Heat gun for soldering with your hands sometimes simply indispensable in the economy. With the help of a heat gun, you can make a number of necessary works in various fields of human activity. It allows you to solder the film, linoleum; soldering chips; turns out to be indispensable for other works.
A heat gun can be useful in circumstances that require changing the structure of the material with hot air.
Currently, there are many models that meet high requirements. Such professional devices are capable of much. However, their cost is significant, and therefore the heat gun for soldering, made with your own hands, for many looks preferable.
Features of heat guns
The heat gun can be attributed to the apparatus for soldering low-melting materials using a heated air jet. In addition to the main function of soldering materials, such an apparatus can be used for heat treatment of the surface of materials with another purpose, for example, for removing paint or heating products, for example, bending pipes.
The device is a typical hot air gun.
The heat gun consists of a housing with high heat resistance, a heating element and a device for forcing air flow. The air in the apparatus heats up to 650-700ºС. To ensure such heating, the power of the heating element should be more than 1.6 kW. An important element of industrial dryers is temperature control, as a rule, speed, 300 and 500ºС. The temperature that is reached on the surface of the materials being soldered is also regulated by the distance from the apparatus nozzle to the workpiece. Most of the thermo guns are adjusted so that when the nozzle is removed by 7-8 cm from the workpiece, the air flow reduces the temperature twice.
Thermohair dryers are widely used to remove old paint from the surface of materials, especially wooden surfaces. In this case, you need the maximum temperature of the air flow, not less than 500ºС. With this warm-up, the paint softens and peels off the wood. Recently, artificial aging of wooden coatings is in demand. Thermal hairdryer perfectly copes with this task at a temperature of 500ºС and removal of the apparatus nozzle 1 cm or more from the surface. Hot air (at the bottom stage of regulation) is used when drying coatings.Back to table of contents
Features of the design of a homemade heat gun
The basic initial requirement for a heat gun for soldering with your own hands can be formulated as follows: the device must create a stream of hot air with a temperature of up to 800 ° C with a heating element power of at least 2.5 kW. In addition, all the details of such a hairdryer should be affordable and affordable. Ordinary household hair dryers are not suitable for this requirement in terms of temperature and power.
The heating coil for the heat gun should not be too long, otherwise it will slowly warm up.
The design, as a rule, can be of two types: stationary and manual. The stationary heat gun is easier to make, since the dimensions of the device are not limited and you do not need to think about the temperature on the handle. However, in this case, the dryer (in this case, as a kind of soldering iron) is fixed motionless, and the part needs to be moved. This circumstance complicates the work. A more promising, albeit more difficult, is a hand-held portable design, which should be small-sized and be able to hold it with unprotected hands.
One of the main problems is the heating element. Heaters in household appliances (hair dryers, soldering iron) are not suitable for power. The necessary heating element will have to be made independently of nichrome wire with a diameter of 0.3-0.7 mm. A wire of larger diameter is able to provide greater power, but at the same time it will be much more difficult to achieve the desired temperature. For compact laying of a heating element from a wire, it will have to be wound in the form of a spiral with a diameter of 5-7 mm.
The spiral of the heating element should be located on a cylindrical base (in the form of a tube or a hollow cone) of a material with high thermal resistance. It is difficult to do without porcelain or quartz elements. Such a base can be removed from inactive household hair dryers, but it is recommended to use a quartz insulator of a tubular halogen lamp for projectors with a power of 2.2-2.5 kW. If you take a blown such a lamp, then this part of a homemade hot air gun can do for free.
Nozzles for the hot air gun.
As a pumping element, a standard compact fan is needed. In the manufacture of a hot air gun with his own hands, this element will cost the most expensive. The supercharger can be taken from any powerful domestic hair dryer. From standard fans, we can recommend the model BAKU8032 with a capacity of 30 l / min. This fan runs on 220 V and has a power of about 400 watts. The simplest and cheapest option that can satisfy the requirements is a small-sized compressor for the aquarium. It must be installed with the receiver, i.e. with air storage. Any small plastic bottle is suitable for this, since there is no heating at the place of its installation, and the flow of hot air is directed in the opposite direction. And the air blower itself is not exposed to thermal effects.
In the design of the body of the heat gun, two options are possible. You can use a material with very high thermal insulation, such as porcelain or ceramics, but this will cause design complexity and a significant increase in price. The second option is the most rational, consisting in reliable thermal insulation of the hot flow distribution channel and the heating element. In this case, the material of the body is not exposed to thermal effects, except for the area adjacent to the apparatus nozzle.
For the tool handle, you can use the case of any old household hairdryer.
As the main part of the body (including the handle), you can use the body from any old large-sized household hair dryer (the older the production year, the better). The body spout, i.e. the nozzle section, must be made of thermally insulating material, which itself can withstand temperatures up to 800 ° C and at the same time insulates the rest of the body from the effects of such a temperature. Directly, the nozzle of the heat gun must be made metallic in order to take into account possible touches to the melt during soldering. Thermal insulation is well provided by quartz elements (plates, tubes), mica, glass or fiberglass, ceramics, porcelain, etc. When assembling the device will need a special heat-resistant adhesive.
In the construction of a self-made heat gun for soldering, it is necessary to provide, firstly, a start switch, and secondly, a mechanism for controlling the power (temperature) of the heating element and the air flow rate. To do this, should be provided smooth regulators - rheostats. The adjustment system can be used from old household appliances if these items are in good condition. As a start switch, you can use the push-button or keyboard mechanism.
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Self assembly hot air gun
The main purpose of the heat gun is the soldering of materials. Materials such as PVC film, linoleum, rubber, are welded by filling the weld with an alloyed filler wire, which is achieved by a stream of hot air. The bundle is melted by heating to 350 ° C. This method is considered basic when connecting linoleum during laying on the floor. Thermofan much easier task of bending plastic pipes, profiles, sheets. Heating during plastic bending is provided within the limits of 300-400ºС at a reduced air flow rate (power). Warming up plastic should be done slowly, gradually.
The device heating element hot air gun.
The manufacture of a heat gun begins with winding a spiral of a heating element. The spiral is wound on a steel wire with a diameter of 5-6 mm with tension. It is better to wind it with wire of nichrome or fehrl with a diameter of 0.4-0.5 mm. The length of the spiral is determined from the condition that its electrical resistance should be 70-90 Ohm.
The spiral is wound on a tubular base from a soldering iron (for example, type EPSN-100) or a halogen lamp for a searchlight. The coils of the helix are superimposed evenly over the area of the cylinder with a gap (touching the coils between them is unacceptable). A layer of fiberglass is wound on top of the laid helix or an asbestos layer is fixed. It is advisable to fasten this layer with heat-resistant adhesive. Then a heat-insulating tube (porcelain, ceramics, quartz glass, etc.) is put on the adhesive layer. The ends of the helix are brought out.
It is desirable to smear the places of withdrawal and the ends of the heating element with heat-resistant glue.
Manufactured heating element is inserted into the internal channel of the housing. Previously, the place of installation must be laid with asbestos, mica or quartz plates, as additional thermal insulation. The leads of the helix, by means of a screw connection, are joined to the power supply wire. This wire must have heat-resistant insulation - fluoroplastic or fibrous insulation. The wire must pass through the starting switch and rheostat to regulate the current supplied to the coil.
In the back of the case, the air blower is mounted strictly coaxially with the channel of the heating element. If the pressure element (compressor) does not fit in the housing, it can be fixed from the outside of the housing to the outside. In this case, an air flow guide tube must be attached to it. This tube must fit the heating element inside the case and be aligned with its channel. Wires for power supply are removed from the supercharger, which are connected to the heater wire so that the switch simultaneously controls the power supply of both elements. A rheostat regulating the flow of air must be introduced into the circuit of the wire for the supercharger - its operation does not depend on the operation of the heater.
The power cord is brought outside to the bottom of the handle of the case, and the button (key) of the switch and the levers of the rheostats are fixed in a convenient place on the outside of the case. Then the halves of the body are combined and interconnected. Set the end element of the insulating material in the form of a cylinder or a cone. The metal nozzle is screwed on. In the design it is advisable to provide a set of nozzles with different diameters of the outlet.Back to table of contents
The principle of the heat gun
Homemade Temofen soldering works as follows. When you press the start button turns on the fan and heater. Hot air in a narrow stream is directed to the desired point. When a sufficient air temperature is reached, the stream melts the solder and flux, and also heats the parts to be soldered. Parts are soldered.
If there is a desire to use a hairdryer as a soldering iron of small parts, for example, microcircuits, then the air flow temperature should be increased to 700-800ºС. Hot air should melt the solder and at the same time heat the metal of the part almost red hot. The air flow should have a narrow look. For such a heat gun, the power of the heating element must be increased to 2.2-2.5 kW. Significantly increases the requirement for thermal resistance of the material of the housing of the apparatus, and the handle at the same time must have a temperature that is comfortable for human hands so that the work does not turn into flour. In a number of designs of hair dryers for ease of use and as an additional thermal protection a rubber coating of the handle is used.Back to table of contents
In the manufacture of a hot air gun for soldering with your own hands you will need the following tool:
- electric drill;
- soldering iron;
Thermofan will help in many cases related to the soldering of small parts, microcircuits. With it, you can weld polymer films, linoleum and do much more useful. The heat gun can be made with your own hands at minimal cost.