Wooden decor elements are present in the homes of each of us. Sometimes we go to the store to buy a beautiful wooden frame or jewelry box for our home or as a gift to our loved ones, friends and relatives. However, the best gift is a gift made with your own hands, and to make a beautiful frame or box, we need a cutter or a nichrome electric jigsaw, which we will do right now.
Watch in the video how a nichrome cutter is made:
So, to make a cutter, we need a 12 volt 5-10A power supply (you can use a computer unit), nichrome wire with a cross section of 0.4-0.8 mm (you can disassemble a wire resistor or the same boiler that uses nichrome thread), two pieces of a cut branch , from which we will make handles, copper wire 1-1.5 m long, as well as two nails or two pieces of hard wire.
The first thing you need to take care of the handles. To do this, you need to drive a nail into pieces of a branch or stick a wire. For convenience, it is better to use a branch from a soft tree. When the wire or nail is inserted, you should take round-nose pliers and make rings from the protruding parts of the wire so that the wire itself, as well as the wires, do not slip off during twisting.
The next step is to take any yellow and black wires from the power supply and connect them to the copper wire, which will be the main one in our cutter, not forgetting the need to insulate the wires.
When you plug the power supply into an outlet, it will not start immediately. If you are using older models of computer units, then you can separately install the switch by connecting the green wire to any of the black ones. With new models, everything is much easier: it is enough to short-circuit the same two wires for a fraction of a second using an ordinary paper clip.
It's time for the most important part: choosing the right length of nichrome thread. In order to do this, you can use a special formula, but there is an easier method, which is known as the poke method. The required length of the thread can be determined by winding it around a wooden block, connect the positive wire to one end and gradually bring the negative wire closer from the other end until the thread starts to turn red.
Attention!!! If the length of the nichrome filament is incorrect, the power supply may overload and fail, and the filament may also quickly break.
After calculating the length of the thread, it remains only to cut off its excess part and wind it around two rings of two handles. On other rings, you should wind the wire from the power supply.
Polyfoam is used in many construction works. It has good thermal insulation. However, this is a rather fragile and crumbling material. Therefore, when cutting it, special equipment is used. Otherwise, the edges will be uneven, and the material itself will lose its thermal insulation qualities at the joints.
Special equipment is on sale. However foam cutter you can do it yourself. This will significantly save the family budget. How to create different options for a tool for cutting foam, it will be interesting for every craftsman to know.
Tool type
By creating manual foam cutter, you should study the existing varieties of this tool. There are mechanical and electrical varieties. If the foam product is small in size, and the cutting accuracy is not so important, you can give preference to the first version of the tool.
However, in order to ensure a tight fit of the foam plates to each other, it is necessary to ensure high cutting accuracy. The edges must be smooth. In this case, it is possible to create a high quality insulation layer. Its heat loss will be minimal. When cutting unevenly, large gaps form between the joints. Through them, the heat from the room will go outside.
Professional designers and builders use only electrical equipment for cutting foam. At home, it is quite possible to create a similar tool.
Simple electric cutter
Considering how to make a foam cutter, you should study the design of the simplest equipment of this class, which is powered by electricity. In this case, you will need to prepare a thin guitar string and several batteries (for example, from a flashlight).
The principle of operation of this equipment is simple. Battery construction forms a single unit. A guitar string is connected to it. When electric current passes through the circuit, it will heat up. It is in this state that the string can easily cut the foam sheet.
When using such a tool, the material will melt. The string heats up to 120 ºС and even more. In this case, it is quite possible to cut several large foam plates. If you need to perform a large amount of work, this option is not suitable. Batteries run out quickly. You will have to provide for the option of connecting the system to a household network.
Varieties of electric cutters
Electric foam cutter can be used for different purposes. This will depend on the type of construction and the overall performance of the equipment. There are three main types of homemade cutters.
The first category is used for linear cutting. The second group includes cutters that perform curly cutting of material. They are used by designers. To perform home repairs, this variety is used less frequently. There is also a tool with a metal working plate.
Such equipment necessarily has a step-down transformer in its circuit. It must be rated for a minimum power of 100 watts. The secondary winding of the transformer must have a cross section of at least 1.5 mm. It must withstand a voltage of 15 V. In this case, you can achieve a high result of work.
Features of work
studying, how to make a manual foam cutter, it is also necessary to consider the features of the functioning of such equipment. As mentioned above, such an instrument has a string. It heats up and melts the surface of the foam.
Such material reacts poorly to heat. Therefore, it is important to maintain the technology of the entire process. Cutting with a hot thread is fast. This allows you to achieve a high quality cut.
Checking the heat level of the string is easy. To do this, a test is carried out on a test piece of foam. If, when the thread is immersed, long pieces of material remain on it, it has not yet warmed up enough. If there is no foam on the string at all, then the temperature is too high. In this case, you will have to cool the tool a little. With the right heat, it is possible to perform fast, accurate cutting.
Cutter for linear cutting
Linear DIY foam cutter allows you to create blocks of material of the required dimensions. This greatly speeds up the work of the wizard. If necessary, this tool can cut circles, triangles or squares in the foam.
Two racks are vertically mounted on the surface of the table. Two insulators are attached to them. A nichrome thread is stretched between them. This alloy heats up quickly, providing sufficient cutting temperatures. A freely hanging load is passed through one of the racks. Contacts from the transformer are connected to the thread.
Passing the current will heat it up. It will be taut all the time due to the weight hanging from one side. This is necessary because the string can sag when heated. If desired, the design can be modified by adding a spring instead of a load. However, the original version is easier to implement.
Line cutting process
Considering how to make a styrofoam cutter with your own hands, you also need to understand how to work with them correctly. Cutting can be done vertically or horizontally. To do this, the thread is pulled in the appropriate position.
If the string is stretched horizontally, you can use it to make the same cuts. Styrofoam is evenly pulled across the table. The thread will evenly cut it into the required pieces.
When cutting the structure vertically, a metal or plywood frame is added. A holder is installed on it. An insulator and a nichrome string are supplied to it. On the other side, a load is suspended. It will go through a hole drilled in the table. It must be large enough and covered with a special insulating material. Next, you can perform vertical cutting.
Curly cutting
If you need to cut large enough sheets of foam or create decorative elements, sculptures from this material, a special type of equipment is used. You can also make it yourself. It's manual foam cutter. It is made on the basis of a manual jigsaw or hacksaw. In them, the cutting element is changed to a nichrome string.
If you want to create curly elements, you can make several tools of various shapes. A wire is connected to the handle of the jigsaw. It must be carefully isolated. Otherwise, it will be unsafe to work with this equipment. A nichrome string is attached to the wire contacts. This can be done with nuts and screws with washers.
Also, to create such equipment, an impulse soldering iron or a wood burner may be suitable. This tool is considered convenient. Their working element is removed from such equipment and replaced with a piece. In this case, the threads can be given a different shape.
Cutter with metal plate
Exists foam cutter, in the design of which it is used To create this equipment, you can remake a soldering iron. Suitable equipment with a power of 60 watts. Remove the heating element from the device. Instead, a plate is installed here.
One side of the copper blank needs to be sharpened. This will allow you to create a more precise cut. The sharpening angle should not be made too large. Cutting will be done by heating. To find its required level, you will have to experiment on a test piece of foam.
This method is also used by masters of various skill levels and profiles. If necessary, the copper plate can be replaced with a steel billet. This option will require more effort when sharpening. But with the help of such a tool, you can also cut denser polymeric materials.
Choosing which foam cutter more suitable for the work of the master, you should take into account the recommendations of professional builders. The greater the amount of work performed, the more complex the design will be. A simple battery-operated cutter is fine for cutting a few blocks. However, to perform a large amount of work, you should give preference to network types of equipment.
When cutting, the foam is heated. At this point, substances unsafe for human health are released from it into the environment. Therefore, work is performed in a well-ventilated room or on the street.
In order not to make a mistake with the cutting configuration, you should mark all the lines with a pencil before starting the action. This will help avoid cutting errors. These simple recommendations will allow you to do the job quickly, correctly and safely.
Having considered what options for foam cutters can be made with your own hands, each master will be able to choose the best option for himself.
Styrofoam is a versatile material. It is used in construction (insulation), in the production (repair) of household electrical appliances, interior design, advertising. One of the main characteristics of the material is density. The higher this value, the stronger the material. However, this greatly affects the price.
When using the material as a filler for wall insulation, the loosest structure is usually chosen (due to low cost). However, loose foam is difficult to process - when cutting, it crumbles a lot, making it difficult to clean up debris.
A foam cutting knife should be thin and sharp, but this does not prevent the edge from breaking. Even if you work outdoors, flying small balls litter the environment.
Therefore, professional builders cut the foam with nichrome wire or a hot plate. The material is fusible, despite the fire safety.
Important! When choosing a heater, pay attention to the characteristics. It should say "self-extinguishing". Such foam is perfectly cut with the help of temperature, but in case of fire it will not become a source of combustion..
An industrial foam cutting machine can process sheets of any size, cut material both across and along the array.
However, cutting foam at home does not involve such volumes and sizes. For repair work in your home (or garage), a compact thermal knife is quite enough. It can easily cope with both linear cutting and curly adjustment of plates, when laying in areas with complex shapes. 
Any tool has a cost, and there is always an opportunity to save money on a purchase.
Do-it-yourself foam cutting tools
For linear cutting, the guillotine is excellent. Only the impact will not be mechanical, otherwise a lot of garbage will be formed. We use a proven technology - cutting foam plastic with a tension heated string.
Required Materials
- Nichrome (tungsten) thread
- Power supply, preferably adjustable
- Any structural materials: beam, metal profile, pipe, for the manufacture of a tension frame
- Furniture guides for drawers.
On a table, workbench, or other flat surface, we install vertical racks for attaching the guillotine. With the help of furniture guides, we fix the frame of the cutter so that it moves without distortions. Both sides must move synchronously. 
The most critical part of the cutter is the wire mechanism. The first question is where to get the material. Nichrome can be purchased at stores selling radio components. But since we are striving for a shareware design, we will look for an alternative.
- Old soldering iron. Models made in the USSR, designed for 36-40 volts, can be found in any home workshop. The heater winding is an excellent donor for a nichrome guillotine. True, the length of the wire is not more than a meter.
- Iron with classic spiral heater. The wire is thicker, suitable for linear cutting. Curly cutting is acceptable, with low requirements for accuracy.
- Spiral heaters from a hair dryer, or a fan heater. The principle is the same, they are not suitable for precise cutting.
note
Tip: When straightening the spiral, do not pull the wire along the spring. Loops may appear and the thread will break. It is better to unwind the turns as from a spool of thread. You can put a spiral on a nail or pencil, and pull the wire across the turns.
The principle of operation of the frame is shown in the diagram.
The wire cutter must be electrically isolated from the frame. Therefore, it can be made of metal. It is important to keep the tension on the wire constant. When heated, nichrome expands, adding up to 3% in length. This causes the string to sag.
Styrofoam (extruded polystyrene foam) is used as thermal insulation for exterior and interior decoration, used for packaging goods or manufacturing prefabricated structures. The material is produced in the form of sheets, which are cut on the spot and adjusted to the dimensions of the surfaces. For quick cutting of foam, you will need a special device that allows you to make a straight or curly cut.
Manual processing of foam plastic is possible at home and in small workshops using a simple device assembled from improvised materials. Extruded polystyrene foam has a fairly dense structure, so you can cut the plates with a metal tool heated to a certain temperature. As a cutting surface, a wire that supplies electric current is suitable, with the supply of which the main difficulty in assembly is associated.
A self-made machine allows you to get tiles or bars of suitable thickness from ordinary foam for packaging with their further use in various structures. With such a device, you can also cut foam rubber or similar materials that are needed for the manufacture or repair of upholstered furniture. The compact dimensions of the device for cutting polystyrene with your own hands using nichrome allow you to install the machine in a small workshop or even on a balcony.
To cut foam at home, you will need a structure that can be assembled from simple materials available at any hardware store. First you need to determine the parameters of each element, taking into account the dimensions of the foam plates that will have to be processed . In most cases, the following details will suffice:
- The basis from dense plywood, a chipboard or the massif. You can order new parts or use elements of old furniture (doors, walls, shelves). A base of 400 x 600 mm is sufficient for working with foam.
- A string or wire in the form of a thermal knife for polystyrene.
- Metal posts, screws, springs or ordinary nails to fix the wire. The installation height of the cutter depends on the expected thickness of the finished boards.
- Fixings for parts on the base. A few self-tapping screws are enough to fix the structural elements.
To assemble a thermal cutter, it will take up to one hour of working time. Each of the structural elements can be quickly replaced in the process of repair or expansion of the fixture.
Action algorithm
To make a device for cutting foam or similar materials, you need the most common tools (hammer, screwdriver, pliers). You can work anywhere with enough space (balcony, room, hallway, garage, etc.). No involvement of assistants or third-party specialists is required.
Assembly is carried out in the following order:
Legs can be attached to the base, which will increase stability when cutting foam with a string.
How to choose cutting wire
A suitable cutter can be made from nichrome wire (X20H80), which is used in the design of most household appliances as a heating element. In terms of mechanical characteristics, nichrome is comparable to ordinary steel, while it has a high resistivity and a heating limit up to temperatures of +1200 ºC. Wire diameters up to 10 mm are available for the manufacture of cutting fixtures.
Precise and smooth foam carving is possible when the cutting line is heated to a temperature that is two to three times the melting threshold (+270 ºC). It should be borne in mind that such a process involves the consumption of energy and the absorption of heat by the material itself in proportion to its density. Therefore, for efficient and safe cutting, it is necessary to select a wire of suitable thickness in order to exclude metal melting at maximum heating.
Calculation and preparation of the electrical part
For the safe operation of the device, it is necessary to correctly mount the conductive elements that are connected to the power source through the captive terminals. To cut the material, you can use alternating or direct current. The power of the source is calculated based on the fact that up to 2.5 W will be needed for effective cutting of 10 mm wire (for 500 mm - 125 V).
The voltage is proportional to the resistance and is calculated using formulas or tables. But on average, with a wire diameter of 0.8 mm, a length of 500 mm and a resistance of 2.2 ohms, you will need a 12 V current source with a load current of 12 A. Changing the length up or down will require a similar increase or decrease in voltage at the same strength current.
Power sources and connection diagram
Safe cutting is ensured by connecting to a regular 220 V household network through a car transformer. To adjust the voltage in a single primary winding, a handle is provided, with which the graphite wheel is moved and the voltage is removed from the corresponding area. This parameter can be changed within the range from 0 to 240 V. Connection to the current source is carried out through the terminal box.
When connecting a homemade foam cutting machine to the mains, you need to make sure that the phase does not fall on a common wire. All the necessary parameters and connection diagram can be found on the transformer housing. Before connecting to the network, you need to check the operation of the device using a multimeter.
A simpler option for supplying current to the wire is to use conventional step-down transformers with taps from the secondary windings. In this case you don't have to adjust the voltage, since this value is always constant and sufficient to heat the wire to the desired temperature. You can select the desired value during the initial setup of the transformer, providing a certain number of turns of windings in the circuit.
You can also heat the wire for cutting polystyrene using household appliances. In this case, the following nuances are taken into account:
It must be taken into account that the cutting tool will immediately be hot when energized, so it should not be touched to check the temperature.
To make a thermal knife for polystyrene or foam rubber, it will not take a significant investment of time and effort. For this, a wire of almost any diameter is suitable, but with unknown parameters (diameter, resistance), you need to increase the power gradually, connecting first low-power current sources. Of great importance is the reliable isolation of the contacts and the control of the position of the phase, which cannot be connected to the wire.
The issue of home insulation is very relevant today. Sheathing the facades of houses with foam plastic is one of the most popular types of insulation. And this is very reasonable, because. the process of such insulation is simple and understandable, and all the necessary materials are always on sale.
But everyone knows that gluing foam is very convenient on a flat wall. With any method of gluing the foam to the wall: dry mix glue, foam or glue-foam, it is always very important that the foam sheet fits snugly against the wall and does not create air gaps.
If the wall is even, then no questions arise. But, unfortunately, the walls of old houses do not differ in ideal evenness. Yes, and different design features of the structure sometimes create drops on the plane of the wall.
Partially, this drawback can be leveled by laying the foam on a thicker layer of glue. But the maximum allowable thickness of the adhesive layer often cannot cover the magnitude of the differences in the plane of the walls. In addition, too large differences lead to unjustified overspending of glue.
The next way out of the situation remains - cutting the foam in thickness. But doing this with a hacksaw is very inconvenient and time consuming, especially if you need to cut a large amount of foam. In addition, during cutting, a large amount of debris in the form of foam balls is formed. Yes, and the surface is uneven and the accuracy of such cutting is very conditional.
In order to quickly and evenly cut the foam of the desired thickness, you can use a foam cutting machine. This device can be made independently, absolutely with your own hands.
The principle of operation and the device of the machine for cutting foam
The principle of operation of the machine is based on the fact that the foam is easily melted under the influence of temperature. Thus, if you draw a thin heated wire over it, it is easily cut, while forming a perfectly flat, smooth surface.
For the manufacture of the machine, the following components are needed:
- LATR (laboratory autotransformer) or car battery;
- nichrome thread;
- racks for attaching nichrome thread;
- spring (1-2 pcs.);
- tabletop board;
- copper wire.
A nichrome thread (spiral) is used as a cutting object. You can either buy it in a store or extract it from old household appliances in which they were used as filaments (a hair dryer, for example). The thickness of the spiral can be 0.5-1 mm. The most optimal thickness is 0.7 mm. The length depends on the width of the foam to be cut.
An important element of the device for cutting foam is LATR. But if it is not there, then it can be done using an old transformer and a device for charging car batteries.
You can also use a computer power supply that uses wires that give 12 watts (yellow and black) to connect to the spiral.
To operate such a machine, it is enough to have an output voltage of 6-12 watts.
It is necessary to correctly adjust the length and thickness of the filament and to match the voltage. If the thread is too hot, it may break. Well, if the thread is slightly heated, then cutting will be slow.
A car battery can also be used as a power source. They can be used in conditions where there is no electricity on the site.
For different tasks, you can make different designs of the foam cutting device.
Basically, these devices will differ in the length of the spiral. To cut foam into bars, a short spiral length is needed.
You can install two spirals and cut the sheet into several bars in one pass.
Two spirals cut the sheet into three parts in one pass. The stand is stuffed with guides for smooth feeding of the foam.
But, in extreme cases, foam plastic can be cut into bars with a hacksaw. It is much more difficult to cut the foam in thickness, and even with a given size. Therefore, we will consider how to make a machine for cutting foam in width.
Step-by-step instructions for self-manufacturing the machine and cutting foam
Step 1. Preparation of the countertop. As a tabletop for a do-it-yourself foam cutting machine, you can take any piece of chipboard of the right size. The surface on which the foam will move must be smooth. Holes for racks are drilled in the tabletop. It is convenient to use metal pins with a thread with a diameter of 10-12 mm as racks. The height of the racks should correspond to the thickness of the foam sheets plus a margin in height. The pin is fixed with nuts.
To give the structure stability, bars are attached to the tabletop from below, which will also serve for the safe passage of an electric wire.
Step 2. Connecting the current supply wires. From below, under the tabletop, the wires are connected to metal rod-racks: the wire is wound around the lower end of the pin and pressed with a bolt.
The other end of the wires must be connected to a power source, depending on the method chosen. The best connection will be through a plug, which will be connected to the LATER socket. It is possible to connect via self-clamping terminals, as well as by twisting and soldering. It depends on the selected power supply.
In any case, the connection must be made in accordance with the rules for working with electrical installations and devices, be convenient for work and safe during operation.
Step 3. Fixing the Nichrome Spiral. Nichrome spiral is fixed between two racks. A spring is attached to one end of the spiral (there may be two of them).
The spring is needed in order to pull the nichrome thread during operation. The fact is that when heated, the nichrome thread lengthens and sags. The thread in this state will not give a quality cut. Therefore, the thread is fixed in an initially stressed state, so that the spring is slightly stretched.
To fasten the nichrome thread to the pin, washers with an inner diameter slightly larger than the diameter of the pin are used. A small hole is made in the washer for attaching the spiral itself. A small sharpening is also made on the side of the inner diameter so that the washer can be fixed on the thread of the pin.
A spring with a spiral attached to it is inserted into one washer and put on the first pin. The second washer is put on the second pin and a nichrome spiral is threaded into the drilled hole. Next, it is pulled so that the spring is stretched, and fixed.
Step 4: Cutting the Styrofoam To dissolve a sheet of foam into two sheets of a given size, the spiral is set to the desired height. The required distance is measured with a ruler.
The machine is then connected to a power source. The thread heats up and now you can cut the foam, smoothly moving it forward along the countertop.
The cutting speed depends on the temperature of the filament, which in turn depends on the voltage applied and the thickness of the filament itself. Do not try to apply more voltage to achieve high speed, because. this can cause the filament to burn out quickly. Here, a balance between tension, thickness and length of the thread must be selected empirically. The thread should not overheat during operation. When heated, it becomes red or scarlet. But it should not turn white - this indicates that the thread is overheating and that it is desirable to reduce the voltage, otherwise the thread will not last long in this mode. Of course, smooth adjustment is easily done if LATER is available. But if it is not there, then a laboratory power supply can also be made from a computer power supply, the video below has more information. After you have made this foam cutting machine with your own hands, you need to make sure that the machine is safe.
It must be remembered that all activities must comply with safety regulations for working with electrical appliances. The power supply must be grounded, all connections must be carefully insulated. All work on the assembly of the machine must be carried out with de-energized wires. The machine is connected to the mains only while working with foam. After work, it must be immediately turned off. While working with the machine, touching the metal parts and the nichrome thread itself should be avoided.
Step 4: Cut the Styrofoam at an Angle Sometimes it becomes necessary to cut the foam in such a way that one side is higher and the other lower.
To do this, the spiral is set at a slope with the desired parameters. In this way, foam sheets of various sections can be obtained.
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