Master class on making a master model from casting wax. Part two. Casting

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.

Casting steel at home

Elegant replicas of ancient warriors, miniature works of art, bizarre animals and much more are reflected in metal figurines that can be bought at any gift shop. But what if you want to surprise your friend with an exclusive item? This article describes a method for casting metal at home.

Before you start creating this or that fancy shape, you must think through a clear sequence of your actions. Remember the main thing: since you are working with molten metal and possibly open flame, follow all fire safety rules.

You will need wax (preferably modeling wax), primitive tools (use whatever seems right for you) to give the wax the shape of your figurine. Gypsum, dishwashing liquid (applying a release layer) to create a reusable mold. You also need material to create a flask - a container that holds the molding sand as it is compacted. Figure No. 1, 2.

Figure No. 1 - Molding

Figure No. 2 – Figurine placed in a flask

On the Internet you can find many recommendations on this topic. Please pay attention to the following nuances:

1) If you want to make several figurines, you need a reusable collapsible form. When creating a collapsible form, you will need to provide guides - I have highlighted them in red in the pictures. You need them to ensure that the form always aligns correctly when closing it.

Figure No. 3 - The lower half of the collapsible mold with an installed guide

1- Wax model figurine

The guides must be provided with rhinestones; I recommend filling the lower half of the collapsible mold with plaster, after drying, carefully drill holes and insert wooden rods into them. Then apply a separating layer and fill the second part of the mold, leaving holes for metal and air.

Figure No. 4 – Sectional view of a reusable collapsible form

3 - Sprue for metal;

4 — Hole for air outlet (it is not necessary to make it from the top).

2) Before pouring the metal into the finished mold, it must be well heated to the temperature of the metal.

3) Melt a little more metal than the volume of your figurine - this is necessary so that it fills all the voids in the form. You also need to create pressure using some kind of plug, plugging it into the hole into which the metal was poured, drawing No. 5.

Figure No. 5 - Illustration of the process of pouring metal into a mold

5 - metal is poured through a wide funnel;

6 - air exits through a special hole.

The cork is highlighted in orange, the guides are in red, and the molten metal is in blue.

PS: I tried to clearly show and describe non-tricky tips. I hope that at least something is useful to you. But this is not everything that can be imagined, so go ahead and study the site https://bip-mip.com/

1. Reusable plaster moldIf you need to make several identical plaster figurines.
2. Electric spark pencil You can engrave on metal with a variety of devices, from pens and...
3. Homemade case When you assemble this or that device, it is not enough to purchase it.
4. Powder for cleaning metals We all know about the benefits of chemicals in everyday life.
5. Do-it-yourself thermal jigsaw For figured cutting in low-melting sheet materials, it is convenient to use this way.

For a long time, men began to think about how to create their own furnace for melting metal at home. It must be portable and meet all conditions. The production facility has furnaces for melting large quantities of metal. At home, you can assemble a furnace for melting up to five kilograms of aluminum. Let's look at how to make a smelter at home.

Equipment and materials you will need

In order to melt metal, you need to buy the following components for manufacturing:

• fire brick;
• nails;
• transformer;
• copper wire;
• graphite;
• mica;
• asbestos and cement tiles;
• gas-burner;
• crucible.

The dimensions will vary depending on the wishes of the person collecting it. It is better to create a small furnace for melting metals if you want to use it only for your needs. You will spend less time making it, and a small amount of kilowatts will be spent heating it. If you do it using diesel fuel or coal, then do not forget about installing thermal insulation and air supply.

Metals such as iron, nickel, tin, and copper are melted in an electric furnace. The output voltage in an electric furnace should be greater, which means the distance between the electrodes will increase. Brushes from an electric motor are suitable instead of electrodes.

Step-by-step instruction

How to make a melting furnace at home - read the following instructions:

• A high-frequency alternating current generator is installed.
• Spiral winding. Made from copper wire.
• Crucible.

All these elements are placed in one housing. The melting cup is placed in the inductor. The winding is connected to the power source. When the current is turned on, an electromagnetic field appears. The resulting eddy currents pass through the metal in the cup and heat it. Melting occurs.

Homemade muffle furnace

The positive properties of an induction furnace are that when melting metals, a homogeneous melt is obtained, alloying components do not evaporate, and melting occurs quite quickly. In addition, the installation of such a stove does not harm the ecosystem and is safe for the user.

Foundry models

Artistic casting of bronze and brass involves obtaining the smoothest possible surface, so fairly hard materials are used to recreate the model:

1. wood;
2. gypsum;
3. Ivory.

To obtain the smoothest possible surface, it is subjected to elimination of porosity by puttying, priming and varnishing. Casting models are made split; one-piece - suitable for casting products of simple shapes; special for parts with a rather complex configuration.

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.

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 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.

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

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.

Metal casting at home

Metal casting is a popular technological process that allows you to produce metal products of the desired shape. Casting is carried out from various alloys that have varying degrees of fluidity in the molten state.

This method of execution allows us to produce high-quality products without the use of bulky equipment and a huge number of workers. In the modern market, this technology is in great demand, and is also among the ten most effective and used in the world.

A little history

The most important feature of iron, when it solidifies, to take the form “proposed” to it, was noticed by man back in ancient times.

Today, almost all scientists assume that man’s initial acquaintance with metal took place thanks to meteorites.

Meteoric iron was fusible and easy to process, so some nascent civilizations had been studying the basics of casting for a very long time.

In our country, metal casting has been a respected and honorable business from time immemorial; people have always treated this craft with great respect. The “Tsar Cannon” and “Tsar Bell” are widely known, being masterpieces of Russian foundry craftsmanship, even if one of them never rang and the other never fired.

During the reign of Peter the Great, the Ural foundry workers gained particular fame as suppliers of reliable weapons for the army. However, they rightfully bear this title even now. Before we look at the main types of metal casting, it is necessary to say a few words about the required characteristics of the raw materials.

What type of metal should be used for casting?

The most important property of the metal that is supposed to be used for casting is its fluidity. The alloy in molten form should flow as easily as possible from one crucible to another, while filling its smallest recesses.

The higher the fluidity, the thinner the walls can be made of the finished product. It’s much more difficult with metal that doesn’t flow well. Under normal conditions, it manages to set much earlier than it fills all the gaps in the form.

It is this complexity that industrialists face when casting metal alloys.

It is not surprising that cast iron became the favorite material of foundries. This is because this alloy has excellent fluidity, making it relatively easy to work with. Steel is far from being so fluid, and therefore to completely fill the mold (so that there are no cavities and voids) you have to resort to a variety of tricks.

In the simplest case, when home-made metal casting is required, the raw materials are melted and poured into water in small portions: this way, in particular, fishing sinkers can be made.

But this method is relatively widely used even in the weapons industry! From the top of a special tower, whose outline resembles a cooling tower, molten metal also begins to pour out in measured doses.

The height of the structure is such that a perfectly formed droplet, already cooled, reaches the ground. This is how shot is produced in industrial quantities.

"Earth" casting method

The simplest and most ancient method is to cast metal into the ground. But its “simplicity” is a relatively relative concept, since this work requires extremely painstaking preparation. What does it mean?

First, a full-size and maximally detailed model of the future casting is made in the model shop. Moreover, its size should be slightly larger than the product that should be obtained, since the metal will settle during cooling. As a rule, the model is made detachable, from two halves.

Once this is completed, a special molding mixture is prepared. If the future product must have internal cavities and voids, then you will also have to prepare rods, as well as additional molding composition.

They must temporarily fill those areas that are “empty” in the finished part.

If you are interested in casting metals at home, be sure to remember this circumstance, since otherwise the already filled flask may simply be torn apart by pressure, and the consequences of this may be the most tragic.

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:

1. Melting point - up to 950 degrees.
2. Density - about 8.7 tons per m3.
3. Electrical resistance - 0.08 microns per meter.
4. 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.

What are molding sands made from?

The basis is various types of sands and clays, as well as binding compositions. Their role can be natural and synthetic oils, drying oil, resin, rosin, and even tar.

Next comes the time of molders, whose task is to make casting molds. To explain it more simply, this is done like this: take a wooden box, put half of the mold in it (it’s also detachable), and the spaces between the walls of the model and the mold are clogged with molding compound.

They do the same with the second half and fasten both parts with pins. It is important to note that two special cones are inserted into the part of the mold that will be at the top when pouring. One of them is used to pour in molten metal, the second is used to release expanding gases.

Chemical processes during hardening of gypsum mixtures

Hardening of
the gypsum-water
system After mixing the gypsum mixture (its basis is anhydrous calcium sulfate, semi-aqueous gypsum and semi-anhydride) with water, solid hydrated calcium sulfate is formed in accordance with the equation

Copper casting

Copper is one of the first metals mastered by mankind.

Copper

Thanks to its low melting point and high plasticity, it has not lost its popularity for the fifth millennium. Red metal is widely used both in industry and at home to make jewelry, crafts and parts by casting copper.

In industrial settings, technologies such as

Copper casting

• Casting copper into molds
• Powder metallurgy
• Electroplating
• Hot and cold rolled
• Sheet stamping
• Wire drawing
• Mechanical restoration

They require complex and expensive professional equipment, highly qualified personnel and are accompanied by high energy costs.

General characteristics of the metal

Bronze is an alloy that may contain tin, copper and other components. Foreign impurities include zinc, aluminum, beryllium, lead, nickel or silicon. If we talk about composition, bronze can be divided into two groups:

1. Tin alloys. The material may consist of two or several components. Tin is the second most abundant component of the alloy.
2. Tin-free alloys. The composition may include aluminum, lead, silicon, lead or beryllium. These components change the characteristics of the alloy.

The characteristics of the bronze alloy include:

1. Density. This indicator depends on the tin content in the composition. Average number 9.1 kg/cu.m. cm.
2. The temperature at which metal melts. Varies depending on the components of the composition. Range 880–1060 degrees Celsius.
3. Heat capacity - 0.385 kJ / (kg*K).
4. Electrical conductivity - 0.176 μOhm*m.

If you want to change any of the characteristics of the alloy, a certain amount of foreign impurities is added to its composition.

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

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:

1. Molding compositions. Made from fireproof materials. The shape is selected depending on the required finished product.
2. Special tongs used to make it are removed from the molds after hardening.
3. 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.
4. 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.

How to cast aluminum at home?

The technology for producing aluminum at home is almost identical to industrial methods. Therefore, at low tide, they require the use of factory methods with minor adjustments to the scale of production and home conditions. The most common technology for casting aluminum at home is the use of molds.

Aluminum casting molds

Considering all of the above, you need to select the necessary equipment (a furnace for scrap aluminum) and build a mold for casting (how to do this will be discussed later).

The process itself will consist of several stages:

• Cleaning scrap from dirt, impurities and various fillers that can affect the final purity of the alloy. At the same stage, it is necessary to grind the aluminum to a small size.
• The melting process is carried out using a pre-selected method. Complete melting of the metal allows you to remove all unnecessary additives from the metal mass. And also at this step the molding mixture is selected.
• The final step is to add the aluminum to the prepared melting mold. Next, you should wait until the mass hardens and after that you can release the alloy from the mold.

This will complete the casting process. Throughout the entire procedure, you should follow safety rules when working with hot metal.

Casting aluminum at home - step-by-step instructions

31.03.2015

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.