could exit.

Fires were traditionally placed in the middle of the room to allow maximum accessibility and heat output. The advancement of the first two-storey buildings led to the fireplace being relegated to the outside wall. The only material available then for building the floor of the second storey was wood. Obviously, it was unwise to build a fire on a wooden floor, so the fireplace was moved into a cut-out in the wall. The flue was placed horizontally so extraction of smoke was poor. Smoke would frequently have blown into the room. In the end, they discovered the principle of the chimney.

The means of using wood to heat homes and offices is almost as old as dirt. It can be traced back to the 1700s when Abraham Darby used procedures of smelting, where it was found out that iron provided a cost-efficient way of producing heat.

It was during the Victorian age when fireplaces began to grow popular. During this time, people discovered that aside from producing heat, fireplaces added a hint of elegance. It somehow gave homes a comfortable and traditional environment. Through the years, housing designs evolved and so did the fireplaces, along with the technology. Fireplaces changed and became more fashionable, offering sand casting systems. This provided a chance for makers to create even more superior designs.

In spite of all the changes and the advancement, the basic fireplace is still made up of two components – the surround and the insert. The surround part of the fireplace is composed of the mantle and sides. It is typically made of wood, granite, marble, and sometimes iron. The insert is the part of the fireplace where the fire is burned. This part is constructed using cast iron and is frequently adorned with stylish tiles of different colors and designs.

Benjamin Franklin had an important part in the discovery of fireplaces. He found out that fireplaces lose a significant amount of heat through the wall. It gave him the idea to make the first freestanding firebox, which came to be recognized as the Franklin stove. He put his first stove in the middle of the room, which solved his problem on how to look for means to heat a room. The outcome of the experiment was that the whole room was heated completely and equally. His other finding was that by using heavy cast iron, the heat continued being produced even when the flames had died out.

Still, with all his excellent discoveries, Franklin’s effort had a defect. The hitch was that air cannot be drawn in. This is because the smoke was vented from the bottom. David Rittenhouse, from Philadelphia, decided to utilize Benjamin’s invention but innovated it by putting in an L-shaped stovepipe as a means of moving the air through the fire and then emitting the smoke out through a chimney. This add-on proved quite successful. It was in the late 1700s that these freestanding stoves were being used all over the country. Although David Rittenhouse made the stove a success, people still identified it by the name Franklin Stove.

It is not too farfetched to predict that in the future a complete building will be built from a computer. Similar technology has already begun to be used by the industrial design and manufacturing industries. One of the best-known and oldest technologies is called Stereo Lithography, because it involves a laser beam moving through a vat of ultraviolet-sensitive liquid polymer, which follows the contour of a digital 3D model. The beam strikes on a layer of ultraviolet-sensitive liquid polymer, and then the thin layer is solidified. The laser will keep repeating the same process from the bottom to the top of the 3D model. A temporary framing support for the model is required, because the process is from the bottom up. Stereo Lithography machines are manufactured by 3D Systems Inc., and they are also known as Stereo Lithography Apparatuses (SLA). The final model usually requires a little bit of sanding, and it is inappropriate for an office setting because this process produces toxic fumes. The following is a list of processes that may assist the automation of the building industry. These existing technologies can immediately assist the building industry; however they do require some modification to suit individual building types. It should be noted that these manufacturing processes are crucial to the development of building automation. Computers can produce precise results, while manual labor is imprecise. The direct digital manufacturing process can reduce errors and make digital building components affordable. The original prototype is always costly, but the cost can be reduced to a bare minimum by using rapid prototyping processes.

Rapid prototyping (RP) is a digital modeling process, which is a real physical model of a component (in prototype form) that is entirely created directly from a 3D CAD drawing. RP systems generate quick prototypes by constructing an additive and layer-by-layer process that is driven by 3D CAD data. RP is also known as desktop manufacturing or free-form fabrication. RP machines require STL data files, which are generated by the CAD system. An STL file is a data file format designed specifically for rapid prototyping machines. Any rapid prototyping system can use the STL file from any type of 3D CAD system that outputs the STL data. RP machines operate quite differently than typical CNC machines. RP machines are subtractive in nature, because they join together liquid, powder and sheet materials to form complex forms. Using layer-by-layer technology, RP systems fabricate plastic, wood, ceramic or metal objects based on several cross-sections from a 3D CAD model.

RP cannot be mistaken by rapid manufacturing (RM) or rapid tooling (RT); however, all the above mentioned processes involve 3D CAD files. RM is a rapid manufacturing process. RM is an ultimate process that manufactures parts directly from a computer. The benefits of any rapid processes are that fewer steps are required to achieve the final result and that

The original prototype is always costly, but the cost can be reduced they are much faster than the traditional methods. According to Wohlers, some companies are beginning to use rapid prototyping technologies to manufacture finished parts. Most of these applications are geared to small quantities of parts, because there are still some technical difficulties for RM in reaching the production capacity of injection molding, die-casting, or sheet metal stamping at the time of this publication. These technical difficulties are: inferior surface finishes to production molded parts; inadequate dimensional accuracy and repeatability; durability and cooling efficiency; small limited part sizes; and the time and expense associated with removing excess resin and performing post curing operations. “These applications are proving that rapid prototyping can be suitable for production in terms of speed, material properties, accuracy, and surface finish. Moreover, rapid prototyping of mechanical CAD designs is well established and will continue to grow. Soon many other applications will follow suit. Indeed, organizations will rely on the technology for sculpture, architecture, mold flow analysis, molecular modeling, forensic analysis for solving crimes, and a variety of uses yet to be conceived.”1

RAPID PROTOTYPING
Stereo Lithography Apparatus (SLA) – This is the oldest (discovered in the late 1980s) and most common technology. It involves a laser beam moving through a vat of ultraviolet-sensitive liquid polymer which follows the contour of the digital 3D model. The beam strikes on a layer of ultraviolet-sensitive liquid polymer, and then the thin layer is solidified. The laser will keep repeating the same process from the bottom to the top of the 3D model. A temporary framing support for the model is required, because the process is from the bottom up. Stereo Lithography machines are manufactured by 3D Systems Inc. The final model usually requires a little bit of sanding, and it is inappropriate for an office setting because this process produces toxic fumes. SLA is simple, fast and accurate.

Idea Applications

* Prototype or Presentation Model a quick, fast, and concise process for conveying the design intent. SLA is inappropriate for creating the final form, because the end result is highly fragile.
Object 3D printing – this process uses ink-jet technology with photo polymer resins. The ink-jet like head drops fine deposits of resin while a UV lamp cures these droplets immediately. Object 3D printing is also a layer-by-layer process. Objects created by 3D printers are highly detailed and accurate. No sanding is required, because the object is cleaned with a low-pressure water jet in the process.

* Appropriate for architectural model

* Form and fit analysis

* Concept and presentation models

* Sales and marketing samples

* Tooling patterns

Z Corporation’s 3D printer – The Z Corporation’s 3D printer works by creating physical 3D models directly from digital data, layer by layer. A part can be printed at the rate of 25mm (1″) vertical per hour. It is fast, versatile and simple comparing to other similar systems, allowing architects/engineers to produce a range of concept models and functional test parts quickly and inexpensively. The system is ideal for an office environment or educational institution, providing product developer’s easy access to a 3D Printer. “A 3D CAD file is imported into the proprietary system software. The software slices the file into thin cross sectional slices, which are fed to the 3D Printer. The 3D Printer creates the model one layer at a time by spreading a layer of powder and ink-jet printing a binder in the cross-section of the part. The process is repeated until every layer is printed and the part is complete and ready to be removed.”2

Idea Applications

* Ideal for conceptual models, architecture models, and functional testing prototypes

* Require Z-bond solution to make the component stronger.

* Can be used to make strong, high-definition parts and is the material of choice for printing color parts.

* Can be used to quickly fabricate parts that can be dipped in wax to produce investment casting patterns.

* Can be used to create sand casting molds for non-ferrous metals.

* Has been optimized for infiltration with Z-Snap epoxy to create
parts with plastic-like

When the search for a rapid tooling solution begins, it is common to use traditional tooling techniques as the benchmark. The goal becomes the replication of all the quality of a cut tool while slashing the delivery time and expense. With these standards, the options become limited. These imposed limitations can make it best to seek out a tool shop that is extremely fast and efficient at building cut tools in aluminum or steel. In the evaluation of projects, Accelerated Technologies often finds that a machined tool is a far superior solution.
Under the original, narrow definition, rapid tooling has limitations in many areas. These include:

* Tool life

* Accuracy

* Surface finish

* Resin selection

* Tool configuration

* Cycle time

* Part size

Each available rapid tooling solution presents limitations in at least two of these areas. When the strengths and weaknesses of the processes are presented, many elect to use traditional methods that may require more time. It certainly will be a dream comes true if technology brings down cost of buildings. Shopping for a designer house will be one of the choices open to everyone, not the privilege of a few. A 10 to 15 year recycling time for a house will be appropriate, because the recycling cost will be lower than the renovation cost.

Fast prototyping cannot replace our current building practice, but at least it will help to construct a mock-up to improve the design. It is a known fact that a full-size building mock-up is necessary to eliminate errors and the need for future design modifications. Fast prototyping can accelerate the mock-up process, bring down the cost, and speed up the final construction time.

Full-size building component prototypes are not yet in production, because they require detailed connections and some modifications. It is not hard to imagine, that in the near future an entire house will be manufactured by an LOM machine or other RP processes directly. Such a notion is exciting and will revolutionize the building industry. Rapid tooling is a powerful process that can definitely make the building process faster, cheaper, and better.  If you find this article interesting, and want to find out more about how emerging technologies change the field of architecture.  Please go to Amazon.com or barnsandnoble.com to check out Mr. Chang’s new book- Making of Digital Forms: A Study in Emerging Technologies in Architecture.

Footnotes
1) Wohlers, Terry, Computer Graphics World, November, 2001

2) ZPrinter 310 Plus Brochure, www.zcorp.com, March, 2008

With sand casting the mold is broken up after each casting operation, but with the process known as gravity die casting, the mold also called a ‘die’ is manufactured from metal, and can be utilised a giant number of times. This suggests that the die is far more costly to make, than an expendable ‘one use only’ mold. An intermediate technique gets use from semipermanent molds, which are made of gypsum plaster or fireclay, which may be employed continually for a controlled number of castings. With gravity die casting, the most widely used materials for die-making are cast iron, steel, and heat resisting alloys of iron. For some specific purposes other materials are used to manufacture the dies, and these can include, aluminum. Copper or graphite. A metal die can produce smooth castings with a clean surface, and a very high dimensional accuracy. These castings require awfully little last machining or other finishing treatment. The service life of metal dies can vary in terms of the amount of castings it can produce, and this relies on certain considerations such as the casting material, the thermal metal shock resistance of the die material, the temperature at which it is poured, and the casting technique employed.

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Many different details need to be considered when designing the pattern from that the die is made. For example the pouring-gate system and risers have to be considered so that the walls of mold permit a quenching action upon the molten metal so it van harden more rapidly than in sand casting. Also the die must be supplied with channels at the joints and air vent holes to allow air from the hot metal to escape from the interior of the die. The die must also be built so it won’t restrict the shrinkage that occurs, when the metal cools. Shrinkage can present difficulties when designing the cores which form the casting. Usually the cores are made of steel or special alloys, and sometimes compressible sand or shell cores are used.

To prevent the casting metal from sticking to the die, the die can be given an internal coating of chalk, clay, or bone ash with water glass as a binder. This mixture can be applied to the die by spraying, brushing or immersion.

With straightforward castings the molten metal may be poured in at the top. It should be designed to allow the molten metal to flow quickly without turbulence into all elements of the die. For metals with low melting points the die is frequently heated to stop premature solidification, and for metals with a high melting point, the die may be artificially cooled after each casting operation.

Slowly moving or angling the die while casting can reduce turbulence and enable the metal to flow more smoothly, especially when heavy castings are being produced. For awkwardly formed castings, a vacuum may be applied to help the filling of the die. Slush casting, is a technique used for producing decorative or hollow castings : the molten metal is poured into the die, and when a solid shell of acceptable thickness has formed, the remaining liquid is poured out.

Although die castings are less expensive than sand castings, the die tooling is dearer, and a perfect number of castings have to be produced to make the process cheap.

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Jewelers who specialize in custom designing often use the lost wax casting method to create one-of-a-kind rings, charms, pendants, or other specialized items out of precious metals.

First the jeweler may sketch an idea on paper, especially if he or she is working with a client.  When the diagrammed sketch is approved, the jeweler then fashions an exact replica of the finished item in a soft, pliable wax.  The wax pattern, or maquette, is fitted with a stem called a sprue, which will create an exit for the wax when it is burned out.

This wax form is weighed to determine the amount of metal that will be needed.  It is then attached to a base and fitted with a tumbler that holds the mold material, which is plaster mixed with water to a cake batter consistency, called investment.  It must be free of bubbles before pouring into the tumbler, so it is placed in a vacuum to remove all the air.  The investment is poured into the tumbler and then taken to a kiln to have the wax burned out.

A jeweler’s centrifuge machine is the tool that injects the liquid metal into the mold.  The mold is taken from the kiln and placed in a holder that has a hollow arm attached to a cup that lines up with the hole in the mold. The pre-measured metal is placed in this small crucible, and then heated with a torch until it is liquid. 

The pin is then released on the centrifuge, and it spins rapidly around while the liquid metal is forced into the tumbler and mold. Once the spinning stops, the tumbler is removed from the centrifuge with tongs (it is extremely hot), dipped into cold water, and the plaster cracks and falls off of the metal inside.

At this point, the beautifully designed object created on paper does not even slightly resemble the blob of metal in the jeweler’s tongs.  This is because the base (or button) and the sprue are now metal like the rest of the design, and must be sawed and ground off with a jewelers’ Dremel tool, which is an instrument much like a dentist’s drill.

Much fine sanding and shaping is done with the Dremel and its attachments, and gradually the original design emerges.  Jewelers’ rouge puts a nice patina on the finish, and after much polishing, the piece is now ready for use.

Having a custom-made, jeweler-designed ring, pendant, charm, or other special item is something to be proud of, since it can define who you are, what your interests are, or what is important your life.

If you burn coal on sand or just ashes from a previous fire, it would be nearly impossible to burn. Coal requires air under the fire or it will not ignite. Wood will burn without a grate but very imperfectly. There is a small amount of oxygen (air) in wood. Just enough to make a smoldering fire to create a great deal of creosote and smoke in your heating appliance, smoke pipe and chimney. To burn wood or coal on sand or just plain steel is similar to burning garbage in a barrel. If you ever try it you will have a very smokey fire because there will be a lack of oxygen (air). Unless you cut some holes at the bottom of the barrel.  Many outdoor boilers use this (non) technology. That is one of many reasons why they smoke so much.

To prove the above theory to your satisfaction, you can try the following if you have a wood-burning fireplace. Remove the grate. Start a wood fire on the firebrick or steel hearth. It’s not only hard to get burning, when it does start to burn, the flame will be uneven across the wood and it will be a smoky flame. For a second test, place the wood in a steel box with only the top open. That will cause even worse results than the first test.  Now place the wood in a fireplace-designed grate. Nice fire, right?  It is because you have provided air under the grate.

Consider burning on a heavy cast iron grate with an adequate amount of air available to the firebox from below the grate, regardless of what type of wood or coal burning appliance that you choose. Adequate air under the grate helps assure you of a reasonably clean fire with reduced smoke or creosote coming from the flame. A wood fire will last a little longer without a grate at the cost of a dirty fire and more smoke and creosote build-up on every part of your wood or coal burning system, including the firebox, smoke pipe and chimney.

If you want an even cleaner fire with less creosote and soot buildup in the system, provide a secondary air source above the flame. This is known as secondary air. If you provide 80% of the air from below the grate and 20% of the air from above the flame, you can increase the efficiency of the wood burning appliance by as much as 40%. This is because 40% of the energy produced by a wood or coal fire leaves the initial flame in the form of unburned gases. By igniting these gases, you not only get a cleaner burn with less soot and creosote, the efficiency of the wood or coal is increased dramatically, thereby stretching your savings on the purchase of wood or coal.