Metal Casting Zone Info Blog

Posts Tagged ‘method’

I’ve seen on the internet where people use a pile of sand packed tightly to impress the object they want to cast and pour the molten metal into the hole in the sand. Even with fine sand, this does not produce the smoothest surfaces and sometimes the sand becomes embedded in the casting. I knew someone who cast pewter statues and he used this green foam-rubber looking stuff to make molds. Anybody know what I’m talking about?

Before crafting handmade jewellery two things, casting and making of jewellery by hand, must be understood. This will help you to decide whether making of jewellery by hand is worse or better, than casting.

The handcrafted jewellery is designed by hammering, bending, twisting and soldering the metal in desired form. For instance, while making a plain gold wedding ring the jeweller will start off by having a lump of gold metal in an undefined shape and will melt it down. Then he will pour the melted gold into a steel container which will harden the liquid for giving desired shape. The liquid will be turned into a thick bar. Then jeweller will roll the piece up to a time that he will finally get a long flat piece. After that he will cut down the pieces in a length that can be easily fit in customer’s finger. In the next stage he will hammer the piece to give a shape of ring and will join the both corners to create a ring. After that, he will give it a nice circular shape and polish it. Then recommended gems or crystals will be fitted into the ring. Now the gold wedding handmade ring is ready. This whole process might take one hour or little more. The whole process will start again as mentioned, if another ring is required to be made.

So the hand made jewellery piece will take hours or may be days to craft while casting it will take minutes for casting numerous identical pieces. In hand made jewellery the labor cost is a main factor. On casting, only the cleaning is required and nothing else and short time is spent in casting method.

For casting, in the jewellery trade the Lost Wax casting method is used as main method of casting. In this method, a master piece is prepared first and this master piece can be used to make unlimited copies of the jewellery item. In casting method large number of rings are made at one time but in hand made method only one piece is made at one time. So it can be said that the piece of handmade jewellery is stronger and heavier because of the techniques used like hammering and filling which make the piece hard and qualitative.

In casting sometimes the bubbles remains inside and missed by the manufacturer, which make it a less quality product and less durable. Nowadays this kind of problem can be easily controlled by highly sophisticated equipments but it could happen. The casting method can also be said a duplicating method by which a manufacturer copies number of rings of a piece.

So comparing both methods, the hand made piece of jewellery can be a unique thing and an expensive one. Casting method is cheaper and many people can enjoy the same product. Handmade jewellery is long lasting, durable and harder as compared to jewellery made with the casting method.

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.

The most fundamental of all definitions to ceramic casting is: It is a process used in order to shape ceramics. It is known in many companies like those for tableware and teapots. Even computer parts, heat engine sections and recuperators find this process very helpful. The development is also very essential to a lot of technological areas.

Ceramic casting utilizes a wide range of materials like stainless steel, bronze, cutting tools and plastic casts to form impellers. Other items appropriate in the process are epoxy, silica, metal, water, zirconia and even wood. In order to make the process enhanced, surface quality, uniformity and density should be attained. Know more about the different techniques to make the method more functional to some industries.

Methods behind ceramic casting

Two of the most popular methods in ceramic creation are slip casting and ceramic shell casting.

First method – slip casting. This is a technique making use of slip and liquid clay. It is being poured into a cast created from plaster of Paris. Traditionally, it utilizes a potter’s wheel cast. The wheel is very vital in making symmetrical alterations to any part. This is said to use pure ceramic powder thus causing this ceramic casting method the most popular among other techniques. In fact, you no longer have to spend on chemical additions just to perform and complete the process.

2nd method termed as ceramic shell casting. This ceramic casting skill is popular in the development of metal pieces. The net casting method is performed with a mixture of refractory items, silica and zirconia. Subcategories for this skill are wet dripping and dry coating. The method results to dimensional steadiness for aerospace and liquefied metal casting companies. With the automation procedure, other objects such as wax patterns, slurry mixers and powder beds are employed for dipping.

Apart from these two techniques, there are other ceramic casting skills. Several of those included in the list are coil creation and soft and hard slabs. Threading procedures are utilized in accomplishing these skills. Threading is a ceramic casting process that utilizes animal and artificial wool fibers to make several layers out of an existing object.

Have you ever looked at a piece of your jewelry and wonderd just how the jeweler made it? How do they create the fine detail in a piece of jewelry and what about the smooth swirling shapes. The fact of the matter, is that every piece of fine jewelry starts out being made from wax. Its called the “lost wax” casting method and it is amazing to see from start top finish.

The first step is to create the piece out of sculpting wax, which is the same wax that dentists use to make crowns for peoples teeth with, because dentists use the lost wax method for casting gold crowns. Then the wax piece is then encased in a can that is filled with wet plaster and allowed to cure and dry. After the can of plaster with the wax piece in has dried it is then placed in a hot kiln so the wax “piece” in it can melt and burnout of it.

What is then removed from the kiln is a hunk of plaster with the hollow shape of the wax piece left in the middle of it. The jeweler will then place the hunk of plaster in a device that spins around and uses centrifugal force to push molten metal down into the hollow shape inside of the hunk of plaster. It will then be allowed to cool and then the plaster will be chipped away revealing the piece of jewelry where the wax piece once was.

It will be cleaned up and then any details will be carved into it or welded onto it using a jewelers delicate tools and a jewelers torch. If any stones or gems are to be added to it, that will be the last step that is taken. It is then given a final polish and it is done. This method of making jewelry has not changed in thousands of years.

I’ve seen on the internet where people use a pile of sand packed tightly to impress the object they want to cast and pour the molten metal into the hole in the sand. Even with fine sand, this does not produce the smoothest surfaces and sometimes the sand becomes embedded in the casting. I knew someone who cast pewter statues and he used this green foam-rubber looking stuff to make molds. Anybody know what I’m talking about?

The lost-wax method is a method of casting metal that has been in use for six thousand years. Virtually unchanged since used by the ancients, the method is used today to create such pieces as bronze sculptures, custom silver jewelry, dental work, or even auto parts.

“Cire perdue,” or lost-wax, is a method of casting metal that has been in use for over six thousand years. In essence, it involves the pouring of metal into a mold created from wax, resulting in complex forms otherwise impossible to create. The lost-wax method is used today to create such pieces as bronze sculptures, a silver pendant, a gold dental crown, or even an alloy auto part.

The lost-wax method is the best way to create intricate designs in metal, it is commonly used for making elaborate custom jewelry. Technology and tools have advanced of course, but the method is essentially the same as it was when used in Ancient Egypt.

The artist will first sculpt his masterpiece out of clay, wax, or another malleable material. Then, the model is encased in plaster or fiber-glass to create a mold. An inner mold will often be created at this time as well, by pouring liquid rubber around the model. This preserves the finest of details, important because when the plaster is broken apart, the original model is usually destroyed.

When the two halves are placed back together, the result is the master mold. Inside is empty space, a “negative” of the original. Hot wax is then poured into the space to coat the sides. Depending on how large the piece, a number of coatings may be needed. The hollow wax copy, an almost perfect replica of the original, is then removed (multiple copies can be created at this time).

The wax copy is then “chased” using heated tools to remove the seams where the mold came together. Each copy is carefully “dressed” to hide any remaining imperfections.

Next, “sprues” are attached to the piece, which are basically small wax rods that will ultimately result in tiny tubes for metal to flow in, and air to flow out.

The wax replica is then coated in ceramic material and fired. At this point, the wax melts out, thus the term “lost-wax.” Negative space now remains (as well as the small pathways left by the sprues). Finally, molten hot metal can be poured into the mold into the exact shape of the original model.

The metal piece is also chased to remove any marks left by casting, and detailed to perfection. If in fact a bronze sculpture, this is when the final act of adding the color occurs.

The lost-wax method can be used with any material that will disappear (melt or burn away) and leave an empty mold. For example, some automakers make engine-block models out of a synthetic foam which will vaporize when heated. This complex process allows for the most minute detail to be fashioned into the most delicate of metals. This makes it ideal for custom jewelry.

When working with small pieces like jewelry the process slightly differs in that metal cannot just be poured into a such a tiny mold. Instead, liquid metal is injected into the limited space by centrifugal casting (a machine that uses centrifugal force) or vacuum casting (uses atmospheric pressure).

Artisans like Jewelry John use the lost-wax method to etch inspiration into their heirloom jewelry. They specialize in hand-crafted silver bells and silver pendants, and with intricate detail they convey emotion in beautiful custom silver jewelry. Such complex designs would not be possible without this ancient casting method.