Cutting foam: how to process material, nichrome wire and other means, video and photo

The better the cut foam, the less crumbs.

Cutting foam does not seem to be a difficult task, but to do it carefully, you need to have the skill and know some secrets. How and with what to cut foam at home and how to make a machine yourself to simplify this work? Now I'll tell you!

Content

Styrofoam cutting

In the photo - an example of decorative cutting of foam.

The scope of polystyrene foam is very wide. Parts for aircraft modeling are made from this material, it is used in the manufacture of toys and furniture, three-dimensional letters or sculptural elements for advertising are cut out of it, etc. We are interested in a very specific area - construction.

Types of cutting

In construction, foam plastic is used as a heater for roofs, walls, floors, ceilings, foundations and other structures. In the vast majority of cases, thermal insulation consists of expanded polystyrene sheets, which are sold in stores and have standard sizes.

In construction, standard sheets of the same size are used, which are cut on the spot.

During the installation of sheets, they constantly need to be cut, and here the following cutting options are possible:

Longitudinal. This refers to the case when you need to cut a sheet of foam along its plane, for example, into two parts. For example, to make two sheets 25 mm thick from one sheet 50 mm thick: neither a knife nor a hacksaw will help here;
transverse. When it is necessary to cut a piece of the desired shape from a sheet, that is, you will cut perpendicular to the plane of the sheet itself. In this case, you can use a knife, saw and other similar tools;

The foam cutter is well suited for cross cutting in straight lines.

through. Often it is necessary to make holes in the thermal insulation layer for the entry of an electrical cable, pipe or other communications. With some skill, you can get by with a knife, but there are more effective tools that I will talk about;

Smooth through holes can be made using a pipe.

curly. It is used when the edge of the sheet needs to be cut according to a clearly defined pattern with curved lines and a complex profile. Here, a regular knife will not work, and you will need a special tool.

The machine for figured cutting of polyfoam.

Cutting tool

In the photo - a thermal knife for precise cutting of foam.

Styrofoam cutting can be done with a variety of tools. Most popular:

construction knife. During insulation work, a knife is most often used to cut sheets. It can be a construction, stationery or shoe knife. The main thing is that it is well sharpened. The knife is carefully drawn along the cut line, strong pressure is not needed. If the sheet is not cut through, it is broken along the slot;

A construction knife is the most common tool for processing foam.

Hacksaw. For cutting thick sheets, it is convenient to use a hacksaw for metal or wood with a fine tooth. Sold special saws for foam;

It is convenient to cut thick sheets of foam with a saw.

Nichrome wire. A piece of thin nichrome wire is heated by passing an electric current through it. Fixed in a certain way and stretched, a hot string cuts the foam like butter;

A hot nichrome thread is what you can use to cut foam so that it does not crumble.

Thermoknife. In fact, this is a soldering iron, the tip of which is made in the form of a knife blade. The blade heats up and perfectly cuts any plastic, including foam;

A hot thermal knife will qualitatively cut the foam.

Laser ray. Styrofoam can be cut with a laser. This technology is used in the production of sculptural elements or in large-scale production for cutting a wide variety of shapes.

Laser cutting of foam plastic is used mainly in production.

In construction, cutting of even rectilinear shapes is most often required, which the knife can handle quite well. A thermo-knife is ideal in this case.

If you need longitudinal cutting in thickness, a nichrome string is best suited.

How to make a nichrome wire cutter

The machine for longitudinal cutting of sheets on thickness.

How to cut styrofoam in thickness? This question often arises before the builder when it is necessary to dissolve the insulation sheet and make it thinner. For these purposes, a nichrome wire cutter is suitable.

The idea of the machine is quite simple: a string is pulled over a tabletop made of board or plywood, through which a current is passed. The string is set horizontally at the required height, heated by the current and cuts the sheet, which the cutter moves along the tabletop.

Making such a machine with your own hands is quite simple:

Image	Description
	Making a countertop. Choosing a board for the countertop. It can be thick plywood or MDF, a solid board, for example, a cabinet door or a table top.
	We fasten the studs. We fasten threaded steel studs in the corners of our tabletop. To do this, we drill holes and insert anchors into them, which we fix with nuts.
	Heels on the reverse side. On the reverse side of the tabletop we fill the heels from the boards. They are needed so that the ends of the studs do not rest on the floor, and the structure is level. In addition, it will be possible to run wires under the table top.
	First wire. Connect the first wire to the stud. It is better to wrap it around the anchor under the washer, solder and tighten it with a nut.
	Second wire. Similarly, we connect and tighten the second wire with a nut.
	Holes in washers. We take two washers that are freely put on the studs. We drill holes, as shown in the photo.
	Washer sharpening. Opposite the holes along the inner edge of the hole in the washer, we sharpen. This is necessary so that the washer fits exactly into the grooves from the thread and cannot move along the stud.
	Spring. We put the washers on the studs and set the holes inside. We pass the end of the spring into one of them. Any tensile steel spring, such as a clamshell spring, will do.
	Attaching the wire to the spring. We tie a nichrome wire to the free end of the spring and measure the distance to the opposite pin. We leave a margin of 30-40 cm and cut off the excess.
	string tension. We insert a screwdriver into the end of the spring and stretch it. With the second hand, we pass the wire through the hole in the washer and tie it into an interference fit.
	We select a power source. It is best to use a step-down transformer, which gives an output of 6-12 V at a current strength of 6-10 A. Charging for car batteries, a power supply for a computer, a transformer from an old TV are suitable.
	We set the stretched thread in height. To do this, you can use a square, ruler or tape measure.
	We turn on the machine in the network. We connect the supply wires coming from the studs to the outputs of the transformer. We apply voltage to our cutter and wait 10 seconds for the thread to warm up.
	cutting. We take a sheet of foam and lead it along the countertop. The wire will cut off pieces of the thickness we need, which we set earlier, from the sheet. Cutting styrofoam with hot wire produces poisonous smoke. Use a respirator and work in a well-ventilated area.

Conclusion

I think now you understand how and how foam is cut. There are different ways and tools, choose the one that suits your particular case. To better understand the topic, watch the video in this article and ask questions in the comments if you have any.

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