Do-it-yourself heat gun (gas, gasoline, electric): an easy way

Heating

Author Anton

Date
Jan 25, 2016
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Owners of garages, production facilities, warehouses and other similar premises are faced with the problem of heating the air space, or rather, the complete absence of it. In such cases, it is necessary to stock up on an auxiliary source of heating the room. A heat gun copes with such tasks without any complaints. It is used for heating garages or storage rooms and as a dehumidifier for basement rooms or mine wells that are constantly collecting moisture in the autumn-spring period. The heat gun found a secondary application in the construction and agricultural sectors. Such a device will dry painted walls and putty in a short time, and at the same time it will easily achieve and continue to maintain the desired temperature level on the farm or in the granary.

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You can easily make such a device yourself

How to make an electric heat gun
Principle of operation
Stages of making an electric heat gun with your own hands
How to make a heat gun using diesel fuel
Stages of making a diesel heat gun with your own hands
How to make a gas heat gun
Stages of making a gas heat gun with your own hands

Thus, a heat gun is a unit with a built-in fan inside the housing, which supplies a hot air stream. Heating of the flow occurs when heating elements installed in front of the fan are heated. The name “cannon” comes from its similar appearance to the military weapon of the same name.

Depending on the power the heat gun is designed for, household appliances and industrial heaters are distinguished. In turn, according to the type of power supply, these devices are classified into the following types:

Heat gun powered by electric current.
Diesel fuel heat gun.
Gas heater.
Multi-fuel heat gun.
Infrared or air gun.
Heat gun with water device.

Each type of heat gun listed has a number of individual features. In specialized stores, such devices are sold ready-made, but the price range for them is not very attractive. Thus, a home-made heat gun will cost several times less. In order to make a gun of one type or another, it is necessary to have certain knowledge about the operating principles of specific heating elements built into the device.

How to make an electric heat gun

This is one of the most common types of portable thermal heaters. This popularity is due, first of all, to the simplicity of the internal structure of the device, as well as mobility and dimensions. The cost of such equipment varies depending on the specific power output. Therefore, a self-made electric heat gun will not cause much damage to the budget, but in the end you will end up with a unique heater. It can be used for heating small spaces and other household purposes.

Due to the fact that the device operating from the network is called an electric gun, it is necessary to have at least basic knowledge of the operation of electrical equipment. A heat gun of this type has the following unique differences:

It operates without an open flame, therefore, the risk of a fire hazard is minimized.
Mains-powered guns have sufficient power reserves, which allows you to heat up a room in a matter of minutes.
Any problems during the operation of the device are electrical related, therefore, do-it-yourself repairs are easy and simple.

Calculation of device power

In order for the gun to be as effective as possible in your room, you first need to calculate the minimum power of the device using the formula.

Qt=V×∆T×K/860, where

Qt - minimum power of the heating device in kW/hour;
V is the volume of the heated room in m3;
∆T is the difference between the minimum outdoor temperature and the required indoor temperature in °C;
K - heat loss coefficient: 3.0 - 4.0, if the building is not thermally insulated;
2.0–2.9, if low-effective thermal insulation is present;
1.0–1.9 with medium-level thermal insulation (walls 2 bricks thick, few windows, simple roof without openings);
0.6–0.9, if the thermal insulation is good (the walls are insulated, there is a contour seal on doors and windows, double-glazed windows).

If your premises are not industrial (ceiling height no higher than 3 m), you can use the data from the table.

Table: dependence of the required gun power on the area of the room

Heat gun power, kW	Volume of premises in a new house, m3	Volume of premises in the old building, m3	Area of a modern greenhouse with insulated glass, m2	Area of a glass greenhouse without thermal insulation, m2
5	70–150	60–110	35	18
10	150–300	130–220	70	37
20	320–600	240–440	140	74
30	650–1000	460–650	210	110
40	1050–1300	650–890	300	150
50	1350–1600	900–1100	370	180
60	1650–2000	1150–1350	440	220
75	2100–2500	1400–1650	550	280
100	2600–3300	1700–2200	740	370
125	3400–4100	2300–2700	920	460

An overly powerful heat gun in a small room can cause a fire. Use appliances of suitable power (or with a regulator) and/or do not leave them unattended.

Principle of operation

A factory-made or home-made electric heat gun has the following principle of operation: a powerful fan is located in the device body, driving the air flow through a heating element installed in the device body. With its help, the air is heated, and then, in a warm state, it enters the heated room.

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There are 2 types of heat guns: electric and gas.
The room where an electric heat gun is to be used must be equipped with a ventilation system or exhaust hood.

The design of an electric heat gun includes the following elements:

Frame. Made from fire-resistant materials.
A heating element. The most commonly used tubular electric heater is a heating element.
Powerful fan.
Three-core cable with a cross-section of at least 2.5 mm2.
Electric plug.

The specific power required to warm up a particular room is calculated from the number of heating elements installed in the device body. The more there are, the more efficient the heating is and vice versa.

It is a mistaken belief that the rate of heating of the room area depends on the speed of rotation of the fan impellers. The rate of filling the room with warm air directly depends on the power of the tubular heating element. The fan distributes the flow evenly throughout the room.

Important details, safety rules

Homemade electric guns are much more dangerous than factory ones, because during their assembly it is not always possible to take into account all the nuances. The basic safety rules when heating with such devices are:

Never leave a running appliance unattended, even if it is equipped with residual current devices and appears completely safe.
Do not leave diesel or gas heat guns turned on overnight in a residential building; do not risk the lives of people and the safety of property.
For heat guns using wood, diesel fuel or gas, be sure to equip a good hood and carefully monitor its serviceability, promptly clean it from soot and combustion products.
Fuel tanks and gas cylinders should not be located close to a working gun to avoid fire.
An open flame must be covered with a protective screen so that embers or splashes of burning diesel fuel do not enter the room.

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Stages of making an electric heat gun with your own hands

Making a gun that is powered by electricity is very simple. For this purpose, improvised means are used. So:

We remove the heating element from any unused electrical appliance with a heating element. Ideal options are irons, electric stoves, boilers and the like. We shorten the removed heater by half its length. This will reduce the resistance in the heating element and increase the current carrying capacity. Thus, we will increase the power, therefore, the gun will heat more efficiently.
Now you need to prepare the body. To do this, we use a 60-80 cm piece of asbestos-cement or steel pipe. A spiral or heater is attached to the inside of the pipe. We leave space for installing a fan.
We connect an electric cable to the ends of the heating element. For this, it is advisable to use a three-core wire with a cross-section of over 2.5 mm2.

Before using the electric heat gun, be sure to provide grounding!

At this stage we connect the fan shaft to the electric motor. The propeller impellers should rotate freely in the pipe without touching its walls. The more freely they rotate, the higher the level of heat transfer efficiency.
We complete the assembly by securely fastening the fan to the end of the pipe.

The power supply for the heating element and the electric motor with the propeller is done separately.

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You will need: sheets of metal, el.
coils, wire, and definitely a welding machine. This is one of the many ways that an electric heat gun can be made.
Homemade devices are, in principle, not electrically safe. Therefore, they should only be used under supervision. Another negative factor is the burning of oxygen. For this reason, it is recommended to use an electric heat gun in rooms with a ventilation system.

How to make a heat gun using diesel fuel

A diesel heat gun is a more complex version of the heater than an electric one. Based on their mode of action, the following types are distinguished:

Gun heater using diesel fuel with direct air heating. Used for heating small areas.
Diesel fuel gun with indirect air heating. Used as diesel heating for warehouse or industrial premises.

The first type includes heat guns with a simple and effective operating principle, but they are also extremely dangerous. The housing consists of two parts: one burns diesel fuel, the other contains a fan that forces hot air through the flame. Due to the fact that the entire process takes place openly, fuel combustion products enter the heated room along with the hot air flow. Therefore, a diesel heat gun for a garage is most often used.

The second type is more complex in design and less effective, but it is absolutely fireproof and does not harm health. A self-made diesel gun is used as a heat exchanger heater, which heats the area of the room by releasing heat into the air. A smoke channel is connected to it, through which exhaust gases exit. Gasoline is also used as fuel. A gasoline burner is slightly more expensive due to the fact that the cost of fuel is higher than diesel fuel. A do-it-yourself gasoline burner is made using the same method as a diesel one.

Rules of care and use

The apparent simplicity of manufacturing a structure can be the cause of many errors. Therefore, the owner of any heat gun must adhere to certain recommendations:

The pipe for removing combustion products must be located at least 2 m from flammable objects.
Do not use the heater if there are gasoline vapors in the air. High humidity is also unacceptable.
If the equipment has air filters, they must be replaced or washed with soap every 700 hours of operation.
There must be a pause of at least 5 minutes between turning off and then turning on the device.
The fan must be cleaned at the beginning and end of the heating season.
Diesel gun fuel filters must be cleaned every 4 months of operation.
When storing the equipment, it is necessary to cover it with polyethylene or thick cloth so that the device does not become covered with dust.
Provide manual cooling: turn off the burner and turn off the fan when all equipment has completely cooled down.
To prevent fuel leakage, the heat gun must be installed only on a stable and level surface.
Heat guns can only be refueled when they have completely cooled down.
It is forbidden to block the switched on device, especially the openings for air supply and outlet. It is also prohibited to place things to dry on the equipment that is turned on.
Only a day's supply of fuel can be stored near the heat gun and other devices. The main stock must be stored in a special room.

The effectiveness of heat guns has long been proven by their practical use: if you need to dry something or heat a room, there is no better option. Moreover, the design of this equipment is very simple, which makes it possible to make this heater yourself. The devices are very powerful, so you need to be very careful when using them.

Stages of making a diesel heat gun with your own hands

Let's consider a method for making a diesel heat gun with your own hands of the first type, that is, with direct heating of the air. So, for assembly you need to prepare the following materials:

Tank or container for burning fuel.
Tubular structure for making the outer casing. It is recommended to use fire-resistant metal.
Pipes for the combustion chamber. We use any refractory material.
Fuel burner.
Compressor or pump.

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A heat gun produces a huge amount of heat
. Manufacturing steps:

A fan is inserted into the pre-prepared pipe casing of the device.
A fuel tank is installed next to the gun body. With a distance between them of two to three centimeters. For greater confidence, you can add a layer of thermal insulation to the tank.
The combustion chamber, made of a pipe half the size, is installed inside the housing.
Now we install the fuel injector into the combustion chamber and connect them with a metal tube.

Before starting a diesel heat gun, be sure to check the fuel cell connections for leaks.

We connect the pump to the fuel tank and injector.
We install a protective reflective screen directly in front of the combustion chamber.

Now, having checked the connections and each component of the diesel fuel burner, you can begin operating the heat gun.

How to make a gas heat gun

As practice shows, a homemade gas burner is not the easiest option. However, using your own experience and special responsibility, you can make it yourself. A DIY gas gun has various uses. Gas guns are most often used for garages and construction sites, as they dry walls well. As in the previous case, there are two types: