Sometimes you need to process the foam, give it the required form, trim, cut... You can use a knife for this, but it is inconvenient, the cuts are not always even, it is difficult to cut the material, and even the sound is terribly annoying to most people. You can heat the knife, but this is inconvenient as it will constantly cool down. We will make a small and simple cutter for foam plastic and more.
The basis for the foam temperature cutter will be a small wooden block. You can choose any dielectric handle for yourself or carve it, for example, into lathe beautiful and comfortable. The one in the photo also suits me, it is convenient to work with, it has the shape of a rectangular parallelepiped, its length is 13 cm, and its width and height are 1.4 cm.
Our thermal cutter will not exactly cut the foam, but melt it. It is very convenient to give any shape to a piece of foam plastic with such a cutter and you can get the hang of it and make real masterpieces. The heating element is a small piece of metal wire that has a high resistivity; its thickness (diameter) is about 0.6 mm. Examples of such metals and special alloys: tungsten, nichrome, constantine, fechral, chromal. You can buy wire made from such metals, and if you can’t find it on sale, then remove it from an old hair dryer, toaster, or some other simple appliance in which something is heated. A small piece of wire will act as a resistor, which is supplied with a current greater than it should, as a result of which such power is dissipated on it that it heats up.
You will not be able to solder a wire to a high-resistance wire with a regular soldering iron, no matter how hard you try, you can, of course, first transfer some copper to the ends by electrolysis, but we will secure it to a bar with a pair of nails or screws.
You can use many things as a current source, for example, a low-power transformer, a switching power supply. AC voltage from the transformer winding you don’t even need to straighten it with a diode bridge. If there laboratory block power supply, adjust the volts or limit the amps to a value that will provide the desired temperature for melting foam or other similar materials. I often use a 12 Volt power supply - 0.5 Ampere (it gets noticeably hot during long-term use). The wire running from the burner to the energy source must be elastic and withstand constant bending, for example, it can be a specialized acoustic cable. The load will be connected through a small 5.5 x 2.1 mm power socket.
If you want to make a thick tip or, for example, in the shape of a knife, then it will have very little resistance. To heat up such “stings” you need to apply a small voltage value to them, volts, two, three. Transformers with such a miniature output voltage are rare, so if you are rewinding an ordinary one, then we remove the standard secondary winding and take several copper wires fastened in parallel in advance to get a total diameter of about 5 mm, the maximum current depends on it. It is also worth remembering that if the current transformer is designed for low power, then you will not get a large current and voltage out of it. It will be very cheap to buy a power supply unit for fluorescent lamps (electronic transformer) and remake it; there are a lot of instructions on the Internet on how to turn such a thing into a normal UPS.
It turns out that operating temperature The cutter cools down instantly and even after disconnecting from the power supply. Therefore, in order not to waste energy and once again do not overload, we attach a miniature tact button to the gap that gives us voltage. Look permissible current in this button so that it can withstand such a powerful load.
You can give your cutter any shape you like. I ended up with something like a heating saw knife. In this case, a thick wire almost does not heat up due to its low resistance, but a cutting wire, on the contrary, heats up well. If I connect a low-power power supply, then the thread just heats up, and if I take a powerful transformer, then the nichrome thread just gets red hot, it looks cool (it shines very brightly in the dark, just like an incandescent lamp!), but I just don’t need such a high temperature .
Polystyrene foam – light, durable, good thermal insulation material, which is very easy to work with. But it has one unpleasant feature: it is usually made in the form of slabs quite large sizes, which in the process of work have to be cut into smaller pieces. No matter how sharp the knife and saw are, they will not be able to accurately cut the slab, since mechanical action destroys the structure of the foam, causing it to crumble rather than cut. Therefore, you need to use a special foam cutter for cutting.
Foam plastic, like any material, requires cutting, which is why you need a cutter.
The simplest homemade foam cutter
This type of cutter is not difficult to make with your own hands. To do this, just take the thinnest guitar string and 4-5 large batteries for an electric flashlight. Having connected all the batteries in series into a single element, you need to connect a guitar string to its ends and secure it with electrical tape, closing electric arc. Due to the electric current passing through the string, the string will heat up.
Image 1. Diagram of a cutter that allows you to cut flat sheets from a block of foam plastic.
At the point of contact with a string heated to the required temperature, the foam sheet will instantly melt, dividing into two halves, the cut of which will be fused and even. But for normal cutting, the string must be heated to a temperature of at least 120-150º. When working, it will not be difficult to determine whether the string has warmed up enough, since when cutting foam plastic, small stuck pieces will remain on the string. The longer such pieces remain, the lower the temperature of the string. But if they don’t remain on the string at all, then this means that this kind of thermal knife is heated more than necessary.
Such a primitive foam cutter can easily cut 2-3 large layers of material. But with large volumes of work, the batteries run out quickly, so in such cases a cutter powered by electricity is used.
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Options for homemade electric foam cutters
Conventionally, such devices can be divided into groups:
- cutter for linear cutting of foam plastic;
- cutter for figure cutting polystyrene foam;
- cutter with working metal plate.
But despite this division, all cutters have one thing in common.
To make them, you can’t do without a step-down transformer.
Such a transformer must be designed for a power of at least 100 W. Its secondary winding must be designed for a voltage of 15 V and have a winding wire cross-section of at least 1.5 mm.
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Foam Linear Cutting Cutter
Image 2. Diagram of a vertical cutter: 1 – cutting nichrome wire, 2 – weight, 3 – frame, 4 – working surface.
Such devices are mounted from work surface(you can use the surface of a table) with two vertical risers attached to it, two insulators attached to the risers, connected to two contacts connected to a step-down transformer and a nichrome thread stretched between the insulators, as well as a freely hanging load passed through one of the risers (image 1).
This foam cutter works very simply. Passing through a nichrome thread, electricity heats it up, and the suspended weight keeps the thread taut, preventing it from sagging, since when heated it stretches quite strongly. Sometimes, instead of a suspended weight, a spring attached to one of the risers is used to tension the thread.
The heated thread easily cuts the body of the moving foam, turning it into flat sheets, the thickness of which depends only on the distance from the table surface to the tensioned wire. All you need to do is maintain a uniform flow rate of foam across the table surface.
For vertical cutting of layers, a different cutter design is used, in which the cutting wire is stretched vertically (image 2). A frame, preferably welded from metal profile, but one made from wooden blocks (3) is also quite suitable.
The design of the frame provides for the presence of a holder-foot, to which a nichrome wire (1) is suspended using an insulator with a suspended load at the other end (2), passed through a hole drilled in the working surface. Since the nichrome thread will heat up, it is better to make the hole larger and insulate the wooden parts by inserting a metal hollow tube of hollow diameter into it, through the cavity of which the end of the wire with the load is brought out.
This foam cutter will not only easily cut large pieces of foam into blocks required sizes, but will also allow, if necessary, to cut squares, triangles, semicircles and other shaped holes in the material. To do this, just first draw a cutting line along the surface of the foam with a marker.
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Cutter for shaped cutting of foam plastic
If you need to cut sheets of large size or thickness, which due to their size cannot be placed on the desktop, then in such cases use a manual electric cutter, converted from hand jigsaw or a hacksaw in which the cutting blade has been replaced nichrome wire.
Image 3. Diagram of a manual thermal cutter: 1 – nichrome cutting wire, 2 – screw with nut and washer, 3 – textolite handle 4-5 mm thick, 4 – electrical cord.
Such an electric cutter is not difficult to make with your own hands. At the same time, for the convenience of figured cutting, you can make several working tools of different shapes (image 3). The cutting blade of a jigsaw or hacksaw is removed and brought to the handle (3). electrical wire(4). Despite the fact that the voltage will not be too high, it is still better to insulate the handle, like other metal elements, at least using ordinary electrical tape. Instead of a cutting blade, a nichrome wire bent as required is attached to the supplied electrical cable using screws, nuts and washers (4).
As an option, you can also use a wood burning device or a pulse soldering iron to design such a cutter. Such a cutter will be even more convenient, since the electrical wire is initially provided for in the design of these devices. To turn these devices into an electric cutter for foam plastic, it is enough to replace the heating working tools in them with a piece of thick nichrome wire, giving it the desired shape.
Such hand-held cutters are convenient because with their help you can not only cut sheets of foam plastic, but also cut out all sorts of recesses and cavities in them, remove chamfers, in a word, not just cut foam plastic into pieces, but sculpt real works of art from it.
Standard construction has long since sunk into oblivion. This is noticeable when visiting low-rise construction zones. Each home is individual and unique. But every household requires insulation, if it was not provided for during the construction process. It is unlikely that foam manufacturers will produce slabs custom size for small order volumes. You'll have to cut it. But how to cut polystyrene foam when installing thermal insulation for a building with your own hands?
Foamed polystyrene foam can be easily processed by cutting. Before cutting polystyrene foam at home, you need to determine the required accuracy and cleanliness of the cut. After this, select the necessary device for cutting foam from the following:
- saw (hacksaw);
- string;
- thermal cutter;
There is no clear answer to the question: “What is the best way to cut?” as long as there is no certainty regarding the volume and linear dimensions of the parts being processed.
Foam plastic should not be milled due to the extremely low mechanical stability of the material.
Just cutting
When carrying out work on insulating foundations, underground communications, floors under screed, facades under plaster, special precision and evenness of the cut are not very necessary. Moreover, if the building has a simple facade configuration. In this case, you can use hand tool for cutting foam plastic: knife, hacksaw, metal string.
Their use will lead to the loss of granules at the edge of the cut and the formation of a not entirely smooth edge. The presence of a loose fit of the slabs can be leveled by filling the voids with polyurethane foam.
Straight-line cutting with a finely serrated knife is justified with a material thickness of 50 mm; a hacksaw can be used to cut insulation up to 250 mm thick. You can use a serrated kitchen knife to cut foam. Hacksaw with small tooth We buy it at a hardware store.
For ease of use, strings for cutting foam plastic (you can use old strings, for example from a guitar, having a spiral winding) are installed at its ends wooden handles. They cut the insulation with a back and forth motion, as if using a two-handed saw. Large slabs can be cut by two people. In this case, the sheet to be cut must be secured.
Before cutting the foam, the cutting edges must be treated with liquid lubricant. This will create a certain comfort when working (improves gliding, reduces noise).
Curly carving on foam plastic using this tool is extremely difficult.
We use a thermal knife
Cutting polystyrene foam with your own hands using a thermal knife is justified for slab thicknesses up to 50 mm. To cut a piece of polystyrene, a hot knife is advanced with average speed, which ensures cutting quality without tearing out fragments and melting edges.
Purchasing a longer blade for this device is not entirely beneficial. When cutting by hand, it is impossible to cut strictly perpendicular to the surface. The end of the sheet will have a bevel, which is extremely inconvenient during installation. In order to better cut a thick sheet, it is necessary to cut on both sides, deepening the hot knife to half the thickness or a little more.
We make and use a thermal cutter
To cut polystyrene foam with your own hands, devices with a thin hot element are most often used. General principle The actions of any thermal cutter for foam plastic are the same.
The heated element separates the material, followed by sealing of the opened volumes. By using thermal cutters for foam plastic, we obtain a perfectly smooth cut, which is very important for high-quality insulation work.
Purchasing a factory-made foam cutting machine is not economically feasible.
Only if you don’t decide to do this professionally and permanently. In most cases, when cutting out shaped elements is not required, you can use a homemade foam cutter.
Making a foam cutter with your own hands is quite simple and quite inexpensive. After the work is completed, it will not lie like a dead weight and take up space. It can be assembled and disassembled as needed. If there is no need, its components can be used for other purposes.
Before you make a foam cutter, you need to prepare everything you need:
- work surface blank;
- nichrome wire;
- laboratory adjustable transformer (LATR);
Chrome-plated nichrome wire can be used without a step-down transformer, but this increases the risk of electric shock.
- electric wire, fastening for it,
- springs for thread tension;
- adjustment mechanism.
When manufacturing and using the device, follow the rules for the design and operation of electrical installations.
To make equipment for cutting foam plastic, start by marking and trimming the working surface. Determine its geometric dimensions in accordance with the dimensions of the cut slabs. It is better if the table surface is larger than the sheet area.
We install racks (supports) with the possibility of adjustment. To do this, you may need a small device in the form of hexagonal bushings with internal thread. They will make it easier to adjust the cutting height. The cutting wire is tensioned using springs. We lay and fasten the electrical wire on different sides of the thread. We connect the other end of the cable to the LATR (if there is no LATR, it can be replaced by using an autotransformer for charging batteries car). The device is ready for use.
Cutting polystyrene foam at home should be carried out in compliance with safety measures. When heated, toxic smoke is released. Therefore, we cut out parts from foam plastic either outside, or use respiratory protection in a workplace equipped with exhaust ventilation.
Using such a device for cutting foam plastic allows you to speed up the process of preparing insulation fragments as much as possible.
We use automated systems
Delights architectural design also require insulation. In order to preserve their expressiveness, it becomes necessary to manufacture complex elements. How to cut out such details? More affordable option- processing of insulation by milling. But milling of foam plastic is not carried out for the reason that the cutter, when rotating, tears out quite large pieces of material.
Dense polystyrene foam has higher mechanical strength and is easily milled. Anything can be made from it: a letter, a number, a graphic element of any complexity. Even a hedgehog. It is recommended to cut penoplex at high angular speeds with an average linear feed. To install the manufactured fragments on the façade, ceresite is used.
Laser cutting polystyrene foam is the most advanced technology, combining hot cutting tool and accuracy automated system. Laser cutting of foam plastic allows us to produce parts of any complexity with the highest precision with a minimum level of waste. Laser cutting of foam plastic ensures absolutely smooth surface cutting using a hot beam of directional light moving at high speed. There are no restrictions on the thickness of the material and the complexity of the element.
The choice of cutting equipment used for foam boards and extruded polystyrene foam must be conscious. Meet technological requirements for finished products and be economically feasible.
Polystyrene foam is durable, lightweight and very good thermal insulation material. It is very easy to work with it. But there are some nuances in working with this material.
Since it is made in the form of large slabs, it is very often necessary to resort to cutting them. This can be done using and regular knife, but no matter how carefully they try to do it, they will not succeed.
And all because mechanical impact will disrupt the structure of the foam. That is why experts recommend using only a cutter or, as it is also called, a foam cutter for such actions.
You can, of course, buy such a multifunctional tool, but if you make it yourself, you can adapt it to your needs and, of course, save money.
If you plan to work with the cutter in industrial purposes, then it is still better to buy an electrical device that will be designed for large and frequent loads.
How to do it yourself
The need for a cutter can arise at any time if you do some household chores quite often. Perhaps someone has encountered the need to make a part using a special mold for casting with epoxy resin.
And to do this, you will need a piece of foam. For example, you can use foam from TV packaging. It is necessary to draw on it using a ruler, compass and ballpoint pen places where holes will need to be made in the future.
This is where the need for an electric cutter comes into play. After all, fulfill given action without ruining the foam sheet, it will be difficult without such a tool. Let's consider one of the options for how to make a device of this type at home.
A homemade cutting device can be various designs. It is on it and the type of cutting that will depend on how exactly the cutter copes with its goals.
Kinds
Before you start making a cutter, you should decide for what purpose you need it, because depending on the purposes, they are divided into several groups:
- with metal work plate;
- for linear cutting;
- for shape cutting.
Stages of creation
Since linear cutting is the most common, let's look at this option in more detail:
- Cutting part. To do this you will need nichrome wire, approximately a spiral with a diameter of 0.6 mm. It can be taken from old electric stoves or other heating electrical appliances. The length of such a wire should be 14 cm (its resistance will be 2 ohms).
- Transformer application. For everything to be correct, the first step is to calculate the voltage and current for heating the cutting part. This can be done using the formula - Ohm's law I=U/R. Thus, you can determine the power of the power transformer.
- Making a cutter. The base can be made of any metal, but its length must be at least 11 cm. Next, an insulator - a PCB plate - must be attached to the end. Now fasten the contact groups along the edges of the plate; they can be removed from the electrical outlet. It is into these contacts that it will be possible to attach spirals of different shapes.
- How does the cutter work? After the cutter is plugged in, the wire will heat up and become slightly reddish in color. This is exactly what matters, since a heated cutter will make it possible to easily and quickly cut the foam, which will not peel off.
It is important to know: Having received such a device, in just three minutes it will be possible to cut the required shape from a sheet of foam plastic.
Be sure to follow all safety rules so as not to injure yourself and others. After all, the power of the cutter is enough to damage any part of the body during operation. And connecting to electricity further increases the risk of injury.
Step-by-step production of a thermal cutter
You can make a thermal cutter using a burner or soldering iron and an old jigsaw. Let's consider the manufacture of such a device step by step:
- Sleeve. Initially, you need to make the main and most difficult thing - the bushing. So, to do this, the plate must be bent and turned. Next, you need to make a hole in the sleeve; the thread will be inserted there in the future.
- Burner. You need to cut off the wire that leads to the hole, take suitable connectors, and then solder them to the break point.
Note: Such areas must be isolated.
- After everything is done, you can connect the thermal cutter. Cut an old jigsaw in half. A pre-prepared claw plate must be attached to the upper part with screws. But we attach the bottom to the base using self-tapping screws.
- Insert the sleeve into the foot. Now with special attention From the hole you need to use a plumb line or a square to mark a point under the hole of the sleeve. Next, drill a hole in the base. The diameter of the hole in the base should be about 5 mm.
- Thermal cutting machine So, when everything is ready, you need to straighten the nichrome wire. To do this, you should turn on the burner at full power and touch the nichrome with the wires from it. Everything must be done in such a way that there is a distance between the wires equal to the height of the device. If the thread does not heat up, but the burner begins to hum, find a thinner wire. This is necessary because the one you selected does not have enough resistance.
Take note: nichrome should be hot, but should not get red hot. If the string turns red, you need to reduce its heating using the regulator. In the event that the nichrome is red even at a minimum, then a compensator should be left 5-10-15 cm above the spring of nichrome wire. And only after that you can make contact.
- Operation of the device. With a pre-installed guide, you need to cut foam dies to a given thickness, or you can make the shape curly.
Application
If you are making repairs or doing wood cutting, or you need to cut a piece of plywood, then an electric cutter will be very useful for you, which can also be used even for cutting thick fabric.
If you think that for all of the above actions you will only need to use a thermal knife, or a hacksaw will suffice, then you are mistaken.
After all, a hacksaw will not make the edges smooth and not torn, as is the case with a cutter.
During construction and finishing works The question arises of how to cut foam plastic so that it does not crumble. To do this, special tools and techniques are used, which are selected based on the size of the foam board. These cutters can be purchased at a store or made independently. To make an instrument with your own hands, you do not need special knowledge or skills.
DIY nichrome cutter
The foam is cut with a string heated to +120…+150°C and melts the material. Thanks to this, the cut is even and the foam does not crumble. Such devices are equipped with a nichrome thread through which electricity is passed. You can make a simple cutter with your own hands. It differs from the machine in its portability and compactness, so the heating temperature of the nichrome wire cannot be adjusted on it.
Required tools and materials
To make a cutter with nichrome wire for cutting foam, you will need the following tools and materials:
- small wooden block;
- screwdriver and drill;
- 2 pencils;
- 2 segments copper wire;
- round nose pliers;
- hot melt glue or PVA;
- insulating tape;
- battery connector;
- switch;
- 1 m wires;
- soldering iron;
- nichrome thread.
The latter is sold in a radio parts store. You can also take it 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 an entire sheet of polystyrene foam with it. To cut foam plastic at home, you must:
- IN wooden block make 2 holes 10-11 cm long. They should match the diameter of the pencils. You need to step back 1-1.5 cm from the edge. The recess should be slightly deeper than half the block to fix the pencils. Thanks to this distance, you can cut a sheet of foam plastic of almost any thickness.
- Glue both pencils into the holes using hot glue or PVA.
- Make a small hole in the top of each pencil for the copper wire.
- Bend the copper wire with pliers so that small rings are formed at its ends. After this, install it into the holes in the pencils.
- Glue the battery connector perpendicular to the wooden block. Additionally, it will act as a handle.
- Glue a switch onto the block so that you can turn off the power to the string.
- Then connect 2 wires to the connector. After this, connect to the switch, and then output each to a separate pencil. To prevent the wire from sagging and interfering with work, it is fixed with electrical tape. To ensure reliable connection quality, you need to solder the wires to the connector. The joints must be insulated using heat shrink tubing or electrical tape.
- Remove the braid from the second end of each wire and screw it to the copper wire. Solder the connection.
- Thread the nichrome thread into rings of copper wire and secure to them. The string should be pulled tight between the pencils. When heated, it stretches and sags a little. The stronger the tension, the less sagging.
- Insert batteries into the connector and start cutting foam sheets.
This way you can make a simple device for cutting foam plastic with your own hands. And another option for manufacturing the machine, see the video:
Do-it-yourself foam cutting machine
Cutting machines are more convenient because the cutting thread is fixed in them and only the foam plastic needs to be moved. This allows for increased precision of movements. During manufacture you will need the same tools and equipment as in the previous case.
First you need to make a table that represents wooden base with small legs. The table must be level and smooth to prevent deformation of the foam. The dimensions of the base are chosen arbitrarily. A block 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 using a plumb line. 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 location. To prevent the string from burning the wood, a plate made 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 it turns red. Since when high temperatures the wire lengthens, it is necessary to use a compensating spring to avoid sagging. A spring is attached to the top 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 electric grinder. You can also control the tension 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. Connects to the wire in series. Its function is to lengthen the nichrome thread and, accordingly, reduce tension. This can be achieved by changing the connection location 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 block or any other smooth material.
With the help of such a simple machine, you can cut foam plastic with your own hands. Additionally you can do various devices. During repairs, you can make a miter box with your own hands or a tray that will help you cut the material evenly at the desired angles.
3D foam cutting technology
Expanded polystyrene products have become widely used in marketing and decorative purposes. Company logos are made from polystyrene foam, names, various figures, decorative elements, etc. are cut out. Therefore, 3D cutting has gained wide popularity. Using polystyrene 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.
Shaped cutting of foam plastic
Figure cutting of polystyrene foam 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 DIY cutter.
