Manual arc welding: what is, types of MMA welding machines, how to choose, the best models

For those who want to learn how to weld metal parts together, it is best to start with manual arc welding (RDS). This method has the international designation MMA. First you need to figure out which device to buy (type of equipment) and with what characteristics. Tips on this topic, as well as a rating of the best household and semi-professional models, compiled taking into account the parameters and reviews, will help you make the right choice. Then your machine will cope with the upcoming tasks, and the welding training process will be faster.

The selection of goods was carried out on the basis of reviews, opinions and ratings of users posted on various resources on the Internet. All information is taken from public sources. We do not cooperate with manufacturers and trademarks and do not call for the purchase of certain products. The article is for informational purposes only.

What is MMA manual arc welding

Manual arc welding is called so, since the process of burning the electrode and leading the arc to form a seam are carried out completely in manual mode. The electric arc was discovered long ago, but was first used to connect metals in 1882. In 1907, the process was improved by coating for electrodes and received the international designation Manual Metal Arc (MMA).

The essence of the manual arc welding process is to connect the current source to the network. Two wires (+ and -) emanate from the device. One joins the product, and the second is equipped with an electrode holder. An electrode is inserted into it - a metal rod with a diameter of 1.6 to 6 mm, coated with a coating. Tapping on the surface leads to circuit closure and an electric arc.

The arc temperature is 5000 degrees, so due to the thermal energy the edges of the metal being joined and the rod of the electrode itself melt. Molten metal is called a weld pool. To protect it from the effects of ambient air, a gas cloud is needed. This role is played by the coating of the electrode, which melts and creates a protective environment. Due to this, the metal hardens without pores. After crystallization, a slag crust forms on the surface of the seam, removed by lightly tapping the hammer.

If you swap the wires (minus connect to the product, and plus to the holder), you get the opposite polarity. In this case, the current will move from the product to the electrode, which reduces heat input and is in demand when welding thin products. With direct polarity (plus to the mass, and minus to the holder), the voltage moves from the electrode to the workpiece, which accelerates the melting of the edges and increases the welding speed.

To control the process visually, the welder must be in a protective mask with a light filter. It prevents damage to the retina by UV and infrared rays, protects from bright light and prevents the escape of scale on the face.Mandatory personal protective equipment is gaiters, heavy clothing and boots. There should be a hat without a visor.

Detailed video tutorial on manual arc welding

Advantages and disadvantages of manual arc welding

MMA metal welding technology has several advantages and disadvantages that should be considered when choosing a method for specific tasks.

Types of welding machines for manual arc welding

It is important for a novice welder to know the types of welding machines for manual welding, selected depending on the thickness of the metal being welded, the type of steel and the frequency of use of the equipment. The price of the models is also different, so it’s worthwhile to delve into this issue in more detail in order to buy a device suitable for future activities. Equipment can be divided into three categories:

Inverters

One of the most compact devices with a connection to 220 or 380 V. It uses small transformers, a diode bridge and an electronic board with keys. The unit receives from the network an alternating current with a frequency of 50 Hz and converts it to direct, passing through a special filter. Then the voltage again becomes variable, but with an already increased frequency - 100 kHz. After that, the amplitude of the volt decreases to 48-90, and the current increases to 160-200 A.

Welding inverter with cover removed.

At the output, the current is again converted to direct current. There are universal inverters where, in addition to MMA welding, it is possible to install a coil with a wire and connect a torch from a semiautomatic device for MIG / MAG welding. “3 in 1” models are also capable of cooking with a non-consumable tungsten electrode in argon medium (TIG). Of course, the cost of universal inverters is higher than usual, but their functionality is wider.

Universal welding inverter.

Rectifiers

These are installations for manual welding in industrial conditions. They convert alternating current to direct without changing the oscillation frequency. Most often, 380 V is required for connection. They are distinguished by smooth seams created with a characteristic rustle. They are used for manual welding of critical products, but they are expensive and not convenient in transportation, so they are more suitable for stationary use.

Welding rectifier.

Transformers

Welding transformers are MMA welding machines at the most affordable price due to the simplicity of design. It is a coil with primary and secondary windings. Due to this, the voltage decreases, and the current increases. Changing the distance between the coils allows you to adjust the welding current. The work is carried out on alternating voltage. There are models for 220 and 380 V. There are compact devices for carrying on the shoulder and large industrial installations. Due to AC welding, they are suitable for non-critical structures.

Welding transformer.

How to choose a welding machine for manual arc welding

It is necessary to choose welding equipment for manual arc welding based on the upcoming tasks for joining metals, including the maximum thickness of the workpieces, place of work, volumes and type of steel. Here are the key features of the equipment and recommended values ​​for various activities.

Working voltage

An important parameter on which depends on where it will turn out to cook with the apparatus:

• Household models on 220 V, which can be connected to ordinary outlets. Only suitable for welding steel, section up to 10 mm.
• Universal models designed for 220 and 380 V. They are suitable for both garage and production. They can weld metal up to 20 mm in thickness.
• Industrial installations with power supply 380-580 V. Designed for joining workpieces with a thickness of 10-50 mm.

Where the voltage is often "sagged" (a weak power line in a garage cooperative, a remote village, in the country), it is advisable to choose a welding machine with an input current of 160 V. This will allow manual welding without installing a voltage regulator in the circuit.

Welding Current Adjustment Range

The thickness of the penetration depends on the current strength. The adjustment range of some devices is 160-200 A, others 200-250 A. Industrial devices can have a maximum value of 400-500 A. If you buy an inverter with insufficient current margin, the metal from the electrode will not be able to melt inward, but will stick on the surface. Such a seam will be weak and not tight.

• For welding steel with a cross section of 1-2 mm, amperage is sufficient 60-100 A.
• To cook workpieces with a thickness of 3-5 mm, choose an inverter with an indicator 160-200 A.
• If welding of thick parts of 6-20 mm is a priority, then a professional machine with amperage is required 250-400 A.

Duration of inclusion

This characteristic is indicated by the abbreviation PV and is measured in percent. A PV of 40% means that out of 10 minutes, the apparatus will be able to cook at maximum current continuously for 4 minutes, and the rest of the time will be required to cool. If you need to use the machine for a short time (welding with short seams, where interruptions often occur for subsequent marking and cutting of workpieces), you can save money and buy a machine with a small PV index, since it will have time to cool down during downtime.

In cases of prolonged welding, you need to buy an inverter with a PV of 80 or 100%, which will be able to cook practically without stops. The second option is to purchase a device with a high maximum current indicator (for example, 250 A). And although its PV at a maximum will be 40%, but at a value of 160 A, the PV will be 100%. And this is enough for continuous welding of sheet steel with a section of 3 mm.

Open circuit voltage

Since the welder often holds onto the workpiece or even stands on it in the process of conducting the seam, it is necessary to ensure safety from electric shock. To do this, the voltage during arc closure is reduced to a value of 12-48 V. This avoids electric shock. But as long as the arc does not burn (the circuit is open), the idling is held at higher rates.

This is necessary to more easily close the contact and excite the electric arc. The higher the idle, the easier it is to ignite the electrode. This is especially felt when welding rusty iron or poorly peeled paint. It is better for a novice to look for devices with an indicator of 70-90 V. More experienced welders need 60-70 V.

Power consumption

The value varies in different models from 4 to 20 kVA. This determines how thick the cross-section of the wiring in the mains should be. If the power of the device is overstated for a household outlet, the wiring will melt. Therefore, for giving, transformers with 5-7 kVA are needed. If welding is planned in the field from a gas generator, it is better to find a 4 kVA apparatus. There are no restrictions for industrial versions, since in factories, the connection of powerful equipment is incorporated in the calculations when designing electrical networks.

Protection against dust and moisture

In the characteristics of the welding machine, the housing is protected from ingress of solid particles and water (IP). The first value is always “2”. This implies that solid parts with a diameter of 12 mm and above are not penetrated into the housing. This means that the jacket will not be sucked by the fan blade, and your fingers will not get to live parts.

The second value can vary from “1” to “3”. In the first case, the device is protected from vertical drops, and in the second from rain, even if the spray falls at an angle of 60 degrees.If you work under the roof, it does not matter, but for outdoor activities IP23 protection will help to finish the work on the street, despite the beginning of rain.

Ventilation system

In all devices for RDS ventilation is provided, which removes heat from the transformer and the board to the outside. Often, the system is implemented as a fan and perforation on the body. When overheating, the protection is triggered, and the inverter shuts off until it cools down. The presence of ventilation holes leads to the fact that the dust is pulled into the housing and purging is periodically required.

In industrial models, there may be water cooling. In it, a mixture of alcohol and distilled water is circulated through the channels using a water pump. The liquid removes heat from key electrical parts, extending the operating time of the device. But such goods are more expensive, so the purchase is justified only by the need to continuously cook for 5-7 hours every day.

Temperature range for operation

If you have to work by manual welding in a heated room, then this characteristic is not important. But for those who work in cold buildings or on the street, it is worth paying attention to the temperature range. Often inverters are allowed to use up to -10 degrees. There are special models that work properly at -20 degrees.

At a positive maximum temperature (which is +40 degrees on most models), the inverter will work faster thermal protection. Therefore, it is better to put the device in the shade on a ventilated area, then it will heat up longer.

Weight and dimensions

The size and weight of the welding machine affects the mobility of the welder and ease of transportation. For stationary use in a garage or workshop, dimensions and weight are not important. Unless it is required to provide a place for the apparatus 500x500x600 mm. But for field activities, it is worth buying a transformer with a weight of 3-6 kg. It can be worn on the shoulder and cooked at a height that does not require long mass cables and a holder, but only an extension cord for the power cord. Dimensions of compact inverters come in from 200x120x170 mm.

Additional features

The more additional functions the welding machine has, the easier it is to carry out manual welding and to impose a high-quality seam. A novice should pay special attention to this. Here is a description of some of the additional features of welding equipment:

• V.R.D. - reduces idling to a value of 9-12 V. This is necessary when welding is carried out inside or on a metal structure in order to further increase safety. The function is especially useful if welding is performed in a humid environment that increases current conductivity.
• Antistick - switching off the welding current when the electrode sticks. Facilitates the moment of disconnecting the sticky rod from the product, saves time and simplifies the learning process.
• Hot start - gives increased current (voltage V) exactly at the time of ignition of the electrode. Well suited for manual welding of rusty or painted metal. It helps to start the seam in the precisely designated place, without leaving electric traces from tapping with the electrode on the workpiece.
• Arc force - at the moment of sticking of the electrode, it gives a short-term increase in current strength (by 10 A) to prevent arc attenuation. Useful for manual welding of sheet steel.

Video. How to choose a welding inverter for manual arc welding

The best welding machines for manual arc welding MMA

Having considered the key characteristics, it will be easier for you to choose the device for upcoming tasks. Next, we present the rating of the best models that received the most positive customer reviews. Perhaps among them you will find one that suits the parameters for your needs.

The best MMA welding machines for 140-200 A

Transformers and inverters for 140-200 A are household models that are used in the country, in the courtyard of a private house, in the garage. They are suitable for a small private workshop. They are called household because of the connection to the 220 V network and the ability to weld only thin iron up to 4-5 mm in cross section. Here is a ranking of the best models in this category.

RESANTA SAI-140

Welding machine from a domestic manufacturer.The range of current strength is 10-140 A. There is a rotary controller with a painted scale. Two indicators on the case indicate a network connection and overheating. The casing of the inverter is completely made of steel, which protects the internal parts from shock. Idling 75 V facilitates ignition of the electrode. At a maximum current of PV, 70% is permissible. The housing has a degree of protection IP21. A wide shoulder strap simplifies transport and work at heights. This is quite possible, since the inverter weighs 4.3 kg.

 

Output. This is one of the cheapest inverters for manual MMA welding. Its cost is explained by simple equipment and a maximum welding current of 140 amperes. The unit is notable for the possibility of welding at a low voltage of 140 V. If your power line is weak, then this is the best option.

PATRIOT Max Welder DC-200

The second place is given to the American brand, manufactured in China. The inverter has a current strength of 10-200 A and an open-circuit voltage of 75 V. A wheel and a drawn scale are provided for setting the welding current. The front panel is equipped with two indicators that indicate the presence of a connection and overheating. The device is carried over a wide belt, which is not difficult to do with a weight of 4.5 kg. The holder from the kit is equipped with multi-position copper plates for clamping the electrode at different angles.

 

Output. This is one of the best home-class devices in a combination of price and performance. It is suitable for manual welding with electrodes up to 5 mm in diameter. Not every model is capable of this. The increased power allows the use of an inverter for welding hinges of gates, frames under the greenhouse, arbors. They will also succeed in cutting a corner with electric welding, which does not require the presence of additional tools (grinders, hacksaws).

Gigant MMA MINI GOS-180

This unit has bayonet connectors that allow you to quickly connect cables or reverse polarity. The welding current has a range of 20-180 A. The power of the unit does not exceed 4.7 kW, which allows operation from a household outlet. Idle here is 65 V. At the maximum current of the PV, 60% is obtained. The 25 mm² network cable does not heat up for a long time. The device confidently cooks with electrodes 1.6-3.2 mm in diameter.

 

Output. Despite the fact that this model is slightly larger than the above, it weighs less - 3 kg. This is an excellent choice for those who often have to cook at height (farms, gazebos, attics). From this weight less tired shoulder. The front panel of the inverter is also recessed inward, so the adjustment wheel does not cling to clothes - spontaneous settings will not go wrong.

RESANTA SAI-160PN

This model from Resanta is already equipped with a rigid handle for transportation and metal belt loops. The range of current is from 10 to 160 A.In addition to amperes, the welder can adjust volts, affecting the degree of meltability of the filler metal. The inverter is connected to a single-phase network. PV at the maximum will be 70%. The device is characterized by a particularly easy arc excitation due to 80 V at idle. Degree of protection IP21, air cooling is provided. The inverter weighs 5.7 kg.

 

Output. This is the cheapest model with a bright display. The screen allows you to visually control the current and volts. Protective clear glass prevents the panel from being damaged by scale and accidentally changing settings. The inverter confidently cooks from 140 V, so in the country it is indispensable.

Svarog ARC 200 REAL Z238N

This model is from a Russian brand assembled in China. The welding machine for RDS is available in an orange metal case with rubber pads. The power is 4.9 kW, and the welding current is set within 20-200 A. The minimum input voltage is permissible 160 V. Idling has an indicator of 60 V, and the duration of inclusion is allowed up to 60%. There is no “Arc Forsage” here, but users in the review praise the product for the clear operation of “Anti-sticking”. The unit weighs 4.6 kg. According to the passport, welding with electrodes with a diameter of 1.5-4.0 mm is allowed.

 

Output. This MMA device is notable for the rubberized corners of the case. They are located both on the upper and lower parts of the front and rear. This will not allow to break the casing on the pipes or the corners of the walls when working in tight conditions. Still, this design is less traumatic for the welder when worn on the shoulder.

CEDAR MMA-200 GDM

Another model from a domestic manufacturer. It is connected to a single-phase 220 V network and provides a current strength of up to 200 A. Confidently cooks with electrodes 3 and 4 mm in diameter. The source weighs 6.1 kg. The dimensions of the device 315x145x250 mm simplify transportation and storage. Power 6.5 kW allows operation from a generator or household outlet. The current can only be reduced to a value of 40 A, so sheet metal with a thickness of 0.8 mm cannot be cooked.

 

Output. This household model is notable for the presence of TIG welding. A TIG torch can be connected to the connector and cooked with tungsten electrodes. At the back there is a pipe for fixing the gas hose from the cylinder. Such a universal inverter is useful if you have to alternate manual welding with electrodes over thick "black" metal with stainless steel.

Svarog ARC 205B (Z203)

High-quality and powerful inverter for complex tasks.It has a power of 8.3 kW, so the connection must be through a socket with wires of 50 mm². The welding current is adjustable in the range of 10-200 A, where at the maximum PV it will be 80%. Idling 63 V gives easy ignition of the arc. It is convenient to control the set values ​​on the display. The dimensions of the RDS apparatus are 410x160x260 mm.

 

Output. The MMA welding inverter is notable for high-quality assembly, the presence of the TIG mode and long cables of mass and holder. This is a good machine for the demanding master. Another model stands out with a guarantee from the manufacturer for 5 years.

FoxWeld Wizard 202

The inverter with a welding current range of 20-200 A completes this rating category. It has a digital display, an overheat indication, and a start button on the front side. The powerful fan does not allow a stop in works in the heat. The welder has all the necessary functions to prevent sticking and burn through. Idle here is 62 V. The efficiency of the unit is 80%. Insulation class - F. Permissible input voltage - 180-240 V.

 

Output. We marked the MMA in the rating as the best for working with a long carry. If you often have to move around a large structure, this inverter cooks well even with an extension of 25 m. Welders note a soft arc in the reviews. They also rarely break and are hardy.

The best semi-professional MMA welding machines for 220-250 A

Inverters and transformers for 220-250 A are “borderline”. These are the most productive models for domestic needs and the "younger" for professional activities. Some of them run from 220 V, others are universal in power or require a connection to 380 V. Such MMA devices are worth buying for work in a garage, own workshop or small production.

Resanta SAI 220

Domestic brand at an affordable price. Has a current strength of 220 A with 100% PV at maximum. At the same time, it works from a household outlet and consumes 6.6 kW of power, so connecting in a house will not create problems. The manufacturer equipped it with afterburner and protective functions. The open circuit voltage is 80 V, so the arc is excited quickly. The model weighs only 4.9 kg, which is not bad for this class.

 

Output. This is a good MMA welding machine for starting a business when there is no way to invest a lot of money in equipment. A current reserve of 220 A is enough for manual welding and cutting. Inverter repair is inexpensive.A case is supplied with the kit, which simplifies storage and frequent transportation.

Fubag IR 220

Second place in this rating category is assigned to the device for RDS from the German brand Fubag. Goods are manufactured in China, which reduced the total cost. The inverter housing is made entirely of iron. There is a wide shoulder strap. When overheating, protection is triggered. The Arc Force, Anti Stick, and Hot Start features enhance the quality of manual welding. On the digital display it is convenient to control the input data. The current strength at PV40% reaches 220 A. Idling is 74 V. It can be cooked with a “squandered” network from 150 V.

 

Output. The MMA inverter stands out for its compactness. This is one of the smallest devices among semi-professional models. Its dimensions are 260x120x185 mm. Small sizes take up little space in the trunk of a car and at home in the pantry. This is the best option for field work.

RESANTA SAI-250

An inverter for manual arc welding with a welding current range of 10-250 A. It can operate on a voltage of 140-260 V. It is connected to a single-phase network. Idling of 80 V immediately ignites the electrode when you first touch the mass. The manufacturer equipped it with a full range of functions that facilitate manual welding. Model weighs 5.3 kg. Provides direct current, providing smooth and tight seams. If you cook at maximum amperes, the duration of the inclusion will be 70%.

 

Output. This is the best device in terms of power and price. Despite connecting to 220 V, it gives an honest 250 A, which is the maximum for a household appliance. It costs a little cheaper than competitors. If you need to weld metal with a section of up to 10 mm, then this is the best budget option.

RESANTA SAI-250PN

The rating is continued by a professional model from Resant with a current of 250 A. The MMA is powered by a single-phase network and consumes 7.7 kW. The front panel is equipped with a digital display and two controls. The controls are closed with a plexiglass shield, which prevents the settings from being knocked down or screen damage. The device can be carried by a belt or a rigid handle. The PV here is 70%, and the idle is 80 V. But the degree of protection IP21 allows the inverter to work only indoors during rain.

 

Output. This model differs from the above prefix “PN” in the index. The abbreviation indicates the guaranteed ability of the apparatus to cook under reduced voltage. This is the best option for working in the field from the generator or away, where the network parameters are unknown.According to customer reviews, they even manage to cook stainless steel, if you install the corresponding coated electrodes.

ELITECH IS 200H

A small semi-professional apparatus for manual arc welding with an amperage of 200 A. It consumes 7 kW of power. Allowed to work with electrodes from 1.6 to 5 mm in diameter. There are “Anti-sticking” and “Hot start”. The regulator is equipped with a relief, facilitating the capture of the wheel with your hands in thick leggings. Two indicators indicate network availability and temperature. Arc excitation occurs at a current of 68 V. PV at a maximum will be 60%.

 

Output. This is the best professional inverter for manual arc welding for compactness. Case dimensions are 220x105x155 mm. The device weighs 2.8 kg, so if you often have to carry welding on your shoulder, this inverter is for you. There is also a TIG mode for argon arc welding. With it, brewing aluminum or stainless steel is even easier.

Denzel MMA-200ID

The inverter from the Denzel brand completes the rating category for semi-professional manual arc welding machines. It cooks faultlessly when the voltage drops to 150 V. The front panel is equipped with a regulator for smoothly changing the current strength. Its value is set from 20 to 200 A. The manufacturer equipped the unit with the “Hot start” function. This is good, since the idle speed here is inferior to the competitors' models and is 56 V. The inverter weighs 6.5 kg.

 

Output. Although PV at maximum amperes is 60%, in practice, judging by the reviews, the device heats up much longer and does not go into emergency mode. Thus, if you often have to work with a current of 200 A, but there is no money for a model with more powerful characteristics, then this is the best option.