Car body straightening work often comes down not only to basic skills in working with standard tools. Almost always, you will need to know the design features, the geometry of the body parts, and the observance of banal accuracy plays an important role. Even with a very rich experience and knowledge in this matter, you will need to use a special tool, which is a spotter.

This word is used throughout the world for all types of resistance welding tools (from the English spot - "point"). In the former post-Soviet space, this is the name for one-sided welding machines used for repairing body surfaces of various types of vehicles, and which include a reverse hammer. The main purpose of using a spotter is to prevent the need to replace a damaged part, to carry out spot repairs instead, which saves on running costs.
Any professional straightener knows that spot welding is indispensable for complex body geometry. The surface on the machine with this tool is processed in any places, regardless of the difficulty of access. Working with the instrument is quite simple and does not require long training - that is why the devices are widely used.
The device, in fact, is universal - well suited for straightening body parts, such as: hood, sills, doors, fenders, etc. The main function of the device is to create a straightening force with fixation on the outside of the part.
In a nutshell, a small section of a body element is heated with the help of a spotter, which must be eliminated from unintended deformation. At the same time, the car itself is caused a minimum of damage.
The simplest spotter tool consists of:
Any enclosure that is reasonably safe to work with can act as an enclosure. The spotter can be made independently, but such a device is unlikely to cope with long-term working conditions - only factory models are adapted to this.
The welding procedure includes the following steps:
The processing process itself does not require the application of special efforts and straightening is quite possible to carry out in a standard garage.
In total, there are two main types of tools: transformer and inverter. Depending on the method and area of use, two more classes are distinguished: for body welding using the contact method and for straightening.
Straightening spotters are small devices designed for small work. They require the mandatory installation of a reverse hammer and additional attachments to complete the repair. In addition, the design may include special pliers. However, many of these devices have low power, are prone to rapid overheating, and therefore are not able to provide high-quality welding.
In addition, spot welding equipment can be classified according to the consumed supply voltage from the mains. Standard tools are rated at 220V, and the most powerful at 380V.

The work of smoothing the dent begins with the fact that the electrode is supplied with current from the welding machine. For straightening, a reverse hammer is used, which can be replaced with a pointed stop. The impact on the deformable surface must be carried out until it is completely leveled. Upon completion of all operations, the processing site must be cleaned, since there are electrode slags on it.
The algorithm for straightening work includes the following stages:
To perform the above algorithm, minimal knowledge of working with a welding machine is sufficient. If the spotter is equipped with a set of nozzles, this will allow you to work with any fasteners.
Despite the similarity of the algorithms of work, all works on a small scale have some differences, namely:
It may be necessary to use additional attachments.
To eliminate such deformations, large-scale actions will be required, the distinctive features of which will be:
Their useful properties include:
These include the following variations:

As a rule, devices made in China immediately come with the maximum number of accessories and attachments and are even equipped with a special trolley, so you don't have to buy anything.
At the same time, European models do not often boast a complete travel kit. However, due to the simplicity of the design of the tool itself, there are no problems in using "non-native" attachments when working.
Usually, in the design of equipment from Western manufacturers, a copper secondary winding of the transformer is necessarily used, which makes it possible to reduce power consumption at the same current, which significantly reduces the load on the network.
They are also equipped with special smart microprocessors, which will exclude possible erroneous metal burning. This function is especially relevant recently, when the world auto industry began to use metal sheets of very thin thickness (up to 0.6 mm.).
A huge role in the price of a spotter is played by parameters that indicate the current consumed by it, the general qualities of performance and functionality. The higher each of the listed parameters, the more and the price of the device. Thus, before buying, you should decide on the amount of work for which you need equipment. If one-time small work is expected, then you should not fork out for professional equipment. If it is supposed to constantly provide qualified services using this tool (for example, within the framework of the service station), then you should attend to the acquisition of powerful equipment.
Among the significant price factors, the following trend can be established:
One of the most budgetary, but at the same time reliable devices on the Russian market. At the end of 2019, it became the most demanded equipment among the devices of this type among Russians. Compatible with attachments from other manufacturers.

Specifications:
| Name | Index |
|---|---|
| Supply voltage, V | 220 |
| Power consumption, W | 6 |
| Current frequency, Hz | 50 |
| Minimum welding current, A | 200 |
| Maximum welding current, A | 1500 |
| Maximum thickness of parts to be welded, mm | 2 |
| Weight, kg | 14 |
| Price, rub. | 14000 |
A highly specialized apparatus for car body repair. It is supposed to be used only in conjunction with a more powerful model, since its main function is to weld studs for subsequent straightening of parts using a reverse hammer.

Specifications:
| Name | Index |
|---|---|
| Maximum current, A | 15 |
| Power, W | 3500 |
| frequency Hz | 50 |
| Diameter of studs to be welded, mm | 2020-03-02 00:00:00 |
| Weight, kg | 4 |
| Class | "Semi-professional" |
| Price, rub. | 8000 |
The tool is designed to remove dents from vehicle bodies. It gained well-deserved popularity due to its convenient pistol, the presence of a microprocessor discharge, and a simple control panel.

Specifications:
| Name | Index |
|---|---|
| Maximum welding current, A | 3800 |
| frequency Hz | 50 |
| Net weight, kg | 23 |
| power, kWt | 7.4 |
| Item height, mm | 235 |
| Voltage, V | 220 |
| Item width, mm | 360 |
| Mains fuse, A | 16 |
| Item length, mm | 225 |
| Price, rub | 24600 |
This multifunctional spotter is designed for tricky body straightening jobs. Equipped with overheating microprocessor and automatic input of welding mode. The main duty cycle of the device is designed for 10 minutes of operation at rated load, excluding overheating.

Specifications:
| Name | Index |
|---|---|
| Maximum current, A | 5200 |
| Power, W | 20000 |
| Thickness of sheets to be welded, mm | 2 |
| Running time adjustment | machine |
| Cooling | aerial |
| Voltage, V | 220-380 |
| Weight, kg | 78 |
| Price, rub | 30000 |
Professional grade tool for fixing steel car panels. Allows for the smallest repairs that do not require disassembly of the machine. Has a comfortable pistol grip operating on an automatic charge and an intuitive control panel.

Specifications:
| Name | Index |
|---|---|
| Maximum current, A | 3800 |
| Power, W | 5200 |
| Welding adjustment | Machine |
| frequency Hz | 50 |
| Voltage, V | 220-230 |
| Additionally | portable type |
| Weight, kg | 24 |
| Price, rub | 43000 |
An excellent tool for professional work in a car service. Fully copes with the performance of one-sided spot welding.It has increased power, the body is made in a dust and moisture protection version.

Specifications:
| Name | Index |
|---|---|
| Maximum current, A | 4400 |
| Power, W | 11000 |
| frequency Hz | 50-60 |
| Weight, kg | 67 |
| Additionally | manual adjustment of the welding time possible |
| Price, rub | 46000 |
This professional unit has been specially designed for use in the auto repair industry. Focused on welding thin-walled metal (welding two sheets of 1.5 mm thickness is not a problem). Designed for correcting deformed surfaces and welding washers, screws and nails.

Specifications:
| Name | Index |
|---|---|
| Weight, kg | 30 |
| Voltage, V | 380 |
| Overall dimensions, mm | 390x260x225 |
| power, kWt | 11 |
| Welding current max, A | 3000 |
| Power at 50% load, kW | 3.0 |
| Thickness of materials to be welded (each) max, mm | 1.5+1.5 |
| Price, rub. | 73000 |
In straightening works today it is simply impossible to do without spotters, because they significantly reduce the labor intensity of the process and improve the quality of work. You can buy them in any specialty store or order them on a trustworthy online trading platform (significant money savings are possible). The market for spotters and accessories for them is large enough, so choosing a model is not difficult. However, not all devices are complex technical goods, so simpler models will have a minimum warranty period.
A properly selected model, combined with a well-defined scope of work, will allow you to get the best result.