Making a muffle furnace for melting and hardening metal with your own hands. Scrap metal furnace

If you want to melt metal and shape it into different shapes, you will need a furnace that can get hot enough to melt the metal. You can buy a ready-made stove or make your own from an airtight trash can. To start, cut the bucket to the right size and line the inside with heat-resistant insulating material. Then cover the lid with thermal insulation and fit it tightly so that it retains heat and excess pressure. Finally, install the heating element and you can melt metal!

Steps

Part 1

Furnace body

Use an angle grinder to cut a steel trash can so that it is 45 centimeters high. Find a steel trash can that is at least 45 centimeters high and at least 40 centimeters in diameter. If the bucket is taller than 45 centimeters, put a metal cutting wheel on the angle grinder and turn it on. Carefully trim the top edge of the bucket to the desired height.

When working with an angle grinder, wear protective goggles to protect your eyes from metal chips.
Be careful not to cut yourself on the sharp cut edges of the bin.
If you don't have an angle grinder or want to make a smaller oven, you can use a 10 liter steel bucket about 30 centimeters high.

Drill a hole in the side wall of the trash can at a distance of 10 centimeters from the bottom. Attach a 2.5 cm hole saw to the drill and clamp it tightly. Mark the location of the hole on the side of the bucket about 10 centimeters above the bottom. Drill through the side of the bucket.
- Air or other gas will enter the furnace through the side opening.
- Do not make a hole near the bottom, otherwise it may become clogged if liquid is spilled in the oven.
Line the inside of the bucket with a layer of ceramic fiber wool 2 inches thick. Ceramic fiber wadding has thermal insulation and refractory properties and is well suited for homemade stoves. Using a utility knife, cut a round piece of ceramic fiber wadding the same diameter as the bottom of the trash can. Push this piece into the bucket and press it firmly into the bottom. Then wrap the cotton wool tightly around the inside of the side walls of the trash can.
- Ceramic fiber wool can be purchased at a hardware store or ordered online.
- Ceramic fiber wool may cause irritation if it comes into contact with the skin. To avoid this, wear long sleeves and work gloves.
Warning: When cutting ceramic fiber wool, dust is released that can be harmful if it enters the lungs, so be sure to wear a respirator.

Cut out the cotton wool where it covers the hole in the trash can. Find the hole you made in the side of the trash can and use a utility knife to cut out the cotton wool. To do this, run a knife along the edge of the hole. After you cut the cotton around the entire circumference, pull it out of the hole.

Spray the cotton wool with a hardener and wait 24 hours. The hardener is a chemical compound that activates the ceramic wool particles, causing it to become harder and retain its shape. Pour the hardener into a spray bottle and apply it to the entire surface of the cotton wool. Allow at least 24 hours for the hardener to air dry and harden the wool layer.
- The hardener can be ordered online.
- Label the bottle you used for the hardener so you don't confuse it with other bottles.
- Some types of ceramic wool are already treated with a hardener and begin to harden in air. Check the cotton packaging for any indication of this.
Apply kiln cement to the surface of the wool and let it harden completely. Stir the kiln cement with a stick to get a homogeneous mixture. After that, apply cement to the surface of the cotton wool with a paint brush with 5 cm bristles. It is necessary to cover the entire surface so that heat does not escape from the oven. Wait at least 24 hours for the cement to set before using the oven.
- Already diluted kiln cement can be purchased at a hardware store or ordered online.
- You can do without furnace cement, but it will help to extend the life of the furnace and get a smooth, clean surface.
Part 2
Cover thermal insulation
1. Drill a 5cm diameter vent hole in the lid of the trash can. Take the lid to the bucket you used for the stove body. Attach a 5cm diameter hole saw to the drill and grip it tightly. Drill a vent hole in the lid 7.5 to 10 centimeters away from the handle.
  - Use a hole saw designed for drilling in metal so as not to damage the tool.
  - Never use a lid that does not have a ventilation hole, otherwise the increased pressure inside the oven may cause it to explode and collapse.
2. Fill the bottom of the lid with a 5cm layer of ceramic wool. Cut out a round piece of ceramic fiber wool 2.5 to 5 centimeters in diameter larger than the bottom of the lid. Press the cotton into the bottom of the lid so that it is pressed against the sides and held firmly in place. Continue adding layers of ceramic wool until it is 2 inches thick to ensure maximum heat resistance.
  - Wear long sleeves and an N95 or better respirator when handling ceramic wool to prevent irritation and itching.
  - Be sure to read the label on ceramic wool and follow all recommended precautions.
  - If ceramic wool does not stick to the bottom of the lid, you can pre-spray heat-resistant glue on it. Heat-resistant adhesive can be purchased at a hardware store or ordered online.
3. Cut out the cotton wool where it covers the hole in the lid. Turn the lid upside down and find the hole you drilled in it. Slide the utility knife along the edge of the hole and pierce the cotton wool with it. Cut the cotton along the edge of the hole and remove the cut piece.
  - The hole in the lid must not be covered with cotton wool, otherwise the oven will not have the necessary ventilation.
  Advice: If you find it difficult to cut the cotton in the hole with a utility knife, try using a serrated bread knife - they may be easier to cut through the cotton.
4. Apply a hardener to the cotton wool and leave it to harden for 24 hours. Pour the hardener into a spray bottle and apply it directly to the ceramic wool at the bottom of the cap. Coat the entire surface of the cotton wool with the hardener so that it hardens properly. After you apply the hardener to the cotton wool, leave the lid on for at least 24 hours in a well-ventilated area to let it harden.
  - If you don't have a spray bottle handy, you can apply the hardener with a paint brush.
5. Apply oven cement to the entire surface of the wool for better thermal insulation. Stir the kiln cement with a stick to get a homogeneous mixture. Using a 5 cm brush, apply cement to the outer surface of the cotton wool. Smooth out the cement with a brush and let it set for at least 24 hours.
  - Before applying the cement, place a sheet of cardboard or napkins under the lid so as not to stain the work surface.
Part 3
Heating element
1. Pass a steel pipe or nozzle through the hole in the oven wall. The type of pipe depends on what you are going to use as a heat source. If you want to heat the stove with charcoal, pass a steel pipe 30 centimeters long and 2.5 centimeters in diameter through the hole. In this case, the pipe should protrude from the inner wall of the furnace by at least 3 centimeters. If you are going to use propane, place the burner inside the oven and thread the end of the valve through the side hole. Position the end of the burner inside the oven so that it points away from the center.
  - Propane stove burners can be ordered online.
  - Do not use a regular steel pipe for propane, as this will make it difficult for you to control the flame.
2. - Any propane tank can be connected to the stove, but keep in mind that small tanks will run out of gas faster.
3. Preheat the oven. If you are using charcoal, fill the bottom of the oven 5-8 centimeters with briquettes and light them with a lighter. Turn on the blower at minimum power to heat up the oven. If you are using propane, open the valves on the tank and burner. Stick your lighter in the middle of the stove and ignite the propane. Cover the oven with a lid to prevent heat from escaping.
  - Regulate the intensity of the flame with the valves on the propane tank and burner.
  - The flame may come out of the vent in the lid, so be careful.
  - As a rule, charcoal stoves can be heated up to about 650 °C, while when using propane, the temperature can reach 1250 °C.
4. Melt the metal in the crucible. A crucible is a metal container inside a furnace that contains molten metal. Place the metal you want to melt into the crucible and place it in the center of the furnace using heat-resistant tongs. Wait for the furnace to heat up the crucible and melt the metal, and then remove it with tongs to pour it into the mold.
  - Using such a furnace, low-melting metals, such as aluminum or brass, can be melted.

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Unlike industrial equipment, a homemade metal melting furnace is a compact fixture. On such portable equipment, it is possible to smelt, harden or melt non-ferrous metals.

The furnace for melting metal is a body made of fireclay bricks. The binding element is clay. The fire chamber is intended for burning of coal. A hole is provided at the bottom through which air is blown into the ashes. Below is a cast-iron grate, which is called a grate. Coke or coal is laid out on it. It can be removed from the old furnace. Sometimes a refractory brick, when forming the body, is laid on the edge. The finished structure is fastened outside with a metal belt.

The furnace for remelting metals must have a crucible. It can be an enameled or cast iron cauldron. The location of the crucible is next to the burning coke. In order to improve the blowing, a fan is installed nearby. The equipment is used for steel smelting, but can be used as an iron smelting furnace.

Electric furnaces for metal melting

The basis of such a furnace is asbestos, which can be replaced with tiles. Do-it-yourself electrodes installed in the melting furnace must have a voltage of 25 V.

They are made in the following order:

They are machined from the brushes of an electric motor.
The assembly drilled holes 6 mm.
They pass a wire with a cross section of 5 mm.
A nail is driven in to secure the wiring.
In order to improve contact with graphite, a file, notches are made.

As a heat insulator, mica is laid out inside the furnace. When connecting to the network, a step-down transformer must be used. After manufacturing, the furnace turns on and runs for some time in idle mode.

Muffle furnace

Muffle furnaces are often used for heat treatment of parts. Such equipment is characterized by a large temperature range, from 20 to 1000 degrees.

The muffle furnace for metal hardening works on different types of energy. However, at home it is better to use a unit that runs on electricity. Hardening is carried out in the furnace muffle.

A do-it-yourself muffle furnace is made in several stages:

The muffle is made from fireclay bricks. Due to the round shape of the furnace body, their corners are bevelled. Grooves are selected in each brick, where the spiral is being laid.
If the muffle furnace for melting is made from an oven, then inside it is lined with fire-resistant bricks. Grooves for the spiral are cut in the masonry.
The chamber, made of refractory bricks, is placed in a case made of steel. The bottom is insulated. The gap between the side walls of the chamber and the housing is 4 cm, where the insulation is inserted. The top consists of 2 layers of metal and insulation.
Holes are drilled in the case, and through them the ends of the spiral are brought out, which are connected to the network cable.
In the case of using an oven, a heater is not required. It's already included in it.

aluminum smelting

Making an aluminum melting furnace with your own hands is a real thing. In industrial production, units with the name - carousel type furnaces - are very expensive.

To understand how to make an aluminum melting furnace, you need to understand their principle of operation. There are several types where non-ferrous metal is melted.

mini oven

A car disk is taken and buried in the ground so that the upper cut does not protrude. A hole for the pipe is made in the middle. One end is passed into the hole, and the other is brought out. A cooler is put on it to pump air. The smelter is filled with coals and aluminum scrap. Air is supplied and the temperature rises.

metal tank

You can make an aluminum furnace from a metal tank. For example, top-loading washing machine bodies. The interior of the structure is lined with refractory bricks. An air supply pipe is mounted below. Thus, portable equipment is obtained.

From a bottle

One of the unusual ways in which aluminum is melted. Nichrome wire is wound around the bottle. Previously, the surface of the bottle is lubricated with oil. A mixture of liquid glass and clay is applied on top. Drying is carried out within a week. Then another layer of wire is wound and clay is applied. After 7 days, the bottle is removed and only the heat-resistant shell remains. Voltage is connected to the ends of the wire for incandescent nichrome, and raw materials are loaded into the hearth.

Lead smelting

The lead smelting electric furnace consists of the following elements:

A round casing made of stainless steel, inside of which a heater is laid. It is attached to the wall with brackets.
An industrial TEN is supplied from below.
At the top is a rotary valve.
The sensor, which is located at a distance of 3 cm from the bottom.
The temperature controller is on the side.

By setting the regulator to a certain temperature, we warm up the device. The lead inside melts. At the end of the melt, a mold is brought under the bottom and the valve opens. Molten lead fills the interior of the mold.

Copper smelting

At home, foam concrete can be used to melt copper. 2 cylinders are cut from such material, with a diameter of 100 mm. The height of one is 100 mm, and the second is 15. Putting one on top of the other, a hole with a diameter of 15 mm is drilled in the middle. In the larger cylinder, in the middle, a hole is made in the form of a funnel to a depth of 85 mm. In the middle of the cylinder, on the outside, a groove is cut and a wire tie is carried out. It is needed so that the part does not fall apart from the temperature.

On the gas stove, an adapter is placed. A larger cylinder is placed on top so that the conical funnel is directed upwards. From above it is covered with a small cylinder with a hole. Lighting the burner, lower a piece of copper rod into a small hole until it stops against the wall of the funnel. After a minute, the rod will melt.

Smelting gold and silver

A gold melting furnace is easy to make at home. It is also applicable to the melting of silver.

The order of work is as follows:

A fireclay brick is taken and cut into 2 parts. With a Pobedite drill with a diameter of 48 mm, a through hole is made in one half, in the middle. And in the second hole is drilled at half the height.
A spiral is drawn through the hole and both halves are pulled together with bolts, holes for which are drilled from the sides.
A graphite crucible is placed on top.
A metal frame is made and both halves are inserted into it.
All side gaps are covered with clay.
A voltage is applied to the output ends of the spiral.
Pieces of gold or silver are thrown into the crucible.
During the heating process, non-ferrous metal is melted.

Making furnaces for melting metal with your own hands is a complex process, but doable. To do this, you need to study the characteristics of the types of equipment. Decide which of them is most preferable to given conditions. The production costs will quickly pay for themselves.

The approximate melting point of aluminum is about 660 degrees Celsius, which allows melting even at home. Of course, it will not be possible to reach such a temperature on a gas stove, and it is highly undesirable to carry out such work indoors. There are many videos on the Internet, how to do it yourself. In this article we will consider 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 unacceptably large amount of space. Aluminum is the most common metal on Earth, so the industry in this direction has moved far ahead. There are many types. For example, inclined cylindrical furnaces, furnaces with reverberating crucible, carousel furnaces and others.

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

In essence, the principle of operation of all home-made stoves is simple and of the same type. Differences, as a rule, only in their some design features. In some volumetric heat-resistant vessel fired up charcoal(this is the most successful fuel option for aluminum melting), into or over which in the crucible is placed the metal itself. The crucible can be, for example, trimmed fire extinguisher body, or even ordinary steel teapot. To increase the temperature of coals, high-quality air blowing from all sides is necessary (so that aluminum is heated evenly in the container). As a rule, oxygen is supplied through a pipe down the “well”. cravings an ordinary vacuum cleaner, an engine from an old hood, a cooler or even a hair dryer can create it. In principle, these are the necessary conditions for creating a kind of mini-smelter with your own hands.

Wheel disc mini oven

It is very easy to make this model. 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 ground. In the middle of the disk inside the resulting firebox there should be a hole through which we pass bent pipe, which exits next to the smelter. Through it, oxygen will flow into the mini-oven from below. Useful 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. It is convenient to use car disc brake welded over the pipe. After that, coals can be poured into the resulting mini-smelter and air can be supplied, raising their temperature. Aluminum scrap in the crucible is placed among the coals.

Metal tank oven

It is not necessary for the stove to be sunk into the ground. Easy to make by hand and portable oven. For this, any cylindrical tank made of heat-resistant metal, for example, a tank from an old top-loading washing machine. From the inside, the diameter of the tank is reduced by bricks and clay. Thus, the thickness of our furnace will be 10-15 centimeters. Do not forget to mount a pipe for inflation at the bottom of the case. Air can be supplied to it in any convenient way. Aluminum Raw Crucible hung inside the firebox. As you can see, there are no fundamental differences from the previous version. It is just as easy to make it with your own hands, the differences are only in the necessary tools and details.

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. Furnaces for melting a large amount of metal are installed at the production facility. At home, you can assemble a furnace for melting up to five kilograms of aluminum. Consider how to make a smelter at home.

Equipment and materials you will need

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

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

Dimensions will vary from the desire of the person who collects it. It is better to create a small furnace for melting metals if you want to use it only for your own needs. You will spend less time on its manufacture, and a small number of kilowatts will be spent on heating it. If you are doing it on diesel fuel or on coal, then do not forget about installing thermal insulation and air blowing.

Metals such as iron, nickel, tin, copper are melted in an electric furnace. The output voltage in the electric furnace should be greater, which means that 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 alternator is installed.
Spiral winding. Made from copper wire.
Crucible.

All these elements are placed in one case. The melting cup is placed in the inductor. The winding is connected to a 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.

The positive properties of the induction furnace are that during the remelting of metals a homogeneous melt is obtained, alloying components do not evaporate, and melting occurs rather quickly. In addition, the installation of such a furnace does not harm the ecosystem and is safe for those who use it.

Cooling can be done with a fan. Only the latter should be located as far as possible from the furnace, otherwise its winding will serve as an additional closure of vortex flows. This will reduce the quality of the melt.

Features of melting of some metals

In order to melt metal at home, this element must be placed in a small cup or crucible. The cup with the material is inserted into the oven. Then his melting begins. To melt precious elements, they are placed in a glass ampoule. In order to make an alloy of several components, follow these instructions:

First, a refractory element - copper or iron - is placed in a cup for melting.
Then a more fusible component is placed - tin, aluminum.

Steel is a refractory material. Its melting point is one thousand four hundred degrees Celsius. Therefore, in order to melt steel at home, you must follow the following instructions:

To melt steel at home, introduce additional regenerators. If the stove is powered by electricity, then electricity is used.
During induction heating, slags are added. They increase the speed of melting.
Constantly monitor instrument readings. If necessary, lower the melting temperature, switching to a more moderate mode.
It is always correct to determine whether the steel is ready for work or for melting. Follow all of the above steps. Only then will the output metal be of high quality.

To melt iron at home, the furnace must be preheated. First, a large piece is placed, and then small ones. Iron must be turned over in time. A properly molten metal will have a spherical shape.

If you are going to make bronze, then you first need to place copper in the melting hole. Since this component is more refractory. When copper is melted, tin is added.

Under no circumstances should elements such as cadmium, lead or zinc be melted. When burnt out, they form a poisonous yellowish smoke.

And when melting aluminium, tin or iron, it is necessary to observe slowness. Rivet slowly and do this with a small hammer. Frequently heat material until red and cool in cold water. Only then will you get the perfect alloy at the end.