How to cut styrofoam - maximum results with minimum waste. How are polystyrene slabs cut? How to cut styrofoam at home
Those who are planning to insulate an apartment or a newly-built house with their own hands should definitely familiarize themselves with the ways in which styrofoam is cut at home, because this is one of the most popular and affordable methods of insulation.
Styrofoam is a foamed material and is mostly air, so it is very lightweight and easy to work with. However, you should not think that no problems arise, because in addition to everything, polystyrene and a rather fragile material. Therefore, if you use an electric grinder, then you should not rely on even edges, besides, the entire room and site will be strewn with crumbled foam.
No matter how sharp the knife is, the material will still crumble. Of course, this is a minor defect and the sheets will be usable, but cleaning will turn into a troublesome event.... There is a way out of this situation, you can use a thermal knife. In this case, the edges of the material are melted and it does not crumble. But bad luck, such a device costs a lot, but in principle, you can heat up an ordinary knife. However, in this case, one must be very careful not to get burned, and the work will be significantly delayed.
For this purpose, you can use a different cutting tool, for example, a grinder, only then you should use the thinnest disc. Very often builders also use a simple sharp knife. Sometimes it is advised to take a hacksaw with very fine teeth, but the latter method is very dubious. In addition, the stores sell special thermal knives designed for working with foam.
The thermal knife heats up to 600 ° C in just 10 seconds. However, this tool is quite expensive, so it does not always make sense to buy it.
The way out of the situation in many cases will be a device for cutting foam sheets, made by yourself. It is probably somewhat cumbersome, but with the necessary components, it is absolutely free and always available. And if you have to do large-scale work, for example, you have ahead of you, which you built for your large family, then the question of how conveniently to cut the foam plastic, and even a lot and quickly, will not come up throughout the event, no matter how long it lasts.
In order to assemble a foam cutter, you will need a tabletop, each with a pair of springs, M4 screws and 28 mm long struts, as well as a nichrome thread, which will act as a cutting tool. First, we make two holes at the base, press the racks into them, and at the base of the screw head we cut a small groove, thanks to which the thread will be securely fixed in a given position.
When everything is assembled, we attach the string to the screws, but since it can sag during heating, it should be connected through springs, then the thread will always be in a taut position. The power source is connected to such a device by means of ordinary twists. So you can make a homemade and very effective foam cutter, while spending a minimum of effort, time and money.
Trying to cut the foam yourself
Now let's talk a little about different technologies, methods and, of course, we give detailed instructions what and how to do.
How to cut polystyrene yourself - a step-by-step scheme
Step 1: preparatory work
It doesn't matter what kind of tool you are going to use - a knife, nichrome thread or other cutting devices, you still need to start with the marking. So we take a ruler, square, tape measure, pencil and put marks on the surface of the sheet, then connect them in lines. In general, we draw the outlines of the future cut.
There are more ways you can. For example, using nichrome thread. In this case, a small current is supplied to it, which is capable of heating the string to the required temperature, and the cutting is accurately performed along a given contour. Of course, the quality of the cut in this case will be much better, but you will have to work a little to make the machine. Therefore, this method is not always justified if you need to process only a few sheets, there is simply no point in wasting time designing the fixture. As you can see, it is impossible to give an unambiguous answer, what is the best way to cut polystyrene, it all depends on the volume and skills.
How is it easier to cut styrofoam?
Heat-insulating structures are assembled from modern expanded polystyrene, decorative elements are cut out and a large number of other things are produced.
Its scope is very wide. And not least due to the fact that this material is easy to process, it fits quickly and you can cut it with your own hands.
Homemade thermal cutter for expanded polystyrene
However, you also need to be able to cut styrofoam with your own hands. After all, in order to get a really high-quality cut and the final detail, you need to try hard. Note that the foam is not dangerous for human health.
1 Cutting Styrofoam
So, expanded polystyrene, like any other material, needs to be processed before use. Initially it is delivered to conventional slabs with a certain thickness. However, the shape of the plates is not always enough to be used wherever necessary.
Often the slab has to be cut into pieces, trimmed, cleaned up. Sometimes it becomes necessary to cut the decorative part at the edge of the slab or to make a certain corner.
There are actually a lot of options. But the question remains one. How to cut styrofoam? It would seem, why else invent any additional units, buy a special cutter for foam, if it’s not something to cut, you can even break it with your own hands. And this is literally.
Here it is necessary to turn to the features of the expanded polystyrene itself and reinforced foam for the facade. The foam itself consists of small polystyrene balls.
The initial raw material in it is a polymer that is mixed with foam fillers and air. The result is a rather pliable and very light construction that can be easily cut or broken by hand.
But breaking foam is not the best solution... The break line will never be accurate. The styrofoam balls will bend it, making the final structure unsuitable for precision work.
However, we still note that it is very easy to break or cut the foam. That is, cutting foam at home is quite real. Another question is how to do this accurately and with minimal damage to the material. This is where a foam cutter or any home-made apparatus will come in handy.
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2 Cutting tools
Styrofoam cutting tools come in different designs. It depends on the design and type of cutting how exactly the foam cutter will cope with its tasks.
Expanded polystyrene consists of small balls and can crumble
A mechanical cutter is used in order to be able to carry out relatively small jobs in confined spaces. It is possible to cut the body of expanded polystyrene with a device of mechanical action. But the quality of the cut, which will turn out in the end, may not be the same as we would like.
The thermal foam cutter is already a professional equipment. It is used by builders, designers and other similar professionals.
The thermal cutter will quickly punch holes or cut lines in any type of Styrofoam. From conventional to high density extruded foam.
The thermal apparatus basically uses a red-hot thread or wire.
By the type of assembly, the apparatus for cutting polystyrene foam for insulation of a house with foam from the inside can be divided into:
- Brand samples;
- Homemade samples.
In the first case, we are dealing with units that were created at the factory. They were specially designed and conceived so as to give a person maximum productivity and convenience during work.
Branded models include both specialized knives for foam plastic and large thermo cutters or other professional equipment.
For example, the same laser cutting of foam is only possible through the use of low power factory lasers, which are controlled by a computer. They are expensive, bulky and quite complex, but the result of working with them you will get almost perfect cutting.
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2.1 Mechanical cutting
Mechanical cutting is performed with tools that basically use the force of mechanical action or friction.
Most often, such equipment is used at home. When you do not have the opportunity to buy a thermal cutter, and there is no desire. Let's not forget that a high-quality thermal cutter can be quite expensive.
And it is far from always worth buying, especially if you just need to cut a couple of expanded polystyrene plates for thermal insulation with your own hands.
Styrofoam can be cut even with an ordinary blade
The easiest way to cut the foam is to take a regular knife, especially if the foam is cut for insulation sewer pipes in the ground. A utility knife with a medium blade is ideal. With its help, you can easily cut a slab with a thickness of up to 6-8 cm. Moreover, the slab will be cut efficiently, especially if you already have at least basic experience.
But grinders and jigsaws, if they can be used, then very carefully. Here it is already necessary to understand that a strong torque is too seriously affecting the weak structure of polystyrene foam. If you don't guess with the torque and the choice of the disc, then you can ruin the stove with your own hands.
Recommendations here can only be general. It is advisable to buy special equipment for cutting foam. If you don't have anything like that at hand, then try to at least find the thinnest disc for a grinder or a jigsaw blade. The thinner it is, the better.
In general, you need to be careful with saws. It is better not to use a regular saw for styrofoam. Unless you need cutting precision at all. But in this case, it is easier to just break it.
If you buy a special saw, then there is already another conversation. But in any case, you need to be very careful, since the saw, due to the unevenness of the efforts, has more chances to thoroughly damage the material.
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2.2 Thermal cutting
For thermal cutting, a thermal cutter is always used. The thermo cutter is a special unit for cutting polystyrene foam, it costs almost the same as the foam adhesive.
It consists of only a few parts. The main part is a working transformer that supplies voltage. The transformer can have batteries or can be powered directly from the mains. It all depends on the specific model.
From the mini-transformer there are two arcs or fasteners. These arcs are essentially the body of the work item. A special thread is tied to each end of the arc. Nichrome is most often used. The thread is stretched between the ends of the arc so as to form a tightly taut wire.
When the transformer is turned on, it supplies electricity to the arcs, and they, in turn, heat up the thread itself.
The hot filament cuts through the foam without any problems in any position and any size. After all, the polymer is extremely unstable, and it interacts very poorly with high temperatures.
Special stand for a homemade foam cutter
The big plus of the thermal cutter is that it gives you the ability to work with filigree precision. More precisely, cutting can only be carried out with lasers. And even then, if we exclude the human factor.
Nichrome, heated to a serious temperature, cuts the foam like a knife hot oil. Moreover, he does not even touch the stove properly, that is, you will not have to apply any physical pressure. Why is it convenient? Because applying physical effort is always fraught with the possibility of making a mistake.
If all the work is done by a heated wire, which rather melts the foam than cuts it, then the chance of making a mistake becomes minimal.
2.3 Homemade thermal cutter
Smart radio technicians have probably already thought that the design of the thermo-cutter is very simple, which means that it can be assembled with your own hands. Indeed, you can assemble a thermal cutter without any problems.
Your main task will be to select a small transformer for cutting Rockwool insulating cylinders and similar products. Well this is actually not such a problem. You can take a transformer from a TV or convert it from a working sample.
Next, you need to collect an analogue of the arcs. The simplest such mechanism is to mount on wooden plank two long screws. The tree will not allow them to conduct electricity, between themselves, so the only conductor will be a stretched nichrome thread.
The thread is pulled between the screw heads. Then all that remains is to connect the transformer to the screws, then turn on the electricity and adjust the voltage.
It is advisable not to overdo it with stress and clearly understand that there is a certain correlation between the thickness of the nichrome thread and the operating voltage at the output.
Too high voltage will make the thread red-hot, and in this position it will simply burn out the expanded polystyrene without even touching it. As a result, you will not be able to cut evenly.
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During repairs, especially those related to redevelopment or insulation, a material such as polystyrene is often used. Its popularity is due to the fact that it is quite cheap and has good insulating properties. But many people have a question, like polystyrene, and not only quickly, but also efficiently. So that the cut line is even, and the edges are not "shaggy".
Polyfoam, as you know, is hard (hard) and soft. Solid is well processed, and for this reason, by the way, it is popular with fishing enthusiasts - they make floats out of it. But the soft one usually crumbles. The thickness of sheets (pieces) also varies, so there is no single recommendation for cutting foam. But you can still give some advice.
If the foam is soft, it can be cut into pieces with a paper cutter. It cuts styrofoam like butter. However, it should be taken into account that the blade of such a knife is rather flexible, so if the piece is "thick" enough, then it will hardly be possible to maintain a straight line. And if it does work out, then the cut may not be vertical, but with a bevel.
Harder and thicker foam sheets can be cut:
- sharply honed. If the thickness of the sample is not very large, then it is better to heat the knife and then cut it. Cutting will go much faster;
- a hacksaw for metal;
- saw for wood with fine teeth.
Those people who have tried to cut foam with a jigsaw do not recommend using this tool. It is not possible to make the cut even.
Most best method- cutting foam with nichrome wire. For this, a rather primitive "machine" is assembled. The wire is stretched vertically, and current is passed through it from a 12V transformer. "Craftsmen" often adapt power transformers from old TVs for these purposes. A rheostat or variable resistance must be included in the electrical circuit. Calculating it for a person familiar with the basics of electrical engineering will not be difficult.
Regulation of the amperage is necessary so that the wire does not get too hot. Excessive heating of it will lead to the fact that the foam will begin to melt, and nodules are formed at its edges along the entire cut line, which cannot be removed "evenly". This method is attractive in that it allows you to cut out neat fragments not only in a straight line, but also along convolutions, kinks. This essentially makes slicing versatile.
You can try with a grinder. However, choose the thinnest disc. But when using such a tool, it will not be possible to get a high cut quality, this will give the same result as when using a jigsaw. Someone advises using a soldering iron with a specially prepared thin tip.
All of these methods are good in their own way. Therefore, you need to choose according to the circumstances, taking into account all the features of such cutting.
When carrying out work related to the insulation of the house, better material than Styrofoam you won't find. It is popular because it is inexpensive and is a pretty good heat insulator. But when you got down to work, the natural question arises of how to cut the foam and make the parts you need from it, so that the cutting lines are even and have the configuration you need.
There are two types of foam: hard, or it is also called tough, and soft. It is easier to machine (cut) the hard type of foam, therefore it is more popular. Soft types of foam crumble, and a special regime must be applied to them. There is also no uniform thickness of foam sheets, and from this it follows that cutting modes will be different and require an individual approach for each case. The soft look can be cut with any sharp thin object, even a credit card. Place a ruler or flat bar along the cut line and trace along the line with your cutting tool. Then move the foam board so that the cut coincides with the edge of the table, and while pressing the part of the board that is on the table, lightly press on the sagging one. The foam will break along the cut line. You can use a serrated knife from your kitchen kit to cut the styrofoam. To make it more convenient to work, it must be rubbed with a wax or stearic candle. If you need to keep the styrofoam clean, then use a stearin candle white... Cut the foam with even long strokes so that the knife sinks with the entire blade. A retractable paper cutter is a good choice for cutting thin sheets of foam. Various parts and fragments can be cut with this knife. First, make an incision not to the full depth, and then cut off the part you need with even movements. Make sure that the blade of your knife is constantly sharp, because if it is dull, then you will not be able to make an even cut.
We have listed all the main ways to cut foam, they are all good in their own way. Choose for yourself what suits you best.
Polyfoam or expanded polystyrene refers to a versatile material that is used for insulation and sound insulation in building structures... Its structure is based on foamed plastic. This explains why foam crumbles quite often when cutting.
When processing the material, it is necessary to decide how it needs to be cut so that the cut line is even, and the crumbs are as small as possible.
Tool types
Foam cutting is carried out using mechanical and thermal types of tools. Novice craftsmen, especially with small cutting volumes, are recommended to use a mechanical tool.
Mechanical cutting ... The most common tools at hand include a knife, jigsaw, saw and grinder.
Ordinary knife
... The main focus when choosing a knife is on its blade. If it is sharp, the cutting process is faster and less waste is generated. The knife must be preheated before cutting.
The disadvantage of this method is that the use of a knife is possible with a foam thickness of 1 - 5 cm.
Boot knife ... Typically, this knife is initially quite sharp. Therefore, its blade passes through the cellular foam structure relatively easily.
Disadvantages to use:
- the ability to cut only thin sheets;
- the knife blade dulls quickly;
- the need to have a whetstone available.
Stationery knife ... The stationery version of the knife is best used for soft material. This knife has thin and flexible blades, so it is not used for cutting thick slabs.
Advantages:
- little rubbish;
- availability of purchase;
- low cost.
The stationery knife has a set of interchangeable blades. Dull blades break off and are wasted.
It is recommended to heat the blade before direct use. Then the plastic capsules will melt, and much less crumbs will be formed.
Jigsaw trimming is used when cutting foam up to 10 cm in thickness. This method does not require a lot of effort. 
Flaws:
- the cut is not perfectly flat;
- a sufficient amount of crumbs is formed;
- cannot be used in the absence of power supply
Hand saw for wood
... If the thickness of the foam reaches 40 mm, then it is better to cut it with a hacksaw on wood. The method is quite simple and quick, without much physical effort.
A saw with fine teeth is better suited. This tool is used only for making straight cuts.
"Bulgarian" ... The advantages of the grinder are that it cuts the foam itself, if you use the thinnest circles.
However, it is not recommended to cut thick material with a grinder. You will not get a high-quality result, but there will be a lot of garbage.
In addition, this option is not very good because of the squeal that occurs when the foam interacts with the circle of the machine. Plus, the noise of the instrument's engine is added to it. Therefore, in the case of cutting a large number foam boards, you should put on headphones from the very beginning of work. Add to this list the electricity consumption that will need to be paid.
Nichrome wire cutter ... The practice of working with foam shows that a high-quality cut is formed when using a tool with a heated wire. The edges are even, smooth, and there are practically no crumbs. The advantages of the method include high cutting speed and productivity in volumes similar to industrial ones.
The active use of the method is hindered by the difficulty of purchasing it due to the lack of it in stores. With an urgent need for a machine, there is only one way out - to make a cutter yourself. This is a separate question, which is devoted to many good articles on the Internet containing step by step instructions and illustrations.
Easy way to cut
Cutting can be done with thin steel wire. It should be fixed on wooden handles... They are placed at different ends of the cutting surface. Sawing resembles the process of sawing wood. You will need an assistant who will take one of the pens. From friction, the string heats up, so the cutting line turns out to be even and smooth.
Observe the safety rules, given that when heated, the formation and release of substances harmful to the body occurs. Work should be done in a well-ventilated area or outdoors.
Outcome
From the review, we can make a general conclusion that the process of cutting foam is quite simple and fast. The processing method is selected depending on the selected tool, the amount of work, the shape (straight, winding or volumetric) in which the result should be obtained.