Among the many types of building materials, foam plastic rightfully occupies a worthy place - a universal tool with special heat-insulating and sound-absorbing properties. The technology for the production of this material involves the use of foamed plastics in the form of frequently located gas cavities. Polyfoam has a fairly low cost, which allows you to purchase it in the amount 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. This article will focus on cutting styrofoam at home.

The main advantages of using foam

It 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 the implementation of repair work in a wide range present ceiling coverings that differ not only in color shade, but also in textured image;
• a unique means of soundproofing, both individual rooms and the entire structure;
• is an environmentally friendly material, since there are no toxic components in its composition;
• is resistant to the effects of various microorganisms, fungi, mold, etc.
• due to the low weight of the product, installation will not be difficult. Transport, handling and stacking are effortless.

Despite all its positive points, working with foam involves observing the nuances of operating this material. Many technical liquids, such as acetone, white spirit, gasoline, etc., have a destructive effect on the foam. An important point is the observance of the temperature regime in the places where this type of insulation is used. When the air temperature exceeds + 500C, there is a likelihood of a destructive process in the internal structure of foam plates and their crumbling.

Varieties of foam

Today, there are several brands of foam, which are indicated by a special marking. PSB-S is a pressless self-extinguishing foam plastic.

A clear understanding 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 and is traditionally used as a heater in places where mechanical stress is not expected. Moisture resistant and fireproof. It is possible to carry out thermal insulation of containers, wagons, attics. This brand is not suitable for shaped cutting of foam;
• PSB-S-25- a universal brand that is a priority. It is widely used for wall insulation both inside and outside. Practical, durable, environmentally friendly;
• PSB-S-35- an insulating agent for foundations or underground communications. Quite often they are used in the process of arranging a pool, playgrounds for sports, lawns. Resistant to moisture, 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 warming floors of ceilings in multi-storey buildings, garages. Moisture resistant, fireproof, durable. Perfect for artistic cutting and use both indoors and outdoors.

The importance of foam density

• The density of any material indicates that the product has a high resistance to various mechanical influences. Polyfoam is no exception. There is a certain pattern - the higher the density index, the more weight the material has. This, in turn, determines the possibility of using foam in certain conditions, since the installation process plays an important role in choosing a material grade.
• The dense foam is able to withstand loads and at the same time provide thermal insulation for the space. Resistance to the appearance of various fungi, mold and other microorganisms makes it possible to use this material in special conditions. The foam strength index has a direct impact on the pricing of this material.
• The low density also suggests 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, lifebuoys, etc.);
• at the stage of repairing refrigerators and other climatic equipment;
• in shipbuilding as an unsinkable vehicle (on large and small ships);
• for the embodiment of design ideas when decorating the interior of the exterior;
• in advertising (volumetric letters).

On sale, foam is presented in the form of sheets of a certain thickness. In the process of fastening it, it is not uncommon for it to be necessary to cut it into smaller segments. The implementation of this task is not such a simple undertaking as it might seem at first glance. Cutting foam has a number of tricks and nuances, the observance of which will allow you to make mechanical processing of the material in a short period of time.

Styrofoam Cutting Tools

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

• a sharp knife with a rubber tip on the tip;
• a soldering iron with a special device - a knife nozzle;
• hacksaw for wood;
• string, etc.

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

• Foam Cutting Knife must be very sharp. It is suitable for working with small dimensions of the material, However, at the end of the cutting object, a rubber nozzle should be located. Before starting the cutting process, it is advisable to fix the workpiece in a vice or another device. The movement of the knife should have a direction "away from oneself", since the possibility of its slipping is not excluded, which in turn can lead to traumatic consequences for the master.

• For the manufacture of parts from foam, where special precision of cutting is required, you can use soldering iron, which is equipped with a special attachment - a knife... During the operation of the soldering iron, the tip 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, as the plastic starts to melt under the influence of high temperatures during the cutting process. As a result, a red-hot drop of plastic mass can get onto the skin or clothing. To avoid this kind of trouble, it is important to secure your movements.
• Common boot knife can cut a sheet of polystyrene up to 40 cm thick. At the same time, the wide blade must be sharpened, and the point must remain dull. The knife must be sharpened every 1.5 - 2 m. Therefore, the sharpener should always be there. Of course, the cutting process will be accompanied by a specific sound - "squeal". But even this can be eliminated by wearing ordinary headphones.
• If you need to cut sheets of polystyrene more than 80 cm thick, then you need to pick up hacksaw for wood with fine teeth... This is very important, since the accuracy and uniformity of cutting depends on the size of the teeth. In this case, you will not have to make any special efforts. At the same time, injuries are minimized. However, this method is relevant if you need to make a long straight cut.
• With a small material thickness, it can be used for cutting regular stationery knife... However, despite the fact that this instrument is quite sharp, it also tends to become dull over time. It would be nice to slightly warm the knife so that the cutting process goes more smoothly.

• Cutting foam with a string- the most popular way at home. The productivity of such a 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 production.
• In some cases, you can even apply grinder for cutting polystyrene... However, the disc should be selected for the minimum thickness of metal. In this case, 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.

Laser cutting of foam

• Cutting polystyrene into segments of the required size is possible not only during thermal insulation work, but also to create special architectural elements of various sizes and configurations. On an industrial scale, laser cutting of foam is used to create volumetric figures, 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 using the shape cutting method, it is important to provide the equipment with the correct software, as well as to automate the process of supplying raw materials to the maximum. According to the sketch stored in the computer memory, you can perform any action of cutting the foam, regardless of the complexity of the project.

• To minimize waste when cutting foam, it is important to accurately calculate everything and complete the layout with maximum accuracy. It is the quality of the initial workpiece that influences the final result. Therefore, the foam sheets must have a perfectly flat surface.
• The sheet of material placed on the machine for shape cutting of foam 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 such 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 the desired element, repeatedly check the conformity of the applied dimensions to the desired format.

Making a device for cutting foam with your own hands

In order to build a foam cutting machine with maximum efficiency, you must have:

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

• Under the influence of the current, 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 styrofoam after the wire is reddish. It is unacceptable to bring excessive incandescence, since the cut will be too wide. Moreover, it should be borne in mind that the heated wire tends to stretch. This indicates the need to use a strong spring in this device.

Precaution! It is important to observe elementary safety rules in the process of cutting polystyrene with the nichrome method, since this material, when heated, emits toxic fumes. Care should be taken to provide a protective mask for the procedure. It is advisable to carry out all work in a well-ventilated room.

Styrofoam cutting video

Machine for cutting polystyrene, expanded polystyrene in 30 minutes.
Making a machine is faster than cutting by hand.

The task was to cut the polystyrene into strips of 6 cm along the entire perimeter of the house.
I decided that making a machine would be faster than cutting with a hacksaw.
And it will be smoother.
For this you will need:

The foundation. I took the door from the furniture (I need narrow strips). You can take a sheet of OSB if you need to cut it in width.
-nichrome wire
-2 bolts
-Washers 4pcs
-nuts 3pcs
-charger for car battery (any with current regulation)

All you need in the photo

We take the door from the furniture (wall in the hall)
it all depends on the task. There was no need for me to cut the entire sheet lengthwise. If there is such a need, then we take a larger base.
We drill holes in two corners and fasten the bolts with nuts.

Nichrome wire can be taken from an old stove or an old iron, or a repair kit for an iron in the form of a nichrome spiral is sold on the household market.
I had a coil of nichrome wire in ceramic insulators. I spent many years in the garage.

We fix one end through a washer simply by twisting.

We fix it on the second end through a washer and a spring.
we take any spring that is not rigid what you find.
It is better if the coils of the spring are thin so that they fit well into the threads of the bolt.
Then it is convenient to rearrange the cut size


Where the washer walks over the bolt with a grinder, we sharpen the inner hole of the washer on one side.
So that it also goes into the thread groove.
it will be convenient to rearrange the cutting height and the size will not go astray.
Otherwise, you will have to figure out how to fix it on some kind of clamp.

Everything!!!
Now we connect to the car battery charger and set 2 - 3 Amperes
Polarity + - no difference.
The current will be small. a strong clamp is not required. You just need to jot down the wires.
How to determine the right amount of amperes?
It all depends on the length of the wire and its diameter.
It will be different for everyone.
The rule is that it should not heat up to red. Otherwise it will quickly burn out.
But about that otherwise it will cut slowly.
You will understand everything during operation.

And we cut
cut
cut

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Polyfoam (extruded polystyrene foam) is used as thermal insulation for external and internal decoration, used for packaging goods or manufacturing prefabricated structures. The material is produced in the form of sheets, which are cut on site and adjusted to the dimensions of the surfaces. For quick cutting of foam, you need a special device that allows you to make a straight or curly cut.

Manual processing of foam is possible at home and small workshops using a simple device assembled from scrap materials. Extruded polystyrene foam has a fairly dense structure, therefore slabs can be cut with a metal tool heated to a certain temperature. As a cutting surface, a wire that supplies an electric current is suitable, with the supply of which the main difficulty of assembly is associated.

A self-made machine makes it possible to obtain tiles or bars of suitable thickness from ordinary foam plastic for packaging, with their further use in various structures. With such a device, you can also cut out foam rubber or similar materials that are needed for the manufacture or repair of upholstered furniture. The compact dimensions of the device for cutting foam 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 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 are sufficient:

1. The base is made of dense plywood, chipboard or solid wood. You can order new parts or use elements of old furniture (doors, walls, shelves). A 400 x 600 mm base is sufficient for working with foam.
2. A string or wire in the form of a thermal knife for foam plastic.
3. Metal studs, screws, springs or regular nails for fixing the wire. The installation height of the cutter depends on the expected thickness of the finished slabs.
4. Mounts for parts on the base. A few self-tapping screws are enough to fix the structural elements.

It will take up to one hour of working time to assemble a thermal cutter. Each of the structural elements can be quickly replaced during the repair process or expanding the capabilities of the device.

Algorithm of actions

To make a device for cutting foam or similar materials, you need the most common tools (hammer, screwdriver, pliers). You can work anywhere with sufficient space (balcony, room, hallway, garage, etc.). No helpers or outside specialists are required.

The 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 a cutting wire

A suitable cutter can be made from nichrome wire (X20H80), which is used in the construction 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 up to 10 mm in diameter is available for making cutting devices.

Precise and smooth threading of the foam is possible when the cutting line is heated to a temperature that is two to three times higher than 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 prevent 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, which are connected to the power source through the captive terminals. AC or DC can be used to cut the material. The power of the source is calculated based on the fact that for effective cutting of 10 mm of wire, up to 2.5 W will be needed (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 Ohm, a current source with a voltage of 12 V with a load current of 12 A. current.

Sources of electricity and connection diagram

Safe cutting is ensured by connecting to a regular household 220 V network through a car transformer. To adjust the voltage in the single primary winding, a knob is provided, with the help of which the graphite wheel is moved and the voltage is removed from the corresponding section. This parameter can be changed in the range from 0 to 240 V. The connection to the power supply is made 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 the common wire. All necessary parameters and wiring 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.

An easier way to apply current to the wire is to use conventional step-down transformers with secondary taps. In this case no need to select the voltage value, 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 configuration of the transformer, providing a certain number of winding turns in the circuit.

You can also heat the wire for cutting the foam using household appliances. In this case, the following nuances are taken into account:

It should be borne in mind that the cutting tool will be hot immediately when energized, so it should not be touched to check the temperature.

To make a thermal knife for polystyrene or foam rubber, it does 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), power must be increased gradually, first connecting low-power current sources. Reliable isolation of the contacts and control of the phase position, which should not be connected to the wire, are of great importance.

Polyfoam is a good heat insulator, characterized by durability and low weight. It is used to create a variety of shapes, blanks and patterns, as an excellent insulation. It is quite simple to work with it. But often such material is produced in the form of blocks with large geometric parameters. Cutting them with a saw or a knife is very inconvenient. Products crumble, which breaks their structure.

The problem with cutting insulating material is solved by a foam cutter, often called a cutter. You can buy it at a hardware store or make it yourself. In the second case, the home craftsman gets at his disposal a tool that suits him in all respects.

Elementary carver - half an hour and ready!

The simplest tool for cutting foam sheets (expanded polystyrene) is made without the slightest difficulty using 4-5 flashlight batteries and a regular guitar string. The process for creating a carver will be as follows:

• batteries are connected in series with each other in one block;
• a guitar string is fixed to the ends of the resulting module.

As a result of these actions, a tool with an electric closed arc is obtained. The current passing through it will heat up the string. At the site of its contact with the material to be cut, the process of melting and cutting of the expanded polystyrene sheet into two parts will be observed.

For the operation of the described homemade thermal knife, the string must be heated to 130–150 ° С. With this simple tool, you can cut 1-3 foam blocks. It is impractical to use it for cutting a large number of sheets due to the fact that the batteries will drain very quickly.

Varieties of electric thermal knives and their features

If the master uses polystyrene regularly and performs large amounts of work, it is advisable for him to make a tool with his own hands that functions from a household electrical network. These homemade thermal knives, which do not require separate chargers, are used to:

• linear cutting;
• true shape cutting.

They use a nichrome thread or a metal plate as a working thermoelement. A mandatory block of such devices is a voltage-reducing transformer (Figure 1). Its windings must meet the following requirements:

• section of cables - from 1.5 mm;
• voltage - from 100 V (primary winding), 15 V (secondary).

Experts recommend connecting the step-down device to an autotransformer (LATR), which allows you to smoothly adjust the output voltage. If you don't want to buy such an expensive device, you can do it differently:

• put a switch on the secondary winding taps;
• equip the step-down transformer with a rheostat.

Linear cutting device - how to make?

Homemade thermal knife for cutting flat sheets of expanded polystyrene foam is a simple design. The principle of its creation will be understood by any craftsman.

The basis of the structure is a frame made of steel profiles or wooden bars. In its lower part, a working surface is mounted made of particle boards, thick plywood. Some craftsmen use sheets of PCB for its construction.

The function of the working surface can also be performed by an ordinary table or workbench. Then there is no need for a frame. And the process of constructing a structure itself is as follows:

• On the table (another flat surface), two vertical supports are mounted, which are fixed with insulators.
• A transformer is connected to the latter through electrical contacts to lower the voltage.
• A nichrome wire is pulled between the insulators. A special load is suspended from it. It is needed to tighten the thread.

The function of such a foam cutter is simple. The electric current passes through the thread, heats it up, which leads to the stretching of the wire. The load does not allow the latter to sag.

The heated nichrome thread easily cuts horizontally a block of foam, which is moved by hand. As a result, flat sheets of insulating material are obtained. Their thickness is determined by the distance separating the stretched wire from the working surface of the table.

When performing the described operation, it is important to ensure the supply of expanded polystyrene at the most uniform rate.

In cases where the material needs to be cut vertically, the cutter design is slightly modified. The frame must be additionally equipped with a holding paw. Hang a nichrome thread and a weight to it, passing the latter through a hole pre-drilled in the table. It is advisable to install a hollow metal pipe in it, which will protect the master from burns when the wire is heated.

Rules for making tools for true shape nesting

If sheets of polystyrene that are large in thickness or geometric dimensions that do not fit on the work surface due to their parameters will be cut at home, it is recommended to make a thermal knife from a hand saw or a hand jigsaw. The work is carried out as follows:

• The cutting blade of the jigsaw (hacksaw) is removed.
• An electrical cable is connected to the tool handle.
• Nichrome wire is bent at a given angle.
• The curly bent thread is installed in the place where the canvas was previously placed, and is fixed with nuts and screws.

All metal elements on a self-made structure are insulated. If you wish, you can immediately bend several nichrome canvases at different angles. Then the curly cutting will be more comfortable.

Heat and soundproof building materials on the market are presented in a wide range, this is foamed polyethylene, mineral and basalt wool and many others. But the most common for insulation and sound insulation is extruded polystyrene foam and polystyrene, due to its high physicochemical properties, ease of installation, low weight and low cost. Polyfoam has a low coefficient of thermal conductivity, a high coefficient of sound absorption, is resistant to water, weak acids, alkalis. Polyfoam is resistant to ambient temperatures, from the lowest possible to 90˚С. Even after dozens of years, the foam does not change its physical and chemical properties. Polyfoam also has sufficient mechanical strength.

Polyfoam also has very important properties, it is fire resistance (when exposed to fire, the foam does not smolder like wood), environmental friendliness (since the foam is made of styrene, even food products can be stored in containers from it). Fungi and bacterial foci do not appear on the foam. Almost ideal material for insulation and sound insulation in the construction and renovation of houses, apartments, garages, and even packaging for storing food.

In building materials stores, polystyrene is sold in the form of plates of different thicknesses and sizes. During repairs, polystyrene sheets of different thicknesses are often needed. With an electric foam cutter, you can always cut sheets of the desired thickness from a thick plate. The machine also allows shaped foam packaging from household appliances to be turned into plates, as in the photo above, and successfully cut through thick sheets of foam rubber for furniture repair.

How easily styrofoam is cut on a homemade machine is clearly demonstrated by a video clip.

If you want to make a cutter for foam and foam rubber, many are stopped by the difficulty of organizing the supply of voltage to heat the nichrome string to the desired temperature. This obstacle is surmountable if you understand the physics of the issue.

Machine design

The basis of the device for cutting the foam was a sheet of chipboard (chipboard). The size of the slab should be taken based on the width of the foam plates that are planned to be cut. I used a furniture door measuring 40 × 60 cm.With this size of the base, it will be possible to cut foam plates up to 50 cm wide.The base can be made from a sheet of plywood, a wide board, fix the cutting string directly on the work table or workbench.

Pulling a nichrome string between two nails is the limit of the home craftsman's laziness, so I implemented a simple design that provides reliable fixation and smooth adjustment of the height of the string during cutting above the surface of the machine base.

The ends of the nichrome wire are attached to the springs, dressed on M4 screws. The screws themselves are screwed into metal racks pressed into the base of the machine. With a base thickness of 18 mm, I selected a metal stand 28 mm long, so that when fully screwed in, the screw does not go beyond the bottom side of the base, and when it is maximally unscrewed, it provides a foam cutting thickness of 50 mm. If you need to cut sheets of foam or foam rubber of greater thickness, then it will be enough to replace the screws with longer ones.

To press the post into the base, first a hole is drilled into it, with a diameter of 0.5 mm less than the outer diameter of the post. In order for the racks to be easily hammered into the base, the sharp edges from the ends were removed on an emery column.

Before tightening the screw into the rack, a groove was made at its head so that the nichrome wire during adjustment could not move arbitrarily, but took the required position.

To make a groove in a screw, you first need to protect its thread from deformation by putting on a plastic tube or wrap it with thick paper. Then clamp the drill in the chuck, turn on the drill and attach a narrow file. The groove will be ready in a minute.

To prevent the nichrome wire from sagging due to elongation during heating, it is fixed to the screws through springs.

The spring from a computer monitor, used to tension the grounding conductors on the CRT, turned out to be suitable. The spring was longer than required, I had to make two of it, for each side of the wire attachment.

After preparing all the fasteners, you can fix the nichrome wire. Since the current is consumed during operation is significant, about 10 A, then for reliable contact of the current supply wire with the nichrome wire, I used the method of fastening by twisting with crimping. The thickness of the copper wire at a current of 10 A must be taken with a cross section of at least 1.45 mm 2. You can choose the cross-section of the wire for connecting nichrome wire from the table. I had at my disposal a wire with a cross section of about 1 mm 2. Therefore, each of the wires had to be made of two with a cross section of 1 mm 2, connected in parallel.

If the electrical parameters of the nichrome wire are not known, then you must first try to connect a low-power electrical appliance, for example a 200 W electric light bulb (about 1 A will flow), then a 1 kW (4.5 A) heater, and so increase the power of the connected devices while the nichrome the torch wire will not reach the desired temperature. Electrical appliances can also be connected in parallel.

The disadvantages of the last scheme for connecting a nichrome spiral include the need to determine the phase for correct connection and low efficiency (efficiency), kilowatts of electricity will be wasted uselessly.