What is flask: application, varieties, how jewelry is made with it

Opoka is a rock composed of opal silica . Usually these are dense, light (volumetric weight 1.1-1.8), sonorous, porous (stick to the tongue) rocks with a conchoidal fracture. They can be easily drawn with a knife, but cannot be rubbed with fingers. The flasks are actually compacted tripoli. In natural outcrops they are usually painted in light colors. In deeper horizons they are almost black in color, which is replaced by dark gray and light gray during weathering. These varieties can be observed even within the same outcrop. There are flasks originally painted in light colors. Often the opalescent substance of opok transforms into chalcedony. Poorly preserved remains of diatoms and sponge spicules are present. Sand particles composed of quartz, feldspar and mica, and especially clay particles, as well as glauconite, also take part in the structure of the flasks.

Opoka Bakansky quarry

How to make an aluminum casting mold

There are several aluminum casting techniques that are used in production on an industrial scale. But if we are talking about work at home, then the most acceptable way is to pour liquid aluminum into homemade molds. This is the technology we will talk about.

Before understanding the nuances of casting, it is advisable to remember some of the characteristics of this metal. Aluminum melts at a temperature of about 660 ° C (depending on its purity), and boils at 2,500. Another feature that needs to be taken into account is rapid oxidation upon direct contact with air.

There are quite a lot of different “engineering solutions” that can be implemented when casting aluminum yourself at home. “Craftsmen”, knowing its characteristics, select the necessary devices and materials themselves.

One of the main problems is what and how to make a mold for pouring. This is where people who have no practical experience most often stumble.

Therefore, we will consider only one of the simplest options, since it is unrealistic to cover all the methods in one article.

Let's start with what you need to prepare for casting:

Aluminum scrap

Each of us has encountered this metal. But has everyone noticed that, for example, aluminum wire can be different? One bends easily, like plasticine, and the other is harder, less pliable. For casting, it is advisable to choose the one that is softer, since such a material, relatively speaking, contains less oxides and more “pure” aluminum.

Gypsum

The easiest option for working from home. Its best brand is sculptural (marked “G – 16”). But it has yet to be found, and the cost of such a high-quality product is quite high. Therefore, in domestic conditions, white gypsum (designated “G - 7”) is more often used, which is not in short supply. It can be purchased at any specialized store that sells building materials.

It is very similar in appearance to alabaster, and the two can easily be confused. In addition, the seller, not knowing why the buyer needs plaster, may offer this “analog” instead. In the construction industry, materials often replace each other, since many of their characteristics are similar. But alabaster is definitely not suitable for making molds! This needs to be taken into account.

Wax

This material is mentioned in almost all recommendations for do-it-yourself metal casting. Indeed, this is the best option, but only if we are talking about the manufacture of small parts. Pure wax is quite expensive, and there is no point in buying it in large quantities. Moreover, it is unlikely to be used again.

In practice, you use ordinary candles, which are found in any household goods department. Whether they are stearic or paraffin is not important. The quantity depends on the dimensions of the required part, the “blank” of which will be prepared from them.

You'll need a few more things as you go along. This will become clear when considering casting technology, and the choice of specific materials depends on the ingenuity and capabilities of the craftsman.

Melting containers

You can also melt candles in a regular tin. But for aluminum, the cookware needs to be stronger, since it will have to be heated quite strongly.

Heat source

What can I use? Muffle furnace or homemade crucible/gas forge. The main thing is to achieve the required melting temperature. As for the last “device” (crucible), it is clear from the picture how it works. You just need to take into account that the brick must be fireproof.

When using a sufficiently powerful stove to heat materials, it is necessary to include some kind of temperature regulator in its power circuit (if it does not exist). Such modernization will save time, nerves and electricity. It is enough to install a simple rheostat or an adjustable transformer (LATR). Otherwise, you will have to constantly turn on/off the device so as not to “drive” the temperature.

Making a blank

The task is to melt the paraffin and pour it into a mold with certain linear parameters. After it has cooled, it is easy to cut out an exact copy of the required part from the hardened mass. The easiest way is to take a shoebox. In principle, such “formwork” can be easily made from cardboard or plywood, securing the entire structure with adhesive tape.

Features of work

The poured mass cools down for a very long time, and this process should not be forcibly accelerated. Hardening should occur naturally, then the structure of the blank will be uniform throughout its entire thickness. You will have to wait at least a day, since the top hard crust is not yet an indicator that the paraffin inside has hardened.
The material used is characterized by significant shrinkage. In other words, in the central part of the mold the mass will “sag” somewhat during the cooling process. When calculating the dimensions of the required workpiece, this should be taken into account and paraffin should be poured with some reserve in volume.

Since you will have to manually cut out a part from a finished sample, it is clear that in the absence of experience (and perhaps even ability), it will not be possible to do everything accurately the first time, especially if you need to cast something of a rather complex configuration. But a rejected “blank” has only one path – to be melted down.

In order not to waste time, it is advisable to prepare two of them. If the first one is spoiled, then with the second one, taking into account the experience gained, the work will go more successfully. Considering that candles cost pennies, this will not “hit your pocket.”

Mold making

There are enough recommendations for its preparation. One simple way is to make it from plexiglass. This “aquarium” is assembled by fastening cut pieces of hardboard using plasticine. They also seal all joints.

Making a part template

A “blank” is placed at the bottom of the “aquarium”. To prevent it from moving during the process of pouring the solution, it is fixed with the same plasticine.

It should be taken into account that all other work is done quickly, since the plaster sets well. But this material is not used in its pure form. Its mixture with sand of the smallest fractions (50 to 50) is used. Otherwise, water will remain in the gypsum mass, which will begin to evaporate after pouring aluminum. This will cause pitting in the finished part.

The mixture is diluted to a medium-thick sour cream, after which the solution is loaded into the mold. You need to cook it so much that the “blank” is completely covered with it. In this case, it is not worth saving on material, especially since its price is low. To remove air bubbles, if there is no vibrating table, the mold must be shaken thoroughly by hand.

After the poured mass has hardened, the “aquarium” is dismantled. All that remains is to remove the paraffin from the plaster. It's easy to drown it out.

For example, place a plaster template, bottom up, on a sheet of iron, and place it on an open fire. But this does not guarantee the “cleanliness” of the insides of the form.

If the part is not just a metal plate or something similar, but has protrusions, cutouts, and so on, then a different method is used.

An unnecessary metal container is taken, into which a plaster template is placed and water is poured. The dish is placed on the fire, and when the liquid boils, the paraffin will begin to collect at the top (float). But it’s unlikely that you’ll be able to wash the container afterwards.

After the melting process is completed, the gypsum is dried. The temperature should be low, otherwise the material may “burn out” and become deformed, especially thin parts of the template.

Pouring aluminum

There is nothing complicated about this, just one nuance. It is necessary to keep a stainless steel spoon ready, which will immediately remove the resulting oxide film.

A few notes

The “aquarium” shape can be made from any available materials. The main thing is that it does not fall apart during plaster pouring, and that it can be easily disassembled later.
It is not necessary to look for a muffle furnace or install a crucible as a heat source. You need to try whether the prepared aluminum scrap will melt, for example, from a gas burner. Perhaps argon welding will be sufficient. Everything that is on the farm is sampled.

When casting yourself, it is necessary to experiment, since the essence of all operations is presented quite clearly, and the examples given on equipment and materials are not dogma.

In Dahl's dictionary

and. chalk limestone; calcareous loam; white grayish clay, for coating cracks in a hut, esp. marl, clay for casting cast iron, copper arch.-mes. alabaster. | A soft and loose substance in general, fluff. | Frost on the trees, shaggy frost, kukhta, kurzha, kurzhevina, tver. Even. Dense opoka (on trees), for an oat harvest. Clean, loose soil, white, calcareous loam. Opoka kalyp, opoka lyak, mold for casting. Opoka sits on trees when it lets go, after severe frosts: the dampness of the air freezes on the frozen tree, boils, takes care of it; viscous clay, flask, sticks to the opener and spade, sticks or bakes. Opochnik m. opokovy, opochka stone, marl, tuff.

Silver casting

The noble metal silver is one of the oldest metals mastered by mankind. Being in nature in its native form, as well as its low melting point - 962 °C, gave our distant ancestors the opportunity to use this metal in the 4th - 3rd millennium BC.

Silver

Silver is a soft, ductile metal, excellent for the production of jewelry, ritual objects, mirrors and for minting coins.

Silver has the best electrical conductivity among metals and is used in the most critical electrical appliances and components. Excellent thermal conductivity makes it possible to use it in heating engineering.

Thermal conductivity of silver

Noble metal was widely used in photography in the 19th and 20th centuries.

Bactericidal properties of silver

Another important property has long been noticed - bactericidal properties. Silver vessels and filters are used to disinfect water. In Christianity and some other religions, the so-called is prepared in silver vessels. “holy water”, which helps with appropriate prayer against all ailments.

Silver casting technology

Silver casting in a factory environment is carried out using industrial technologies that require expensive equipment, significant energy consumption and the use of rare and dangerous components. Traditional technologies, proven over thousands of years, are more suitable for casting silver at home or in a workshop.

The most common of these is lost wax casting. The use of special modeling wax as a model material is also popular. The material used to create the mold is gypsum or clay-sand mixtures.

Silver ingots for casting

Silver for casting can be purchased at a savings bank or jewelry store in the form of ingots. In this case, its composition is precisely known and is stamped as a sample. If you decide to use grandma's spoons or scrap silverware, be prepared for the fact that you will have to carry out an operation to clean the scrap from impurities.

For example, silver is purified from impurities of base metals such as lead, copper and others by melting it in a crucible with the addition of saltpeter, borax and soda. Nitrate binds base metals, oxidizing them. Soda and borax transfer these oxides into solution, forming liquid slag.

The silver remains at the bottom of the crucible in the form of an ingot.

Lost wax casting. This silver casting technology is most accessible for beginners to master. The model is made of a material whose melting point is lower than that of the melt being poured. A mold of plaster or sand-clay mixture is poured or molded around the model.

Lost wax casting

The most common materials for lost wax models are wax and paraffin.

When the melt is poured into the mold, the model material melts and is forced out of the mold through a specially provided hole. The place of the model is gradually taken by silver.

There is a variation of this method in which the wax model is burned out by heating the mold to a high temperature, and casting silver is poured into the now empty mold.

To cast precious metal products at home you will need

Crucible for melting or cleaning metal.
Muffle furnace or gas burner.
Steel tongs.
Fireproof stand.
Scales
Modeling wax. Candle wax will not work.
Molding sands
Container for diluting the mixture
Scalpel, knives and files for processing the model and for finishing the finished product.
Casting mold
Hammer for breaking the flask.
Protective gloves, glasses and apron.
Fire extinguisher.
Dremel (mini drill)
Vices, Crossbars and Mandrels

It’s worth going into a little more detail on making a mold for casting silver. First, a model of the future product is created from wax by sculpting and cutting out small parts with a scalpel, completely repeating its shape, but having a thin protrusion in the form of a round rod.

Wax model for silver casting

This is the sprue that will carry the molten metal into the mold. Next, the model is placed in the flask and the molding mixture is poured.

If dry molding mixture is used, then the vibration compaction method is used for molding. Next, the model wax is burned out, and the mold is ready for pouring the melt.

Model casting in earth molds

Casting in so-called earth molds is the oldest method, proven over thousands of years.

Molding mixtures do not actually consist of black soil, but are a mixture of fine-grained quartz sand and plastic clay in certain proportions.

For casting small products with thin relief and a large number of parts, mixtures containing 12-15% clay are used, for large castings - up to 25%. Gases generated during casting must escape freely through the walls of the mold.

Casting silver according to models in earthen molds

The model for casting into earthen molds is made absolutely exactly repeating the original, but a little larger in size. This is an allowance for shrinkage and subsequent processing of the product. Models were traditionally made from wood, wax and plaster. Today, plastic models are becoming increasingly popular. The plastic holds its shape well and is easy to process.

Lost wax casting technology

Lost wax silver casting equipment is relatively uncomplicated and available for home use.

The essence of the method is that a model made of a low-melting material, upon contact with the liquid metal being poured, melts and is forced out of the mold through specially provided holes.

The metal occupies the void formed in the place of the model and accurately repeats its spatial shape.

It is necessary to pour the metal in a thin stream to allow the material of the lost wax model to leave the mold, in order to avoid the formation of splashes of molten metal.

Silver casting at home

Important! Casting silver with your own hands is a complex and fire-hazardous process. Your workshop should have fireproof stands and fire extinguishers designed to extinguish live electrical equipment. Be sure to wear fire-resistant gloves, an apron and goggles.

For casting silver at home, beginning craftsmen usually choose the following technologies:

wax modeling
earth casting
heating the crucible with a gas burner.

Of course, if you have a muffle furnace with adjustment and maintenance of a given temperature, a vibrating table and a centrifuge, your castings will only get better.

Casting silver at home is a complex process, but quite feasible with proper preparation and perseverance. Good luck in mastering this branch of metallurgy!

Mold casting: manufacturing, sand, shell molds

According to historians, the bronze casting is 12 thousand years old. Initially, using this technology, jewelry and simple tools were made from bronze. Over time, this technology has been improved, and today it is a method by which many unique products are created from this alloy.

The current level of development of bronze casting makes it possible to produce various objects from this copper alloy not only in production, but also at home.

Thanks to the invention of bronze, as well as the development of its processing technologies, the main of which is casting, we can still enjoy the sight of works of art that were created by masters back in the Middle Ages and ancient times.

Antique bronze set of writing instruments

Bronze casting, as well as brass casting, another alloy based on copper, gained the greatest popularity in the era of classicism and European Baroque. It was in those days that people learned to use these materials to create unique interior elements and decor.

Such alloys created on the basis of copper are still actively used in the manufacture of:

items used for interior decoration;
gates and fences that perform not only a decorative, but also a protective function;
sculptural compositions and souvenirs;
bas-reliefs and design elements of lighting fixtures - chandeliers and sconces;
elements of staircase structures and entrance groups.

Bronze casting for making knife handles

Many of these products, which are not large in size or complex in shape, can be made from bronze and brass not only in production, but also at home.

Stages of artistic bronze casting

In order to perform high-quality casting from a metal such as bronze, it is necessary to adhere to a certain sequence of actions. First of all, you should reflect in the sketch the shape of the product that you plan to cast from bronze.

Based on the sketch, which is created by professional artists and designers at modern enterprises, specialists create a drawing that accurately reflects all the dimensions of the future casting.

It is the drawing that is the basis for making an accurate model, which is used to produce a casting mold.

To create a model of a product that will subsequently be made from bronze by casting, various materials can be used, in particular:

Ivory;
wood (in this case, preference is given to such varieties of this material as pine, alder, beech, linden);
gypsum;
various types of polymer materials.

The cavities of the wax model of the future figurine are filled with clay, which will be removed after casting

To make the surface of the model as smooth as possible, it is primed, puttied and covered with several layers of varnish. When making a casting model, not only different materials can be used, but also different design approaches. So, models can be:

detachable (these are complex structures consisting of several component elements that can be connected to each other along flat or complex surfaces);
one-piece (monolithic models, the simplest type, most often used for casting at home);
special (this includes skeletal or molding templates used in cases where it is necessary to make a casting mold for the manufacture of objects with a complex configuration).

The next step after creating an accurate model of the future bronze product is the production of a casting mold. For this purpose, special devices and equipment are used, and the main materials used in this case are molding mixtures created on the basis of clay and carefully cleaned quartz sand.

The longest stage of bronze casting is molding - making a casting mold

In such a technological process as casting, made from bronze and any other metal, the casting mold plays a decisive role.

It is into such a mold, the internal cavity of which must exactly repeat the product being cast, that the molten metal is poured, and in it it cools, forming the finished casting.

Foundry molds, used both in production and at home, can be single-use or reusable, which is determined not only by the material from which they are made, but also by the features of their design.

Microcasting at home

A lot of cast parts made of non-ferrous metals and their alloys are used in technology, including quite complex and miniature ones, the serial production of which can only be afforded by enterprises with precision technology.

However, single (or even small-scale) microcasting can be organized at home.

It turns out that modern technology can be rivaled by the ancient method of injection molding using a simple manual centrifuge.

Almost everything that is needed for such micro-casting can be made by hand. Costs are minimal.

Indeed, the flask required for casting in this case is a piece of ordinary steel pipe with a diameter of 50-60 mm and a wall thickness of 2-3 mm. For casting products of different sizes, it is good to have several flasks of different diameters, provided that each one fits freely in the centrifuge bucket. If you have such a set, you can cast a whole series of parts one by one.

A centrifuge matches the flask in simplicity. Its wooden handle has a length of about 200 mm and a diameter of 20-30 mm. An M8 bolt is inserted into the axial hole of the handle. A metal earring is attached to it using a locked nut so that both the handle and the earring rotate easily without interfering with each other.

A bucket for a flask is suspended from the earring on a rocker arm made of 6 mm steel wire. The side of the bucket is made of a 60 mm piece of 80x3 mm steel pipe, and the welded bottom is made of a steel sheet 3 mm thick. The 200 mm high bow is made of the same 6 mm steel wire.

In order to confidently use such a centrifuge, you must first practice a little, remembering how in your school years in the physics room you had to twist a bucket of water on a string while studying centrifugal force.

True, now, instead of string and a bucket of water, in my hands I have a homemade centrifuge with a bucket, on the bottom of which there is a plastic cup (to prevent it from breaking).

But the water in it is ordinary, like it was in school physics experiments. And the action of centrifugal force is similar.

Holding the handle firmly, you need to rotate the entire chain (earring - rocker - bucket and vessel with water) around the bolt-axis, trying not to spill a drop.

Technology for producing high-quality micro-injection molding of non-ferrous metals and alloys using a manual centrifuge:

1 — bolt-axle; 2 - wooden handle; 3 — metal, easily rotating earring; 4 — locked nut; 5 — steel wire rocker; 6— bow; 7 — side of the bucket; 8 — bottom of the bucket; 9 — flask; 10 - molding compound; 11 — wax model; 12 — wax ball with technological wire pins; 13—casting mold with sprue channels, formed after melting the wax and removing the pins; 14—molten metal (alloy); 15 — flame of a gasoline burner; filling the mold with the melt while rotating the centrifuge and subsequent operations for removing and finishing the finished product are not shown

Once you get the hang of it, you can subsequently deal not with water, but with molten non-ferrous metal (or alloy), which will be pressed by centrifugal force through the gating channels into the casting cavity in the flask installed in a bucket instead of a plastic cup.

Perhaps the most difficult and time-consuming thing in micro-casting is the production of a three-dimensional, life-size wax model.

This one is molded from wax by hand, using a heated eye scalpel or a hot darning needle. Even small details are worked out with the utmost care, because molten metal (as well as any alloy) does not forgive mistakes and sloppiness. Moreover, casting, performed in a centrifuge under pressure, reveals all the flaws of the model!

In my practice, I use wax models whose height is no more than 40 mm and diameter is 50 mm. At the same time, I try to maintain proportionality so that the mass of metal in the casting does not exceed 40 g. The limitations are mainly due to the low power of the burner I use for melting.

Subtleties of technology

In order to perform artistic bronze casting or make a practical product from this alloy, it is necessary first of all to obtain molten metal.

Various types of furnaces are used for metal melting: induction, arc, flame, etc.

In the simplest version (when casting at home), you can use a regular gas burner to melt bronze, placing it under a special container for the melt.

The capabilities of small furnaces, which you can make yourself, are quite enough to melt non-ferrous metals and their alloys, which also include brass and bronze.

To melt a small amount of bronze you need a fire brick and a gas burner

The most important step in bronze casting is filling the mold with molten metal. Despite the fact that such pouring lasts only 1–2 minutes, the correctness of its execution directly affects the quality characteristics of the finished product. The result of incorrect filling can be such defects as:

These bronze castings developed cavities due to poor cleaning of the crucibles before pouring.

When casting small-sized brass and bronze products, the molten metal is poured not from the crucible itself in which it was heated, but using a special device used as a hand ladle or spoon.

The metal, which has already been poured into the mold, must be allowed to cool to the required temperature, which, depending on the brand of alloy used, may vary.

The procedure for removing the finished product from the mold depends on what type it is - disposable or reusable. In the first case, it is simply broken with a hammer, and the casting is removed using pliers.

Reusable molds, accordingly, do not need to be broken: they are simply opened along the surface to be joined and the casting is carefully removed from them.

The newly removed casting needs to be reworked. This modification consists in the fact that the sprues, spurs, profits and bays formed during the casting process are removed from the surface of the product. This operation, which can be performed using various mechanical tools, is called trimming.

Jewelry casting at home for beginners

But how are we going to fuse paraffin onto a ring when it is incredibly fluid and unpredictable? It turned out that everything is much simpler. In the process, the master realized that paraffin remains plastic for a long time and can be deformed like plasticine. And so it happened. He simply molded the desired ring shape and continued.

True, it wouldn’t hurt to go through a soldering iron in order to fuse the molded boundaries. But the master decided not to do this. Later on the castings this will appear as a defect, but not so bad that you can’t wear this ring. Now we need to process the molded model.

The master decided to do it with sandpaper, but he doesn’t remember whether it was forty or sixty, but it was definitely very rough. And again for good reason. The fact is that a large grain of sandpaper leaves a deep mark on the paraffin and gives it texture.

Therefore, carefully walking along the front part of the ring with coarse sandpaper, we will leave the resulting texture for casting. Since the paraffin could fail at any moment, the master decided to leave the finishing work to the brass casting.

How to cast an aluminum part at home

For many, the term “foundry” is closely associated with back-breaking labor and specialized professional skills.
In fact, casting a part from the required metal is possible for the most ordinary person without professional training at home. The process has its own subtleties, but it can be done at home with your own hands.

Outwardly it resembles the production of lead weights for fishing. Features of the aluminum casting process are related to the technical characteristics of the material.

How to cast aluminum

Characteristics of aluminum.

Aluminum is one of the most common metals.

It is silver-white in color and lends itself quite well to casting and machining. Due to its characteristics, aluminum is equipped with high thermal and electrical conductivity, and also has corrosion resistance.

Technical aluminum has a melting point of 658 degrees, high-purity aluminum has a melting point of 660, and the boiling point of aluminum is 2500 degrees.

For aluminum casting, home heating devices are unlikely to be useful and will provide the required temperature. It is necessary to melt aluminum by heating it to a temperature of over 660 degrees.

Aluminum casting: choosing a heat source

The following can be used as a heat source for aluminum melting:

A very effective method is achieved using a self-made crucible muffle furnace. A crucible (a necessary tool for melting aluminum) is installed on the working surface of this furnace, and raw materials are added to it. Using a muffle furnace you can cast aluminum very easily.
Do-it-yourself muffle furnace for melting aluminum, here!
To obtain the melting temperature of aluminum, the combustion temperature of liquefied or natural gas is sufficient; in this case, the process can be performed in a homemade furnace.
With a small volume of melting, you can use the heat obtained by burning gas in a household gas stove.
The required temperature will be provided by gas cutters or acetylene generators, if available in the household.

Aluminum preparation

Despite the fact that the melting process will be performed at home, it must be handled responsibly. The metal must first be cleaned of dirt and crushed into small pieces. In this case, the melting process will go faster.

The choice is made on softer aluminum, as a purer material with fewer impurities. During melting, slag is removed from the liquid surface of the metal.

Sand casting

Several technologies are used to produce casting parts. The simplest is sand casting:

If you need to make an aluminum part of a simple shape, then open casting can be done directly into the soil - silica. A small model is made from any material: wood, foam. Install in the flask. The soil is laid around in small layers and compacted thoroughly. Once the sample is removed, the silica holds its shape well and the casting is done directly into it.

As a forming mixture, you can use sand combined with silicate glue, or cement mixed with brake fluid. The ratio of materials should be such that if the mixture is compressed, it retains its shape.

“Casting aluminum into an earthen (sand) mold at home”

For parts with complex shapes, a different technology is used.

Lost wax casting

This long-known method for making aluminum products at home can be slightly modified. The casting principle is as follows:

The model is made from low-melting material. It is placed in a certain shape and filled with plaster. One sprue or several are installed. After the plaster has hardened, it is dried well. At high temperatures, the low-melting material turns into a liquid state and flows out through the sprue. An aluminum billet is poured into the resulting mold.

The recommended material is wax, but it has one very big drawback. This is a high price for the material. But for small parts it will not cause much harm to the family budget.

Details of the process can be clarified in the video.

"High Pressure Aluminum Casting"

Thus, even the most ordinary amateur craftsman can make the necessary part from aluminum of various shapes.

How to cast a complex-shaped part from aluminum

Industrial enterprises often use metal molds. Aluminum casting molds can be made from a variety of materials. Most often, gypsum is used. Gypsum can be purchased at any hardware store at any price acceptable to you. It is recommended to use sculptured or white plaster.

An excellent option is sculptural, which is marked G-16. Due to the high price, it can be replaced with G-7 - ordinary white plaster. It is strictly forbidden to replace it with alabaster, despite the fact that they are often interchangeable in construction work.

Let's look at a simple way to cast an aluminum part with your own hands at home.

To cast an aluminum part we need:

melting vessel;
scrap metal;
melting mold.

Main stages of the process:

1. Prepare a vessel for melting (you can use a vessel from part of a steel pipe).

2. We make a mold for melting. If the part has a complex structure, then the shape may have several components.

In our version, the form will consist of two parts. First, think about how to simplify the part for convenience (we recommend strengthening the holes with tape).

The mold is very easy to make from sculpting plaster (do not use alabaster!). You can use plasticine.

3. Before pouring plaster, you should lubricate the container with oil so that the plaster cannot stick to the container.

4. Carefully pour the plaster, shaking the mold periodically to release the bubbles.

It is important to know:

The hardening process of plaster is quite fast, so be careful and try to install the model in plaster in time.

In addition, it is recommended to install an object (for example, a small stick) in the plaster, which will become a channel for pouring our part.

5. A primary layer is required for the upcoming filling.

Take a drill and make 4 small holes, treat the shape with oil. This is necessary to ensure that the finished mold parts lie as stable as possible during the casting process.

6. Fill the second layer.

7. After hardening occurs, you need to carefully remove the mold from the container and separate the halves.

8. Before casting, we treat the mold with soot to avoid sticking of liquid aluminum. The form must be dried. The natural drying process takes place all day long.

It is advisable to dry the gypsum blank in the oven. Start at a temperature of 1100C - one hour and two hours at a temperature of 3000C.

It is necessary to provide holes in the plaster for pouring aluminum and removing residual air.

This is how we melt aluminum.

9. Then we place the liquid metal in the mold and wait for it to cool completely.

As a result, we obtain the desired workpiece, then we grind it and make special holes.

Burnout casting: technology features

Manufacturing a part from aluminum using burn-out casting has its own characteristics, which will be discussed below. The work is performed in the following sequence:

Foam plastic is used as a material for the model at home. Using cutting elements and glue, make a figure that resembles the required shape in outline.

Prepare a container for making the model. You can use an old shoe box. Mix alabaster with water. Pour the mixture into the box. Place the foam model. Level it out. Give the material time to harden well. Due to the rapid hardening process of alabaster, perform the work at an accelerated pace.

Remove the box. Heat the mold in the oven to dry the alabaster and remove any remaining moisture. Otherwise, all the water from the alabaster will enter the aluminum and turn into steam, which will lead to pores in the metal and aluminum splashing out of the mold during work.
Melt the aluminum. Remove molten slag from the liquid surface. Pour the metal into the mold in place of the foam. Due to the high temperature, the latter will begin to burn out and aluminum will take its place.

After the metal has cooled, break the mold and remove the resulting cast aluminum model. You can watch the process in more detail in the video.

Safety precautions and workplace preparation

High-temperature work is characterized by harmful fumes and is accompanied by the release of smoke, so they must be performed in the open air or in a forced-ventilated area. A side-flow fan must be used.

The casting process is accompanied by splashes and flows of molten metal are possible. The workplace will need to be pre-covered with a sheet of metal. It is not recommended to carry out work in a residential area - it is unsafe for others.

Basic mistakes when casting aluminum

Before casting aluminum at home, pay attention to the main errors that are observed when performing work:

When making plaster molds, it is necessary that all moisture evaporate during the drying process. Otherwise, when filling the mold, the water begins to evaporate, turns into steam and may remain inside the aluminum in the form of pores and shells.
If the heating is insufficient or if the aluminum has time to cool before starting work, the metal will not fill the mold well and distant areas will remain hollow.
Do not cool metal by immersion in liquid. In this case, the internal structure of the material is disrupted.

Interesting facts about aluminum

Aluminum can bend like paper or be as hard as steel. Aluminum is everywhere, even inside us.

Every adult gets about 50 mg of aluminum every day through food, this is not some kind of diet, it just cannot be avoided.

Aluminum is the most common metal on the planet. Its content in the earth's crust is 8%, but it is not easy to extract, at least in its pure form.

Unlike gold and silver, aluminum is not found in nuggets or whole veins. Aluminum is 3 times lighter than iron or copper.

Aluminum in its original form does not look like metal at all, this is all because of aluminum’s special “love” for oxygen.

In fact, the first use of aluminum in history occurred when Eastern potters added aluminum-rich clay to their wares to make them stronger..

Sufficient for the production of beer cans, strong for racing cars, flexible for the skin of airplanes, capable of being turned into anything, aluminum is an indispensable material for the modern world.

And these are not all the features that this useful metal stores.

Selected for you:

Do-it-yourself casting box

Silver

Silver is a soft, ductile metal, excellent for the production of jewelry, ritual objects, mirrors and for minting coins.

Thermal conductivity of silver

Noble metal was widely used in photography in the 19th and 20th centuries.

Bactericidal properties of silver

Do-it-yourself molding sand for casting – vending-doctor.ru

Mankind knows many metals and alloys based on them. One of the most famous is brass. This is a copper-based compound to which third-party non-ferrous metals are added.

Various parts and elements for electrical equipment are made from this material. Casting brass allows you to make workpieces of various shapes and sizes from it.

It can be carried out at the enterprise or at home.

Brass casting

Characteristics and applications of brass

Brass is an alloy whose main components are copper and zinc. The traditional compound is a mixture of 70% of the first metal, 30% of the second. However, there are materials where the zinc content reaches 50%.

To understand how to work correctly with this connection, you need to understand its characteristics:

Melting point - up to 950 degrees.
Density - about 8.7 tons per m3.
Electrical resistance - 0.08 microns per meter.
Heat capacity - 0.377 kJ/(kg K)

Brass products can be a mixture of copper and zinc, or these two components and additional alloying additives. The alloy is used in various industries:

production of components for watches;
creation of figurines, jewelry, interior elements;
production of parts used in mechanical engineering;
creation of components for electrical equipment.

Brass has good weldability. In addition, it has a high corrosion protection rate. Due to these characteristics, the alloy is used as a protective coating for other metals in the manufacture of metal structures.

History of technology

Historians say that brass appeared simultaneously with bronze. Alloys were used to make jewelry, tips for tools, weapons, dishes, and cutlery.

To make any item, you had to know the technology of brass casting. Over time, the method developed and improved. Today, the material can be made at home or in production. To do this, you need to accurately carry out the technological process, follow the rules, choose the right tools and raw materials.

Product made of brass

Disposable flasks

Having learned what a flask is and how it is used, it is easier to understand the intricacies of the process. It no longer seems so complicated, but rather interesting and simple. Modern technologies allow you to try to make your own jewelry almost at home.

The Chinese market offers a wide range of disposable molds with ready-made molds. All that is needed to work with such a form is the required amount of precious metal and the ability to melt it.

They are used both by jewelers who do not have their own foundry, and by freelance craftsmen who make custom-made jewelry.

Anastasia Razulite

What is required for casting?

To melt brass, you must initially prepare equipment and tools for the work. This includes:

Molding compositions. Made from fireproof materials. The shape is selected depending on the required finished product.
Special tongs used to make it are removed from the molds after hardening.
Heating equipment. You can use a purchased model or make a stove yourself. For assembly you will need fireclay bricks and fireproof mastic. For heating, you can use a gas burner or nichrome wire.
A crucible is a container that is filled with consumables. They melt when heated. Then the master pours the molten metals into a mold prepared in advance. The crucible is made of clay or graphite. Additionally, heat-resistant coating is used, which increases the durability of the container.

In order to remove the crucible from the furnace, semicircular tongs are used.

Opok deposits

Volskie opok deposit

Volsky deposits of cement raw materials in the Saratov region. The Volsk deposits of chalk, clay and opoka with total proven reserves of 445, 91 and 73 million tons, respectively, are located in the Middle Volga region near the city of Volsk and are developed in five quarries. The geological structure of the deposit area involves horizontally occurring sedimentary marine deposits of the Lower and Upper Cretaceous, Paleogene (Syzran stage) and Quaternary. At the base of the section there are gray sandy clays of the Aptian stage (6.1–22.4 m), overlain by a layer of opoka-like sandstone (0.9–4.0 m); higher up lie black fatty clays of the Albian stage (7.7–17.5 m). Upper Cretaceous deposits begin with marly chalk of the Turonian stage (4-12 m) with a layer of inoceramic marl at the base (1.5-4.0 m); further up the section follow Turonian marly chalk (4–12 m), Coniacian-Santonian breccia chalk (2.5–4.0 m), Campanian, so-called intermediate chalk (12–19 m) and Maastrichtian white soft chalk ( up to 60 m). On the eroded surface of the Maastrichtian chalk lie the Lower and Upper Syzran dark gray and black clay opokas (1.6–56.0 m), overlain by Quaternary loams (up to 10.6 m) with a soil-vegetative layer. Most of this section is productive: the Lower Cretaceous, including a layer of opoka-like sandstone, for clayey raw materials, the Upper Cretaceous (without a layer of inoceramic marl at the base) for carbonate raw materials, and the Paleogene for high-siliceous raw materials. Raw materials extracted from quarries are processed at cement plants according to the classical scheme.