How to make a mini smelter for melting aluminum. Homemade electric furnace for melting metals. Details of how to make a furnace for melting.

A furnace for melting metals at home can also be used to quickly heat metal elements, for example, when tinning or forming them. The operating characteristics of the presented installations can be adjusted to a specific task by changing the parameters of the inductor and the output signal of the generating sets - this way you can achieve their maximum efficiency.

Aluminum alloys have low melting point and good workability details. And there is always a lot of aluminum scrap on the farm.

That's why aluminum is often melted at home to replace non-standard or small parts of mechanisms: a blank is cast, and then processed on a lathe. Sometimes souvenirs and small interior items are made from aluminum with their own hands.

Melting furnace structure

Homemade furnaces for melting aluminum consist of a body - metal cylinder (2), lined with refractory (clamotte with sand or concrete). Inside the mine is charcoal (8), serving as fuel. It is installed crucible (3)- a container in which the metal will melt. The crucible can be a thick tin can, a teapot or any stainless steel container.

At the bottom of the shaft (6) made air injection hole (7) through lattice base (4), which allows you to maintain combustion and regulate the temperature in the furnace.

A hair dryer or a vacuum cleaner pipe is used as a blower. Damper (5) necessary to remove excess air.

For ovens with a capacity of several tens of kilograms, you need cover (1) for quick and uniform heating of the metal. In small ovens you can do without it.

Furnace elements should not deform or melt when heated. Therefore, the use of aluminum bodies, tubes and crucibles is unacceptable. It is best to take steel or cast iron details.

Reference. Also used as fuel for smelting aluminum natural gas or electricity.

How to make a furnace for melting metal?

Creating a small unit that can melt several kilograms of aluminum scrap is not a difficult task. To lay out the stove in the garden you will need following materials:

• red bricks - 20-25 pcs.;
• high tin can - 1 pc.;
• grill grate - 1 pc.;
• drying hair dryer - 1 pc.;
• piece of pipe, with a diameter suitable for the outlet of the hair dryer - 1 PC.;
• roll of electrical tape;
• line segment steel wire length 30-50 cm;
• coal for ignition (the quantity depends on how much aluminum needs to be melted).

The bricks will appear simultaneously and body and fireproof coating oven, a tin can will act as a crucible. At the top of the can are being done two holes opposite each other, and through them the wire is threaded. It will be possible to lift and remove the crucible with the melt from the furnace. The air will be supplied from the hairdryer turned on in cold air mode. Tape or tape to the outlet of the hair dryer attach a piece of pipe- this will be the air duct.

Such simple circuit The furnace is convenient in that no tools are actually required to create it; everything is done by hand.

Important! Do not use oven elements with zinc coating, because when aluminum is melted, toxic zinc fumes will be released.

Brick well installation plan

1. Gives his all one row bricks in the form of a rectangular well. The internal dimensions of the hole should be approximately length and width of one brick. On one side two bricks laid out so as to form a corridor for the air duct. The width of the corridor is tube diameter for air supply.
2. On the laid out row grating is installed. Instead of a grill grate, you can use any metal lid or plate with holes for air supply.
3. Placed on the grill second row bricks, without any gap for the air duct.

Photo 1. Finished brick well for the melting furnace. The edges are reinforced with metal strips, the air duct opening is visible.

1. Created air duct. Tape or tape to the hairdryer a piece of pipe is wound. To ensure structural strength, the connection point wrapped in thick paper, and then connects duct tape. Electrical tape is a more elastic material compared to adhesive tape, so it is more convenient to work with. The cold air supply button is also secured with tape on the hairdryer. Ready the mechanism is brought to the bottom row bricks.
2. In the stove well on the grate coal is poured and melted for ignition. The hair dryer turns on, which activates the combustion process.

Advice. The air supply intensity can be adjusted by changing hair dryer operating mode, and distance between pipe and window for the air duct.

1. Tin is installed to the top row bricks for the wire threaded into it. Like a pot over a fire, it hangs over the grate.
2. After lighting the furnace and installing the crucible third row are placed two more bricks so that from a rectangular hole you get a square one. This will fix the can inside the housing and heat up the oven space faster.

After heating the jar into it scrap can be loaded for remelting. A sign that the jar is warming up is its redness.

The principle of the design and operation of such a furnace is very simple and does not cause difficulties. However, it is always worth remembering safety precautions:

• work in fire-resistant gloves;
• avoid water getting into the melt;
• do not use materials containing toxic substances.

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Two-can design

Another type of homemade furnace for melting aluminum is a design made of two large cans. One of them serves body, in which a hole is cut for air supply, and bottom of the second jars with holes serves as a divider.

A crucible is installed inside the jars.

Such a device very compact, and small volumes of metal can be melted even in a ventilated garage. However, the design is not resistant or fire resistant, and will only last a few cycles.

Possible problems and their solutions

Carelessly assembled device causes the oven to operate inefficiently and makes it dangerous to use. Here are a few points to pay attention to:

• Slots and gaps in a brick building. They can be caused by chips on bricks or loose fit of refractories to each other. Gaps reduce fuel efficiency and reduce combustion intensity and temperature. Aluminum in a crucible may simply not melt.

Therefore, after laying out each row, a visual check is carried out for the presence of holes. Holes covered with a sand-clay mixture or covered with fire-resistant material.

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It is recommended to use concrete mortar only in the case of a stationary unit that is not planned to be disassembled. But Asbestos sheets and chips should not be used in places where the stove is heated, because this material is a carcinogen.

• Violation of the horizontal level the buildings. Misalignment reduces the stability of the structure and creates conditions for uneven distribution of coal. The result is uneven heating of the crucible and the metal in it.

Laying out each, especially the bottom row of bricks controlled by level. You can also check horizontality placing a jar of water on the grill. On a flat surface, the top edge of the water will be parallel to the edge of the can.

The approximate melting point of aluminum is about 660 degrees Celsius, which makes it possible to melt it even at home. Of course, it will not be possible to reach such a temperature on a gas stove, and it is extremely undesirable to carry out such work indoors. There are many videos on the Internet on how to do it yourself. In this article we will look at the most interesting, proven and reliable methods.

Kinds

Ovens, used in industry, are very expensive. Their price is thousands and tens of thousands of dollars. In addition, such units take up an prohibitively large amount of space. Aluminum is the most common metal on Earth, so the industry has made great progress in this direction. There are many types. For example, inclined cylindrical furnaces, furnaces with reverberation crucibles, rotary furnaces and others.

But what should you do if you need to make a part at home, but for one reason or another there is no way to order it? Excellent mini oven absolutely easy to make and with your own hands, and for this, basically, you will not need to look for any specific materials, parts and devices. Most of them can be found in almost every home, garage or country house.

In essence, the operating principle of all homemade stoves is simple and the same. The differences, as a rule, are only in some of their design features. In some volumetric heat-resistant vessel are kindled charcoal(this is the most successful fuel option for aluminum smelting), into or over which The crucible contains the metal itself. The crucible can be, for example, cut off fire extinguisher body, or even ordinary steel kettle. To increase the temperature of the coals, high-quality airflow from all sides is necessary (so that the aluminum is heated evenly in the container). Typically, oxygen is supplied through a pipe down the “well”. Cravings An ordinary vacuum cleaner, a motor from an old hood, a cooler, or even a hair dryer can create one. In principle, these are the necessary conditions for creating a kind of mini smelter with your own hands.

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Plaster is usually used as a mold for casting parts. If you need to cast an ordinary cylindrical blank from aluminum, a piece of cut steel pipe will do. Let's look at the most interesting and simple designs of mini ovens.

Mini-oven made from a wheel rim

Making this model is very simple. Wheel rim of the desired diameter is dug into the ground so that its surface coincides with the horizon, that is, does not protrude above the surface of the earth. In the middle of the disk inside the resulting firebox there should be a hole through which we pass curved pipe, overlooking next to the smelter. Oxygen will flow through it into the mini-oven from below. Convenient to use as a blower small cooler, put on the pipe from the outside. However, with such an air supply, the blowing will be extremely poor quality and unidirectional. To do this, we will build something like a burner inside the boiler at the outlet of the pipe. Convenient to use for this car disc brake, welded on top of the pipe. After this, coals can be poured into the resulting mini-smelter and air can be supplied to raise their temperature. Aluminum scrap in a crucible is placed among coals.

Metal tank oven

It is not necessary for the stove to be sunk into the ground. Easy to make with your own hands and portable oven. Anyone can do this cylindrical tank made of heat-resistant metal, for example, a tub from an old top-loading washing machine. From the inside, the diameter of the tank is reduced due to bricks and clay. Thus, the thickness of our oven will be 10-15 centimeters. Don't forget to install an inflation pipe at the bottom of the housing. Air can be supplied into it in any convenient way. Crucible with aluminum raw materials hangs inside the firebox. As you can see, there are no fundamental differences from the previous version. It’s just as easy to make it yourself, the only differences are in the necessary tools and parts.

Nowadays, induction furnaces are widely used in the metal smelting process. The current produced in the field of the inductor contributes to the heating of the substance, and this feature of such devices is not only basic, but also the most important. Processing causes the substance to undergo several transformations. The first stage of transformation is the electromagnetic stage, followed by the electrical stage, and then the thermal stage. The temperature generated by the stove is used practically without any residue, so this solution is the best among all others. Many may be interested in a manufactured stove. Next we will talk about the possibilities of implementing such a solution.

Types of furnaces for melting metals

This type of equipment can be divided into main categories. The first has a heart channel as its base, and the metal is placed in such furnaces in a ring manner around the inductor. The second category does not have such an element. This type is called a crucible, and the metal is placed inside the inductor itself. It is technically impossible to use a closed core in this case.

Basic principles

The melting furnace in this case operates on the basis of the phenomenon of magnetic induction. And there are several components. The inductor is the most important component of this device. It is a coil, the conductors of which are not ordinary wires, but copper tubes. This requirement is imposed by the design of the melting furnaces itself. The current that passes through the inductor generates a magnetic field that affects the crucible inside which the metal is located. In this case, the material plays the role of a secondary transformer winding, that is, a current passes through it, heating it. This is how melting occurs, even if you make an induction furnace yourself. How to build this type of furnace and increase its efficiency? This is an important question that has an answer. The use of high-frequency currents can significantly increase the efficiency of equipment. For this, it is appropriate to use special power supplies.

Features of induction furnaces

This type of equipment has certain characteristic features that are both advantages and disadvantages.

Since the distribution of the metal must be uniform, the resulting material is characterized by a good homogeneous mass. This type of furnace works by transporting energy through zones, while also introducing the function of focusing energy. Parameters such as capacitance, operating frequency and lining method are available for use, as well as regulation of the temperature at which the metal melts, which significantly facilitates the work process. The existing technological potential of the furnace creates a high melting rate; the devices are environmentally friendly, completely safe for humans and ready for use at any time.

The most noticeable disadvantage of such equipment is the difficulty of cleaning it. Since the slag is heated solely due to the heat generated by the metal, this temperature is not enough to ensure its full use. The high difference in temperature between the metal and the slag does not allow the waste removal process to be as simple as possible. As another disadvantage, it is customary to highlight the gap, due to which it is always necessary to reduce the thickness of the lining. Due to such actions, after some time it may become faulty.

Use of induction furnaces on an industrial scale

In industry, crucible and channel induction furnaces are most often found. In the first, melting of any metals in arbitrary quantities is carried out. Containers for metal in such variants can hold up to several tons of metal. Of course, in this case it is impossible to make induction melting furnaces with your own hands. Channel furnaces are designed for smelting various types of non-ferrous metals, as well as cast iron.

This topic is often of interest to fans of radio design and radio technology. Now it is becoming clear that creating induction furnaces with your own hands is quite possible, and many people have managed to do this. However, to create such equipment, it is necessary to implement the operation of an electrical circuit that would contain the prescribed actions of the furnace itself. Such solutions require the involvement of those capable of producing wave oscillations. A simple do-it-yourself induction furnace according to the circuit can be built using four electronic lamps in combination with one neon lamp, which gives a signal that the system is ready for operation.

In this case, the AC capacitor handle is not located inside the appliance. Thanks to this, you can create an induction furnace with your own hands. The device diagram describes in detail the location of each individual element. You can make sure that the device is powerful enough by using a screwdriver, which should reach a red-hot state in just a few seconds.

Peculiarities

If you are creating an induction furnace with your own hands, the operating principle and assembly of which is studied and carried out according to the appropriate scheme, you should know that the melting rate in this case may be affected by one or more factors listed below:

Pulse frequency;

Hysteresis losses;

Generating power;

The period of heat release;

Losses associated with the occurrence of eddy currents.

If you are planning to build an induction stove with your own hands, then when using lamps you need to remember that their power should be distributed so that four pieces are enough. When using a rectifier, you will get a network of approximately 220 V.

Household use of stoves

In everyday life, such devices are used quite rarely, although similar technologies can be found in heating systems. They can be seen in the form of microwave ovens and In the environment of new technologies, this development has found wide application. For example, the use of eddy currents in induction cookers allows you to cook a huge variety of dishes. Since they take very little time to heat up, the burner cannot be turned on if nothing is standing on it. However, special utensils are required to use such special and useful cookers.

Build process

Do-it-yourself induction consists of an inductor, which is a solenoid made from a water-cooled copper tube and a crucible, which can be made of ceramic materials, and sometimes of steel, graphite and others. In such a device you can smelt cast iron, steel, precious metals, aluminum, copper, magnesium. Do-it-yourself induction furnaces are made with a crucible capacity from a couple of kilograms to several tons. They can be vacuum, gas-filled, open and compressor. The furnaces are powered by high, medium and low frequency currents.

So, if you are interested in making your own induction furnace, the scheme involves the use of the following main components: a melting bath and an induction unit, which includes a hearth stone, an inductor and a magnetic core. A channel furnace differs from a crucible furnace in that electromagnetic energy is converted into thermal energy in the heat release channel, in which there must always be an electrically conductive body. To make the initial start-up of a channel furnace, molten metal is poured into it or a template made of a material that can be straightened in the furnace is inserted. When the melting is completed, the metal is not completely drained, but a “swamp” remains, intended to fill the heat release channel for future start-up. If you are going to build an induction furnace with your own hands, then to make it easier to replace the hearth stone for the equipment, it is made detachable.

Furnace components

So, if you are interested in making a mini induction oven with your own hands, then it is important to know that its main element is the heating coil. In the case of a homemade version, it is enough to use an inductor made of a bare copper tube, the diameter of which is 10 mm. For the inductor, an internal diameter of 80-150 mm is used, and the number of turns is 8-10. It is important that the turns do not touch, and the distance between them is 5-7 mm. Parts of the inductor should not come into contact with its screen; the minimum gap should be 50 mm.

If you are planning to make an induction furnace with your own hands, then you should know that on an industrial scale, water or antifreeze is used to cool the inductors. In the case of low power and short-term operation of the device being created, you can do without cooling. But during operation, the inductor gets very hot, and scale on copper can not only sharply reduce the efficiency of the device, but also lead to a complete loss of its performance. It is impossible to make a cooled inductor on your own, so it will need to be replaced regularly. You cannot use forced air cooling, since the fan housing placed close to the coil will “attract” EMF, which will lead to overheating and a decrease in the efficiency of the furnace.

Generator

When assembling an induction furnace with your own hands, the circuit involves the use of such an important element as an alternating current generator. You should not try to make a stove if you do not know the basics of radio electronics at least at the level of a semi-skilled radio amateur. The choice of generator circuit should be such that it does not produce a hard current spectrum.

Using Induction Furnaces

This type of equipment is widely used in areas such as foundries, where the metal has already been cleaned and needs to be given a specific shape. You can also get some alloys. They have also become widespread in jewelry production. The simple principle of operation and the possibility of assembling an induction furnace with your own hands allow you to increase the profitability of its use. For this area, devices with a crucible capacity of up to 5 kilograms can be used. For small productions this option will be optimal.

A tabletop melting furnace is made with your own hands from simple and quite affordable materials: graphite, mica and asbestos tiles. Due to the fact that asbestos is prohibited for medical reasons and is becoming rare, it can be replaced with tiles or cement tiles.

The dimensions of the furnace are not strictly defined. It all depends on the power of the existing electrical network and the output voltage of the transformer. The higher the output voltage, the wider the distance between the electrodes should be. With the dimensions of the electric furnace indicated in the drawing, it is enough to apply 25-30 volts to the electrodes: the furnace heats up smoothly, but quite intensely. In the case of using an industrial welding transformer, which usually produces 50-60 volts, the distance between the electrodes must be approximately doubled, to 150-200 mm. In the furnace volume shown in the drawing (100x65x50 mm), you can melt 60-80 grams, for example, of silver, which is considered a good result.

Brushes from a powerful electric motor are suitable as electrodes for the furnace. They are convenient because they have a good current-carrying flexible wire. If it is not possible to get such electrodes, it is easy to cut them out yourself from a piece of graphite, for example, from a used electrode rod used in arc melting furnaces. In a homemade electrode, you just need to drill two holes with a diameter of 5-6 mm on the side, insert a stranded copper wire 5 mm thick into them and carefully hammer in another suitable nail to seal it. A mesh notch is made with a file on the inside of the electrodes to improve contact with graphite powder.

Mica is used as the inner lining layer of the furnace walls: due to its layering, it serves as a good heat-insulating screen. The outer walls are additionally reinforced with asbestos or cement tiles 5-10 mm thick. To make assembly extremely easy, the walls are tied with soft copper or binding wire. An ordinary brick serves as an insulating support for the stove; An enameled metal tray with sides is also placed underneath.
Carbon graphite powder can be obtained from used rods using a coarse file or a multi-blade metal hacksaw. It should be taken into account that during the melting process, graphite powder gradually burns out and must be periodically added.

Fig.1. Tabletop melting furnace:
1 - carbon graphite powder; 2 - place of metal melting; 3 - wiring harness for the furnace body; 4 - mica lining; 5 - asbestos tiles; 6 - carbon-graphite electrode; 7 - current-carrying wire.

Step-down transformer 25 volts. The network winding contains 620 turns of enameled copper wire with a diameter of 1 mm. The step-down winding contains 70 turns of rectangular wire 4.2x2.8 mm in fiberglass insulation.
The assembled furnace is connected to the transformer with fairly thick copper wires (7-8 mm) with mandatory external insulation to avoid accidental short circuits during operation.

When the oven is ready for use, it must first be properly heated to allow organic inclusions to burn out (while ensuring adequate ventilation in the room). In the future, the stove operates practically without the release of soot and burning.
Melting of metals is carried out according to the following scheme. First, using a small spatula, make a hole in the powder in the middle of the furnace, place the first portion of metal in it and bury it. If the scrap used is of different sizes, then the largest piece is placed first, and only after it has melted, small parts are added.

To make sure that the metal has melted, the furnace can be slightly shaken - in this case, the surface of the powder also begins to ripple. After the metal has cooled, it is turned over and melted again. This is repeated several times until the workpiece takes on a more or less spherical shape, indicating the quality of the melt.

When it is necessary to melt small shavings or sawdust of simple metals, they are poured directly into the hole and melted as usual. The more precious metal, in order to preserve it, is placed in a glass medicine ampoule and melted along with it. The glass crust formed by the melt easily crumbles when cooled in water.
Low-melting metals - tin, aluminum and the like - are best placed in an iron cup. To obtain alloys, a more refractory metal is first put into powder, and after it has melted, a low-melting metal is added. For example: copper + tin; copper + aluminum.

Fig.2. Transformer and connection diagram for a melting furnace.

In a melting furnace you can melt tin, aluminum, iron, nickel, copper, silver, gold, palladium. After melting, the resulting blanks are subject to forging. They need to be riveted on the anvil slowly, especially at the beginning, with a small hammer. And as often as possible, heat the workpiece until red hot on a gas stove, then cool it in cold water and rivet it again to the desired size.
It is strictly forbidden to melt magnesium, lead, cadmium, zinc and zinc-containing alloys (zinc brass, cupronickel), as well as silver contacts from various types of relays, devices, starters - they contain up to 50% cadmium, which burns out, forming yellow toxic smoke.

If it is not possible to purchase a powerful transformer, then it can be replaced with a composite one. To do this, you need to take several less powerful transformers of the same type and connect their output windings in parallel (provided that they are all designed for the same voltage). A homemade transformer is also possible. It is assembled from L-shaped permalloy plates with an internal section of 60x32 mm. Its network winding is wound with enameled wire 1 mm thick and contains 620 turns. The step-down winding is wound with a rectangular wire of 4.2x2.8 mm and contains 70 turns.

As for safety precautions when working with this furnace, we must remember that the welding transformer requires extremely careful handling. A short circuit must not be allowed to occur in the wires or between the electrodes in the furnace itself. The transformer mains switch should be located nearby so that it can be conveniently turned off at any second. You should also never leave a working stove unattended for a minute. There should always be a container of water nearby where hot workpieces are cooled.