Induction furnaces for metal melting. How to make a furnace for melting metal Do-it-yourself home melting furnace

homemade ornamental plant, which is shown in the video, is actually a skillfully disguised smelter. This idea will be a real find for those who work with metal from time to time to make another craft from aluminum or other metal on this one, but there is not enough space in the workshop or at home to have a place for every thing.

You will find some inventions for yourself in this Chinese store.

Required funds.

In this project, we use equal proportions of sand and gypsum to make a simple smelter, powerful enough to melt scrap metal in a second and nice to look at so you don't have to hide it. This is a mini metal smelter.

First we need large bags of sand and plaster. Both can be purchased at hardware store. We also need a 9 and a half liter metal bucket and a blanket to cover the workplace with it, because, most likely, we will get it a little dirty. A two and a half liter bucket can be used as a measuring stick, but you will soon see that it has an even more important meaning.

For our refractory lining, we use the following recipe: 4.2 liters of gypsum, 4.2 liters of sand, and 3 liters of water. When the water comes into contact with the dry mix, a countdown will begin. We will have about 15. So, let's start mixing everything. It is very important that all the dry mixture gets wet, get rid of lumps as quickly as possible.

After a couple of minutes of mixing, the mixture should be quite liquid and about the same color. After making sure that there are no lumps left, we proceed to the transfusion. Carefully pour the mixture into a metal pail, being careful not to spill anything. The mixture is enough to fill the bucket, leaving about 8 cm on top.

Now we can take the plastic measuring bucket and use it to form the center of the smelter. You can fill it with water to give it weight, but sand or rocks will also work. When we push the bucket in, the mixture rises but does not pour out. The mixture has already begun to harden. So let's move the bucket up and down to level it. You need to hold the bucket in this position for 2-3 minutes, during which time the plaster will harden enough for the bucket to remain in place.

It takes about one hour to completely harden, but the plaster is soft enough to trim it. If you dampen a rag and gently run it over the top, you can trim the plaster very well and give it a nice texture. When you're done, leave everything to dry for about an hour.

Melting crucible from a fire extinguisher.

Why not turn that old fire extinguisher into a melting pot? You can understand that it is made of steel, because if you bring a magnet, it is attracted. This does not happen with aluminum.

After depressurizing the cylinder, we unscrew the top valve to easily and safely cut it with a hacksaw, which took less than a minute. For the crucible we will use lower part, because it is essentially a steel container 8 cm in diameter and 13 cm high. Good size for our homemade mini-smelter.

At this point, the plaster should have hardened well. Let's pour out the water. Next, use tongs or something similar to gently pull one side of the bucket towards the center. Now, if you grab it with both hands and twist a little, the bucket will come loose and be easy to pull out.

We got amazing smooth surface, thanks to which our homemade smelter looks surprisingly professional.

Hole for air supply.

All we need is an air inlet and a cover. Let's take care of them. A three and a half centimeter hole saw attachment is great for this tube. If you set the center of the nozzle on the top line of the bucket, you can begin to carefully cut through the metal. When we pass through the metal, we need to tilt the tool down about 30 cm, which is easy because the plaster is not yet completely hardened and cuts like butter. We now have a hole that fits perfectly into the blower tube. It will be placed a few centimeters from the bottom.

Blower.

Now, if the crucible fails and pours out the molten metal, in the smelter the metal remains inside, and will not pour out through the tube. The blower is very easy to make. First you need to take a 3 cm tube, it will be next to hot coals.

You will also need a 3 cm PVC tube. As you can see, the thread from one end of the coupling is screwed onto a metal tube, and the adapter on the other side is simply screwed onto a PVC tube.

Lid.

Let's go even further. Let's make a lid that will help keep the temperature. We need a couple of 10 cm U-bolts. Place them vertically in a wide bucket filled with half the initial volume of our mixture. After an hour, the gypsum will harden and can be easily removed from the bucket. And now the cover for the smelter is ready.

Pressure relief hole.

You need to make a hole for pressure relief. it can be made before hardening, but can be drilled with a drill with an 8 centimeter nozzle. When the hole is done, you will have a lid that looks like a huge donut. This design allows you to relieve pressure and melt the metal without even removing the cover.

Conclusion.

If you build a fire, you can see that it gets so hot inside that the soda can melts in a second and the crucible is filled with liquid aluminum. With a mini-smelter like this, we can smelt aluminum in our yard and cast whatever we can think of.

Best of all, when you're not smelting scrap, the smelter doesn't take up space and doesn't stand out. You can insert a plant pot inside and instantly turn it into part of the decor. This pot-turning foundry is more than meets the eye. Only make your smelter stable This is extremely important for safety.

By the way, you can try to apply the melting furnace as forge or even as a barbecue, because after all it runs on coal.

Now you know how out wide available materials make a mini smelter powerful enough to smelt metal in seconds, yet nice enough to look at so you don't have to hide it. Translated and voiced by the Science and Technology channel.

In another publication, another useful pro.

A muffle furnace for melting or hardening metal products is a device that allows home master do a certain job. A simple unit that can work on different types fuel, for self-manufacturing It is enough to have the skills to perform metalwork and electric welding.

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Device and circuit

Device muffle furnace for melting metal consists of:

in most cases steel case. For home use it is better to make it from heat-resistant metal or stainless steel. But you can use structural steel. Sheet thickness 1.5-2 mm;
layer internal thermal insulation. Used for home ovens fireclay brick or other thermal insulation material, which can withstand heating temperatures up to 1000 0 - 1200 0 ;
steel body can be overlaid with an outer layer ceramic tiles or refractory bricks;
electric or gas heating elements. Gas-burners it is better to buy in specialized stores. An electric oven can be equipped with homemade nichrome or fechral spirals. Wire thickness - 1 mm. Fechral wire is cheaper, but it is inferior to nichrome in terms of resistance to aggressive environments and the durability of the spiral;
system of automatic or manual control of the operation of equipment. By installing thermal sensors, you can easily control temperature regime and time to maintain the set temperature.

Output

Homemade or industrial furnaces for hardening metal or melting it - all these designs should ensure safety and comfort in working with heating devices. It is not difficult to make a design on your own, even a beginner can handle it. The main thing is to carefully and responsibly follow all the recommendations and rules for performing work.

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If you want to melt metal and give it different shape, you will need an oven that can heat up to enough high temperature to melt the metal. You can buy a ready-made stove or make your own from an airtight trash can. To begin, cut the bucket so that it has suitable sizes, and line the inner surface with heat-resistant insulating material. Then cover the cover with thermal insulation and fit it tightly so that it retains heat and overpressure. Finally install heating element and you can melt metal!

Steps

Part 1

Furnace body

Trim with a corner grinder a steel trash can so that its height is 45 centimeters. 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 side wall buckets through.
- 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. Wool made of ceramic fiber has thermal insulation and refractory properties and well suited for homemade stoves. Via 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 tightly with cotton inside 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.
A 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 through the hole in the oven wall steel pipe or nozzle. 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.

A homemade melting furnace can be made from graphite, cement, mica, or tiles. The dimensions of the furnace depend on the power supply and the voltage of the transformer at the output.

A homemade melting furnace heats up gradually, but reaches a significant heat. For this design, it is necessary to set a voltage of 25 V on the electrodes. If an industrial transformer is used in the design, then the distance between the electrodes should be 160-180 mm.

The process of making a homemade melting furnace

You can make a melting furnace with your own hands. Its dimensions will be 100x65x50 mm. In this design, 70-80 g of silver or other metal can be melted. Such opportunities for a homemade melting device are very good.

Materials and tools:

brushes from a high power electric motor;
graphite;
electrode rods used in arc furnaces;
copper wire;
nails;
mica;
cement tiles;
brick;
metal pan;
carbon graphite powder;
thin conductive wire;
transformer;
file.

To make a melting furnace with your own hands, brushes from a high-power electric motor can be used for electrodes. They have an excellent current-carrying wire.

If you cannot purchase such brushes, then you can make them yourself from a piece of graphite. You can use a rod electrode, which is used in arc furnaces.

On the sides in this rod, it is necessary to make 2 holes with a diameter of 5 mm, then, to give strength, carefully drive a nail of a suitable size into it. To improve contact with graphite powder with a file, it is necessary to make a mesh notch on inner surface these electrodes.

For the manufacture of the inner surface of the walls of the stove, mica is used. It has a layered structure and can therefore be used as a good heat shield.

Outside, the surface of the structure must be covered with cement or asbestos tiles, which have a thickness of 6-8 mm. After mounting the walls, they must be tied with copper wire.

A brick must be used as an insulating stand for the device. A metal tray is installed below. It should be enameled and have sides on the sides.

Then you need to make carbon graphite powder. It can be prepared from unnecessary rods. Work is best done with a file or a hacksaw for metal.

When using the stove, graphite powder gradually burns out, so it needs to be topped up sometimes.

To operate the device, a step-down transformer with a voltage of 25 V is used.

In this case, the network winding of the transformer must have 620 turns copper wire which has a diameter of 1 mm. In turn, the step-down winding should have 70 turns of copper wire. This wire must be insulated with fiberglass and rectangular section dimensions 4.2x2.8 mm.

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How to make a transformer?

If you can't buy a transformer with a high enough power, you can make one from several similar transformers with lower power. They must be designed for the same voltage in the network.

To this end, it is necessary to connect the output windings of these transformers in parallel.

Can be made. To do this, it is necessary to prepare L-shaped metal plates having an internal section of 60x32 mm. The network winding of such a transformer is made of enameled wire with a cross section of 1 mm. It should have 620 turns. In this case, the lowering winding is made of a wire having a rectangular cross section with dimensions of 4.2x2.8 mm. It should have 70 turns.

After installing the furnace, it is connected to the transformer using a copper wire having a thickness of 7-8 mm. The wire must have an outer insulation so that a short circuit does not occur during the operation of the furnace.

When the oven is fully ready for operation, it must be well warmed up. At the same time, they should burn out organic matter within the structure. During this procedure, the room should be well ventilated.

The device will work without soot. After that, the operation of the furnace is checked. If everything works fine, then you can start using the device.

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How is metal melted in a furnace?

Metal melting is performed as follows. With the help of a small spatula (in the center of the stove) in graphite powder, you need to make a small hole, put metal scrap there and drip it.

If the pieces of metal to be melted have various sizes, then first of all lay a large piece. After it melts, put small pieces.

In order to check whether the metal has already melted, you can shake the unit a little. If the powder sways, then the metal has melted.

After that, you need to wait until the workpiece has cooled down, then turn it over to the other side and melt it again.

This procedure must be repeated several times until the metal takes the form of a ball. In this case, it is considered that the melting of the metal is of high quality.

If it is necessary to melt sawdust or metal shavings of inexpensive metals, it is necessary to pour them into the hole of the powder and carry out the usual melting.

More expensive or precious metals should be put in a glass ampoule from under the medicines and melted together with this ampoule. In this case, a film of glass is formed on the surface of the molten metal, which can be easily removed by placing it in water.

Metals that melt easily should be placed in iron dishes. If you need to perform an alloy various metals, then the metal, which melts worse, is first placed in the furnace. After it melts, fusible is added. For example, to obtain an alloy of copper and tin, you must first put copper into the powder, and then tin. To obtain an alloy of copper and aluminum, copper is melted first, and then aluminum.

In this device, you can melt metals such as tin, iron, copper, aluminum, nickel, silver, gold. After melting the metal, it is forged. It is forged on an anvil with a hammer. In this case, it is often necessary to heat the workpiece red-hot on fire, and then again forge it with a hammer. After that, the metal is placed in cold water, and then hammered again until the workpiece acquires the required dimensions.

In no case should metals such as lead, magnesium, zinc, cadmium, cupronickel be melted, since, when burnt out, they form a very toxic yellow smoke, which has a detrimental effect on human health. Silver contacts from relays and other devices should not be melted because they contain up to 50% cadmium.

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. Smelting furnaces installed in production a large number metal. 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.

Positive properties induction furnace in the fact 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 furnace. 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 the material until it turns red and cool for cold water. Only then will you get the perfect alloy at the end.