Knife for cutting foam. Cutting foam at home - a knife or a homemade machine? Styrofoam cutter

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:

1. 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.
2. A string or wire in the form of a thermal knife for polystyrene.
3. 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.
4. 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.

A foam cutter is a fairly simple tool that works on the principle of burning material. It can be bought at building supply stores. This is the best option if you have a lot of work to do. In the event that the cutter is needed for 1-2 days, it is easier to make it yourself, since the next time this tool may be needed in many years. But you can also use this option: rent a cutter in one of the construction companies, after calling and finding out if they will provide such an opportunity.

How to make a foam cutter with your own hands?

The easiest way is to make a foam cutter based on a wood burning machine. In the work you will need a nichrome wire, which, when heated, will cut the foam. The manufacturing process of the tool is simple: a spring of a suitable diameter is mounted on a standard metal pin for burning. It should tightly fit this part. A straightened nichrome wire is inserted into the spring. It can be found in any hair dryer. They turn on the device for burning out and when the spring heats up, they start working with the foam.

A 60W soldering iron can also be used to cut this material. You need to choose a tool that uses a plate knife instead of the usual sting. After heating, it will easily cut through foam or any thermofusible synthetic material.

To work with sheet foam, you will need a stable base on which the soldering iron is attached. This will ensure the quality of the cut. As a support, you can use heat-resistant plastic, a piece of plywood or a board. At the bottom of the base you need to make low legs. They are essential in this design.

Closer to one of the sides of the support, a vertical rack of a metal tube is attached. It has two brackets into which the soldering iron is inserted. The longer the bracket web, the farther from the vertical stand the soldering iron is located.
A copper plate is inserted into the cut of its lamellar sting. The edge of the knife is sharpened at a slight angle. The degree of heating of the cutting element is determined empirically. Such a cutter is very convenient for working with both sheet material and curly molding. Note that the width of the cut will be at least twice the thickness of the copper plate. This must be taken into account when performing finishing work.

During construction and finishing work, the question arises of how to cut the foam so that it does not crumble. To do this, use special tools and techniques that are selected based on the size of the foam plate. These cutters can be purchased at the store or you can make your own. To make a tool with your own hands, you do not need special knowledge or skills.

DIY nichrome cutter

Styrofoam is cut with a string heated to +120 ... + 150 ° С and melting the material. Thanks to this, the cut is even, and the foam does not crumble. On such devices, a nichrome thread is installed through which electricity is passed. You can make a simple cutter with your own hands. It differs from the machine in portability and compactness, so the heating temperature of the nichrome wire cannot be adjusted on it.

Necessary tools and materials

To make a cutter with nichrome wire for cutting foam, you will need the following tools and materials:

• a small wooden block;
• screwdriver and drill;
• 2 pencils;
• 2 pieces of copper wire;
• round nose pliers;
• hot glue or PVA;
• insulating tape;
• battery connector;
• switch;
• 1 m wires;
• soldering iron;
• nichrome thread.

The latter is sold in a radio parts store. It can also be taken from old heating elements from a hair dryer, boiler, boiler, etc.

Homemade foam cutter

A homemade cutter is designed for minor work. It is not possible to cut the entire sheet of polystyrene foam with them. To carry out cutting foam at home, you must:

1. Make 2 holes in a wooden block 10-11 cm long. They should match the diameter of the pencils. You need to retreat 1-1.5 cm from the edge. The recess should be slightly deeper than half of the bar in order to fix the pencils. Due to this distance, it is possible to cut a sheet of foam plastic of almost any thickness.
2. Glue both pencils into the holes with hot glue or PVA.
3. In each of the pencils, make a small hole for the copper wire on top.
4. Bend the copper wire with round-nosed pliers so that small rings are formed at its ends. After that, install in the holes in the pencils.
5. Glue the battery connector perpendicular to the wooden block. Additionally, it will play the role of a handle.
6. Stick a switch on the bar so that you can de-energize the string.
7. Then connect 2 wires to the connector. After that, connect to the switch, and then bring each one to a separate pencil. So that the wire does not sag and does not interfere with work, it is fixed with electrical tape. To ensure a reliable connection quality, you need to solder the wires to the connector. The joints must be insulated with heat shrink tubing or electrical tape.
8. Clean the other end of each wire from the braid and screw it to the copper wire. Solder the connection.
9. Thread the nichrome thread into the rings of copper wire and fasten to them. The string should be taut between the pencils. When heated, it stretches and sags a little. The stronger the tension, the less sag.
10. Insert the batteries into the connector and start cutting the foam sheets.

Thus, you can make a simple do-it-yourself foam cutting device. And another version of the manufacture of the machine, see the video:

DIY foam cutting machine

Cutting machines are more convenient because the cutting thread is fixed in them and only the foam needs to be moved. This allows you to increase the accuracy of movements. In the manufacture, you will need the same tools and equipment as in the previous case.

First you need to make a table, which is a wooden base with small legs. The table must be flat and smooth to prevent deformation of the foam. The dimensions of the base are chosen arbitrarily. A bar is screwed perpendicular to the tabletop, and a wooden crossbar is attached to it at an angle of 90 °. Then it is necessary to strengthen the structure with a jumper.

An angular ruler marks the place where the filament will go. If the surface is fairly flat, this can be done with a plumb bob. To do this, a self-tapping screw with a wide head is screwed into the end, and a thread with a load is wound onto it. A hole with a diameter of 6 mm is drilled in the selected place. To prevent the string from burning the wood, a plate of textolite or metal is installed. The material should be placed flush with the surface.

A wire is threaded into the hole, the lower end of which is put on a self-tapping screw. The screw is screwed in next to the hole. The length of the spiral should be such that when heated, the latter becomes red. Since the wire lengthens at high temperatures, a compensating spring must be used to avoid sagging. A spring is mounted on the upper self-tapping screw, and a nichrome thread is attached to it.

An energy source is connected to the ends of the thread, which can be a battery with a voltage of 11.7-12.4 V. To regulate this indicator, a thyristor regulator circuit is used. The regulator can be taken from an electric grinder. You can also control the voltage using a spiral on a polystyrene foam cutting machine.

This spiral is mounted on a wooden block, to which the upper edge of the filament is attached. Connected to the wire in series. Its function is to lengthen the nichrome thread and, accordingly, reduce the voltage. This can be achieved by changing the place of connection to the nichrome spiral. The shorter the distance, the more the thread heats up and the more the foam melts.

If a transformer is connected to the machine, it must be galvanically isolated. In this case, a transformer with taps must be used.

For smooth and even cuts, you need to make a guide rail. It is made from a bar or any other even material.

With the help of such a simple machine, foam cutting is carried out with your own hands. Additionally, you can make different devices. You can make a miter box with your own hands or a tray during the repair, which will help you cut the material evenly at the right angles.

3D foam cutting technology

Expanded polystyrene products have become widely used for marketing and decorative purposes. Company logos are made from expanded polystyrene, names, various figures, decorative elements, etc. are cut out. Therefore, 3D cutting has gained wide popularity. The use of foam allows you to save money and at the same time get a high-quality and durable product.

Volumetric cutting is carried out on special machines. They cut the material using long strings or a laser and allow you to give the foam any shape.

Figured cutting of foam

Figured cutting of expanded polystyrene is carried out on special machines. Some of them are equipped with CNC. When working on the machine, the thickness of the foam sheets does not matter. However, for simple cutting, you can use a simple do-it-yourself cutter.

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.

1. 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.
2. Iron with classic spiral heater. The wire is thicker, suitable for linear cutting. Curly cutting is acceptable, with low requirements for accuracy.
3. 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.

Among the many types of building materials, foam plastic rightfully occupies a worthy place - a universal remedy with special heat-insulating and sound-absorbing properties. The production technology of this material involves the use of foamed plastics in the form of often located gas cavities. Styrofoam has a fairly low cost, which allows you to make its purchases in the quantity that is necessary to complete a particular task. This material is widely used not only as a heat-insulating material, but also in design and advertising, where three-dimensional figures are cut out of it. The article will focus on cutting foam at home.

The main advantages of using foam

This is one of the best materials for thermal insulation of a building, both outside and inside;

• can be used as an additional layer of sealing when transporting any items;
• manufacturers of decorative products for repair work in a wide range represent ceiling coverings that differ not only in color, but also in textured image;
• a unique means of soundproofing, both individual rooms and the entire structure;
• is an environmentally friendly material, since it does not contain toxic components;
• is resistant to various microorganisms, fungi, mold, etc.;
• due to the low weight of the product, installation will not be difficult. Transportation, reloading, as well as laying is carried out without much effort.

Despite all its positive aspects, working with polystyrene provides for compliance with the nuances of operating this material. Many technical liquids, such as acetone, white spirit, gasoline, etc., act destructively on the foam. An important point is the observance of the temperature regime in the places of application of this type of insulation. When the air temperature exceeds +500C, there is a possibility of a destructive process of the internal structure of the foam boards and their crumbling.

Varieties of foam

To date, there are several brands of foam, which is indicated by special markings. PSB-S - bespressovy self-extinguishing foam.

A clear idea and understanding of the meaning of a certain set of numbers and letters will allow you to choose exactly the material that will best meet the requirements of further use:

• PSB-S-15- has a low density index and is traditionally used as a heater in places where no mechanical load is expected. Moisture resistant and fireproof. It is possible to carry out thermal insulation of containers, wagons, mansards. This brand is not suitable for curly cutting foam;
• PSB-S-25- universal brand, which is a priority. Widely used for wall insulation both inside and outside. Practical, durable, environmentally friendly;
• PSB-S-35- an insulating agent for the foundation or communications underground. Quite often used in the process of arranging the pool, sports grounds, lawns. Resistant to moisture, the development of fungi and microorganisms, resistant to mechanical stress;
• PSB-S-50- the density of the material is very high, which indicates the possibility of using it as an option for insulating floors in multi-storey buildings, garages. Moisture resistant, fireproof, durable. Perfect for artistic cutting and use both indoors and outdoors.

The Importance of Styrofoam Density

• The density of any material indicates that the product has a high resistance to various mechanical stresses. Polyfoam is no exception. There is a certain pattern - the higher the density index, the greater the weight of the material. This, in turn, determines the possibility of using foam plastic in certain conditions, since the installation process plays an important role in choosing a material brand.
• Dense foam is able to withstand loads and at the same time provide thermal insulation of the space. Resistance to the appearance of various fungi, mold and other microorganisms makes it possible to use this material in special conditions. The strength index of the foam has a direct impact on the pricing of this material.
• The low density also indicates that when cutting such foam, it will begin to crumble and it will not be possible to make clear shapes with sharp contours from it.

Foam application

This material is widely used not only in construction, but also:

• as a packaging material in medicine;
• as one of the means of ensuring safety in open water (buoys, floats, vest fillers, life buoys, etc.);
• at the stage of repair of refrigerators and other climatic equipment;
• in shipbuilding as an unsinkable means (on large and small ships);
• for the embodiment of design ideas in the design of the interior of the exterior;
• in advertising (volumetric letters).

Styrofoam is commercially available in the form of sheets of a certain thickness. In the process of its fastening, it is often necessary to cut it into smaller segments. The implementation of this task is not as simple as it might seem at first glance. Cutting foam plastic has a number of tricks and nuances, the observance of which will make it possible to machine the material in a short period of time.

Styrofoam cutting tools

Quite often the question arises "what is the best way to cut foam at home." In fact, there are several ways to perform this process. Elements are modeled using the following tools:

• sharp knife with a rubber tip;
• soldering iron with a special tool - a knife attachment;
• wood saw;
• string, etc.

Each method has both disadvantages and advantages. Let's consider them in more detail.

• Styrofoam cutting knife must be very sharp. It is suitable for working with small dimensions of the material, however, a rubber nozzle should be located at the end of the cutting object. Before starting the cutting process, it is desirable to fix the workpiece in a vice or other device. The movement of the knife should have a direction “away from you”, since the possibility of it slipping is not excluded, which in turn can lead to a traumatic consequence for the master.

• For the manufacture of foam parts, where special cutting accuracy is required, you can use soldering iron, which is equipped with a special nozzle - a knife. During the operation of the soldering iron, the nozzle gradually heats up. It remains only to move the device along the surface of the foam with smooth, unhurried movements. However, you should be extremely careful, because during the cutting process, under the action of high temperatures, the plastic begins to melt. As a result, a hot drop of plastic mass can get on the skin or clothing. To avoid such a nuisance, it is important to secure your movements.
• Ordinary shoe knife can cut a sheet of foam up to 40 cm thick. At the same time, a wide blade must be strongly sharpened, and the point must remain blunt. Every 1.5 - 2 m, the knife must be sharpened. Therefore, the grindstone should always be nearby. Of course, the cutting process will be accompanied by a specific sound - a “squeal”. But this can be eliminated by wearing regular headphones.
• If you need to cut foam sheets with a thickness of more than 80 cm, then you need to pick up wood saw with fine teeth. This is very important, since the accuracy and uniformity of the cutting depends on the size of the teeth. In this case, you will not have to make special efforts. At the same time, injuries are minimized. However, this method is relevant if it is necessary to perform a long straight incision.
• With a slight thickness of the material it is possible to use for cutting regular utility knife. However, despite the fact that this tool is quite sharp, it also tends to become dull over time. It would be nice to slightly heat the knife so that the cutting process runs more smoothly.

• Cutting Styrofoam with a String- the most popular way at home. The performance of this process is quite high. However, it is necessary to build a special device, the location of which must be stationary. The accuracy of cutting and the speed of the process is equal to the production ones.
• In some cases, you can even use grinder for cutting foam. However, the disc should be selected for metal of minimum thickness. At the same time, the work is accompanied by noise not only from the foam, but also from the functioning of the tool. And the debris will fly in all directions.

Foam laser cutting

• It is possible to cut foam plastic into segments of the required size not only when carrying out thermal insulation work, but also to create special architectural elements of various sizes and configurations. On an industrial scale, to create three-dimensional figures, laser cutting of foam is used, which functions thanks to special software. Moreover, thanks to the use of a laser, three-dimensional cutting can be performed. As a result, unique figures with a processed inner and outer surface are obtained quite quickly and efficiently.

They are used in the following industries:

• in metallurgy (for casting metal alloys);
• automotive industry (car tuning);
• construction (for the construction of formwork, thermal insulation of buildings and pipes, various architectural forms);
• advertising (logos, etc.);
• theatrical decoration.

This is just a small list of where foam or foam products can be used. For the production of elements by the figured cutting method, it is important to provide equipment with the correct software, as well as to automate the process of supplying raw materials to the maximum. According to the sketch embedded in the computer's memory, you can perform any foam cutting action, regardless of the complexity of the project.

• To minimize waste when cutting foam, it is important to accurately calculate everything and make a layout with maximum accuracy. It is the quality of the initial workpiece that affects the final result. Therefore, foam sheets must have a perfectly flat surface.
• A sheet of material placed on a foam plastic shape cutting machine is fed very slowly and prudently for processing. Therefore, to fulfill the order, it is supposed to involve simultaneously several trained specialists who have the skills to work with similar materials.
• Do not forget about the golden rule "Measure seven times and cut only once." Since the foam crumbles during the cutting process, before cutting out the desired element, repeatedly check that the dimensions applied correspond to the desired format.

Making a do-it-yourself foam cutting device

In order to build an apparatus that cuts foam with maximum efficiency, you must have:

• long knitting needle;
• nichrome wire;
• step-down transformer (12 - 24 Volts);
• rheostat, which can be adjusted if necessary;
• electrical wires.

• Under the influence of current, the nichrome is heated, as a result of which it is possible to cut the foam with ease. In the process of cutting with nichrome, the edges of the cut are sealed, preventing the destruction of the material.
• You can start cutting the foam after the wire has heated up to a reddish state. It is unacceptable to bring excessive heat, as the cut will be too wide. Moreover, it should be noted that the heated wire tends to stretch. This indicates the need for a strong spring in this device.

Precaution! It is important to follow basic safety rules when cutting polystyrene using the nichrome method, since this material emits toxic fumes when heated. Make sure you have a protective mask for the procedure. It is advisable to carry out all work in a room that is well ventilated.

Styrofoam cutting video