Your own welding machine always useful in the household, albeit infrequently, but it is very necessary, and sometimes without it, well, just nothing. Especially if you are used to making things yourself. Therefore, do-it-yourself microwelding, made from improvised materials and outdated household appliances- just what we need.
We will not consider the option of buying a factory welding machine, as this will require money, but we will immediately follow the path of making home-made mini welding at home. There are several quite affordable schemes of welding machines for self-manufacturing, but the most simple and low-cost apparatus is contact or spot welding.
So that there is no doubt right away why we will describe exactly the option as, for this we will clearly define that for this we will not need theoretical knowledge of the electrical engineering course and virtuoso mastery of locksmith skills. Everything will be simple, clear and accessible.
Preparation
The main part of all electric welding machines is a power transformer (if you do not consider modern electronic welding equipment, also called inverters). Therefore, first of all, we will need to get it from somewhere, and the most suitable and affordable option for this will be an old broken microwave oven. And the bigger it is, the better for us. More precisely, the more powerful its transformer will be and the stronger our welding.
If you want to find an old microwave oven, it’s not a problem by looking for it either from your closest friends (those who are richer), or by looking at free classifieds boards, where they are often offered for a nominal fee. From the insides microwave oven we will be interested in only one detail - this is a high-voltage transformer.
Here we will immediately determine, without going into particular technical calculations, that contact welding made from such a transformer from a microwave oven will be able to generate a welding current from 800 to 1000 amperes. This current is quite enough for welding together strips of metal up to 2 mm thick, and even from of stainless steel which for simple welding is a challenge.
Preparation of the welding transformer
The high-voltage microwave transformer is a steel core, recruited from thin steel plates and located inside its two windings of copper wire. We need the winding that looks smaller, it is considered primary and will be wound from a thicker conductor. The other winding (the one that is larger in size) will be secondary and we simply do not need it. Here it is in the first place and must be dismantled from the transformer.
To do this, you need to disassemble the transformer, or rather, its core, which is made of steel plates, tightly compressed and fastened together by two thin welds. Here we need to cut these welds, for which you can use either a hacksaw or a grinder with a thin circle.
Keep in mind! There may be transformers fastened with an outer tin casing and bolts. In this case, simply unscrew the bolted connections and carefully open the casing. Everything, problems with further disassembly should not arise.
Perform this operation of disassembling the transformer very carefully, since we still need the primary winding, therefore, in no case do we bend or scratch it when removing it. But we don’t stand on ceremony with the secondary winding, it can be cut and pulled out with a hammer and a chisel in parts, it will be much easier.
As a result, we have a whole and undamaged primary winding of the transformer and its steel core in the form of two separated parts.
Next, we wind the secondary winding of our future welding transformer. Here we still have to buy a piece of new insulated copper wire with a cross section of 50 mm2 or about 8 mm in diameter. To do this, we take it and wind it around the central E-shaped magnetic circuit of the core, making two full turns. We will need all such copper wire, taking into account the output to the welding contacts of about 50 cm, the only condition is that the winding must be made so that it is the middle of the conductor.
Then we assemble the transformer, while the primary winding should remain in its place, and our new winding made of copper wire should be placed instead of the secondary. We fasten the two parts of the core using the usual two-component epoxy resin and clamp the entire structure in a locksmith vice for a day. After the epoxy has dried, the transformer is completely ready for operation. Photo
Construction assembly
Having made verification measurements with a simple tester, when connecting the primary winding to a 220 V network, we have a voltage of about 2 V on the secondary winding, but with a force electric current about 800 A (this is not measured, but calculated - here we take our word for it). This current strength is more than enough to make a strong welded joint of two metal plates.
Now we make the body. To do this, you can use any materials at hand, such as wood, plywood, sheets of durable plastic or galvanized sheet. The main thing is to place the transformer itself and the bottom contact on solid foundation, since one of the conditions is a strong contact of the welding electrodes with the surface to be welded, which, in turn, is possible with the application of great efforts.
It remains to make welding contacts and the mechanical part of our welding machine will be completed. One of the contacts will be at the bottom and it will be fixed, so it is better to make its base from a wooden block 30 cm long, so it will be easier to attach it to the base. At the end of the bar, using the manufactured bracket, we fasten the welding electrode, to which we connect one of the wires of the power winding of the transformer.
Welding electrodes for microwelding can be made with your own hands from a copper bar with a cross section of 5 to 10 mm in diameter, making a slight sharpening at the end at the point of contact with the surface to be welded. It is better, of course, to use tungsten rods or special electrodes for this. resistance welding from an alloy of beryllium bronze with additions of zirconium.
We make the upper contact in the form of a lever. For this you can also apply wooden block or not very massive metallic profile in the form of a tube of small diameter. The only thing is that on a metal lever, the design of the welding electrode attachment will be more difficult, since it will also need to be isolated. At the base of the moving contact lever, we must provide a spring so that the lever in the normal state is constantly in the upper position. To do this, you can use a steel spring or an elastic rubber band.
At the end we complete wiring diagram mini welder by connecting a wire with a standard plug for a 220 V network to the ends of the primary winding of our power transformer, and it is imperative to provide a 220 V switch. For this, both the old wire from the microwave oven and any switch designed for a voltage of 220 V and current strength of 5 A, it is better if it is a push-type microswitch (mic).
Important! Don't forget to isolate well electrical connections and contacts.
Everything, your own hand-made mini welder for a summer residence or at home is ready and, as it turned out, making it yourself is not so difficult. Now you can safely weld small flat parts from various metals, but for this you will need to practice and gain practical skills.
And also you can watch the video on how to make a contact spot welding with your own hands and how you can use it.
The profession of a welder has long and reliably entered many industries and household. The need for it is almost everywhere. The availability of modern welding equipment allows you to both learn how to cook by electric welding on your own, and master the profession at a more serious level.
Elements necessary for the welder
In order to master the technique of working with welding equipment, you will need an understanding of not only the physical processes when working with metal, but also a set of knowledge about welding machines, as well as various malfunctions, technology features, and other “pitfalls”. You need to be able to understand the intricacies of the profession of a welder at every stage - from preparatory to final. In vocational schools, training in this profession takes two to three years.
What you need to understand before learning how to cook with electric welding?
- be able to select the correct mode to work with various materials(steel, alloys, non-ferrous metals);
- know the various techniques for creating a weld;
- be able to correctly select electrodes and welding wire;
How to learn electric welding on your own?
If the goal is not to become a professional upper class, then it will be enough to master the key techniques and understand the basic concepts, and you can already experiment with welding work in the backyard.
So where to start?
First of all, you will need a welding machine and electrodes. It is better to start with electrodes with a diameter of 3 mm - they are suitable for most tasks and do not load the electrical network very much. Devices according to the principle of operation are divided into three categories: transformer, rectifier, and inverter. Inverters are the most compact, lightweight and easy to use for beginners.
Choosing a welding machine should be based on the purpose of the work. Then you need to select a few metal fragments on which you can practice. You will need a bucket of water, a hammer for knocking down slag, and also metal brush for surface cleaning. From overalls and protective equipment you will need:
- a mask to protect the face and neck with a special light filter (for example, a chameleon mask);
- thick gloves;
- overalls made of durable fabric, with long sleeves.
Do not forget about the precautions: there should not be combustible or easily flammable materials nearby, and the electrical network must be able to withstand the loads that occur during the operation of the welding machine.
The first steps in learning how to cook with electric welding
Care must be taken to ensure grounding - an appropriate clamp must be firmly attached to the workpiece. Then you need to check the cable - how well it is insulated and how well it is tucked into the holder.
After connecting the "mass", you can select the value of the current strength - depending on the electrode and the materials with which it is supposed to work.
Before igniting the arc, the electrode is set to the workpiece at an angle of about 60 degrees.
Electrode holder When moving slowly, sparks will appear - this means that the welding arc should appear. To create it, you need to place the electrode so that the gap between it and the surface is no more than five millimeters. The same rule should be followed in further work.Gradually, the electrode will burn out. Don't be in a hurry to move it. The speed of the electrode movement depends on many factors - they will be disclosed in more detail during practice.
What to do if the electrode sticks? It is enough to slightly swing them to the side.
To create a stable welding arc, it is desirable to maintain a distance of 3 to 5 millimeters between the end of the electrode and the surface of the workpiece. In the case of an arc 2-3 mm long, which refuses to ignite, you can increase the current.
Features of the welding arc and polarity when creating a seam
When trying to weld a bead, one should strive to shift the molten metal to the center of the welding arc.
The electrode moves smoothly horizontally, accompanied by oscillatory movements. Thanks to this, a beautiful and high-quality seam is obtained. To learn how to cook with electric welding, how
Weight - for arc weldinga professional, you need to know how welding with direct polarity differs from reverse.
An electric arc is formed when an alternating or direct current is supplied from a power source. If the positive power pole (anode) is connected to the workpiece, then this means that arc welding has a straight polarity.
And if a negative power pole (cathode) is connected to the part, arc welding with reverse polarity is obtained. The electric arc causes the metal rod of the electrode to melt and mix with the molten material of the workpiece, forming the so-called weld pool. In this case, slag is formed, which comes to the surface.
How to cook using electric welding with a different size of the weld pool?
Depending on the position of the bath in space, as well as taking into account various welding modes, the design of the parts to be joined, the size and shape of the edges, as well as the speed with which the arc moves on the surface, the size of the weld pool may vary. As a rule, its dimensions can vary in the range:
- from 8 to 15 mm - width;
- from 10 to 30 mm - length;
- up to 6 mm - depth.
How is arc length calculated? This is the distance from one active spot located on its surface to another (which is located on the molten surface of the electrode). When the electrode coating melts, a gaseous atmosphere appears near the arc and above the weld pool, which displaces air from the welding zone, preventing it from affecting the molten metal. Also, pairs of alloying elements of both the base and electrode metals get here.
In addition, slag protects against the oxidizing effect of air, because it covers the surface of the weld pool. And thanks to him, the metal is cleared of harmful impurities. Slag is formed as the arc is removed and the metal crystallizes in the weld pool during the formation of the seam.
About the techniques for forming a seam
Before you learn how to cook by electric welding yourself, you should master various welding techniques for connecting metal parts. Proper maintenance and movement of the electric arc is the key to a quality seam. If the arc is too long, then the metal will oxidize and become saturated with nitrogen, spray with drops, and form a porous structure.
Overlap seam
The welding arc moves forward along the electrode axis. Thus supported desired length arc, which is affected by the melting rate of the electrode. The length of the electrode decreases gradually, just as the distance between it and the weld pool increases. To prevent this, the electrode is supposed to be moved along the axis, observing the synchronism of its shortening and movement in the direction of the weld pool.
Ceiling seam
The electrode diameter depends on the thickness of the welded setalAnother type of roller is called thread. Such a bead is formed in the process of moving the electrode along the axis of the weld being welded. As for the thickness of the roller, it depends on the diameter of the electrode and the speed with which it moves.
About the width of the roller, we can say that it is usually 2-3 mm larger than the diameter of the electrode. This results in a fairly narrow weld seam. Its strength is not high enough to create a strong structure. How to fix it? It is enough when the electrode moves along the axis of the weld to make an additional movement of it - across the axis.
Tee seam (with one-sided cutting)
The transverse displacement of the electrode during operation makes it possible to obtain a sufficient width of the seam. This is done by reciprocating oscillations of the electrode, the width of which is determined individually for each specific case. Here it is necessary to take into account the position of the seam, its size, the shape of the groove, the characteristics of the materials, as well as the list of requirements put forward to the design. It is customary to consider the normal width of the seam from 1.5 to 5.0 electrode diameters.
Welding seam with electrode support
It is formed with rather complex, triple movements of the electrode. Exists in several variations. The trajectory of movement in classical arc welding must be such that the edges of the parts to be joined are melted, and at the same time sufficient molten metal must be formed to form a weld of a given shape.
Cutting and joining seams
How to learn how to properly weld torn seams by electric welding? If the electrode burned out almost to the end, then you have to stop to replace it. Before resuming work, the slag is removed and the process can be continued.
The arc is ignited at a distance of 12 mm from the crater (this is a depression that appeared at the end of the seam). The electrode returns to the crater to form a fusion of the new and old electrodes, and then continues its movement along the initially chosen trajectory.
Advantages and disadvantages specific to manual welding
Advantages:
Flaws:
- rather harmful working conditions;
- the quality of the seams directly depends on the qualifications of the welder;
- Efficiency and productivity are quite low (compared to other types of welding).
Video: How to learn to cook with electric welding
Welding is rightfully considered one of the most common metal joining technologies. Not a single building can do without welding, and a welding machine is an indispensable thing in the arsenal of any home master. Weld a gate, a fence, a reinforcing cage, weld hinges, assemble the base for a greenhouse, an aviary for a dog, put up a gate - there is a use for welding everywhere.
Also welding works are one of the main technological elements. But where to start welding, and most importantly - what nuances you need to pay attention to? In this article, we will answer the following questions:
- How to choose a welding machine.
- On what current to cook.
- What equipment is required.
- How to get quality welds.
- How to cook different metals.
Welding work - required theoretical minimum
You need to learn welding using the most common technology - manual arc welding (MMA for short - from the English abbreviation "Manual Metal Arc"). Moreover, it is necessary to cook using an inverter welding machine. Why an inverter? Inverters issue D.C. with a high degree of stabilization. They are lightweight, portable (can be carried by throwing the strap over your shoulder). They allow you to make all the settings "for yourself" even for a novice welder. Inverters, unlike a conventional welding transformer, withstand voltage fluctuations well, and during operation they do not “sag” weak electrical networks.
There are also more advanced welding technologies. For example, TIG (short for Tungsten Insert Gas). This is manual arc welding with a non-consumable electrode in an inert shielding gas (argon).
And MIG-MAG (Metal Inert/Active Gas). This is manual arc welding with automatic feeding consumable metal electrode (filler wire) in a protective inert/active gas environment.
These types of welding, due to the high price of the equipment and tooling used and the qualification requirements of the welder, are more suitable for professional work repair shops or factories. For example, for body repair car, restoration work, welding of thin metal parts, joining non-ferrous metals with increased requirements for the quality of the seam.
For most work "in the country", manual arc welding using an inverter welding machine is optimal.
But, despite the apparent simplicity (I bought an inverter and a vari), there are many nuances that must be taken into account in order to obtain a high-quality and durable seam. You should start by choosing a welding machine. How to do it?
On suburban area most often you have to deal with welding of the so-called "ferrous" metals. Hence: first, we determine the type and thickness of the metal that is supposed to be welded. The type and diameter of the welding electrode depends on this. The diameter of the welding electrode determines the amount of welding current. And only then, depending on this value, we choose a welding inverter.
The dependence of the electrode diameter on the thickness of the metal is presented in the following table.
The thicker the metal, the larger the diameter of the electrode is taken, and the greater the current of the welding machine should be. Each electrode (depending on its diameter) has a lower current limit. If the current is reduced below this limit, then a high-quality weld can no longer be obtained. For clarity, the welding current setting is summarized in this table.
On average, depending on the intended work, for every 1 mm of the electrode diameter, a current of 25-30 amperes is required.
Before starting welding, you should also estimate permissible load to your electrical network.
At a current of about 110A, the power consumption of the inverter will be from 3 to 4 kW. In normal electrical network there are safety switches for 16A, 3.5 kW. Accordingly, if these values are exceeded, the machine will turn off the electricity. Conclusion: either do not exceed the permissible power, or, if there is a need to cook at high currents, for example, with an electrode of 5 mm so-called. "five", put a more powerful machine and increase the cross section of the wiring.
For most construction work, a welding machine with a maximum welding current at 140 amperes (it is better to take the device with a small current margin, at 160-165A, and not back to back). The power of such an inverter is enough for the eyes to weld one of the most common electrodes with a diameter of 3 mm - the so-called. "troika".
The next factor that influences not only the choice of the inverter, but also the convenience of working with it is PV (On Duration). Why is it important to pay attention to this indicator? The duty cycle is defined as the ratio of the welding machine's time under load (net welding time) to the total welding cycle time (welding time + pause time).
The total welding cycle time is usually taken as:
- According to the European standard - 5 minutes at 40 ° C.
- In Russia - 10 minutes at 20 °C.
The optimal value of PV is 60%. Those. we work for 6 minutes (with a 10-minute cycle) - we rest for 4 minutes. If the PV is less than 60%, for example, it is only 15%, then this means that after 1.5 minutes of work, you will need to take a rest for 8-9 minutes. This will result in downtime. An attempt to increase the continuous operating time leads to the operation of the thermal protection of the device.
If the duty cycle of the welding machine is 60% at maximum current, then this is more than enough to work even at elevated temperatures. In practice, welding is not carried out continuously during these 6 minutes (the electrode does not burn so much), but with interruptions necessary to replace the electrode, clean the working seam from slag, and visually control the parts to be welded.
Welding practice
High-quality welding begins with the preparation of the workplace and necessary fixtures. It is best to get a welding table for this. Metal blanks and fasteners are placed on it: clamps, corners, etc., with the help of which the parts to be welded are fixed.
Iven FORUMHOUSE user
From personal experience, I can say that in welding sometimes a plane is very necessary, that is, a flat surface on which something can be welded. You need to be attached to this plane. Your first welding table I made out sheet metal 1250x2500x3 mm, 75 cm high. I used a profile pipe 20x40x2 mm as legs.
Any piece of metal can be used as a countertop. For example, we take a sheet 1000x2000x4 - this will be a countertop. From another smaller sheet - 1000x2000x2 mm - we make an average shelf.
With home-made design and manufacture of the welding table, a lot of room for creativity opens up. The quality of welding is largely determined by the convenience of working at the table. Accordingly, many craftsmen make a welding table “for themselves”.
Go ahead. The first assistant of any welder is all kinds of clamps, fasteners and corners. Without them, it is impossible to fix the parts to be welded on the table, observe required approvals and product geometry. FORUMHOUSE users prefer home-made clamps, made for each specific welding case, over factory-made clamps. This is justified for large volumes of work.
Sergeib3 FORUMHOUSE user
Welding work involves welding a channel, angle, pipe, etc. In each case, the clamp is unique.
A well-thought-out and well-made clamp turns into a third, truly versatile “hand” of a welder.
One of the main difficulties of any novice welder is the observance of right angles for the parts to be welded. It is not uncommon for carefully marked and cut workpieces (for example, rectangular) “leads” after welding, and it turns into a parallelogram. How to avoid it?
Metal shrinks as it cools. On which side there are more seams, and where they are thicker, the metal will lead there. Therefore, it is first necessary to temporarily grab the products to be welded, and not cook cleanly on each side. To fix the corners at 90 degrees, instead of the corners, you can use metal "kerchiefs" or jibs made of profile pipe. Moreover, the jibs are not welded end-to-end, but overlapped.
Another rule: if the corners and clamps help to maintain a right angle, then the flatness of the product can only be ensured by assembly on a flat surface. Before starting welding, it is necessary to check the diagonals, if they are gone, appropriate adjustments are made. Squares can be used to control right angles.
Also, when welding spatial structures that do not carry an increased load - an aviary for a dog, a frame for a greenhouse, etc. - you should not get involved in the total welding of all places, because 1 sq. mm of the weld can withstand a load of about 40 kg. The fewer seams in such structures (within reasonable limits), the less likely it is that after the metal cools down they will lead.
Nikola1 FORUMHOUSE user
I welded the hinges at the gate. First, I grabbed 2 halves of the wings, checked the ease of opening - they open easily. Then I scalded the loops with a continuous seam, I check the ease of opening - they open tightly. What did I do wrong?
This can happen due to the fact that the axis of the upper and lower loops did not coincide, the metal led, the loop was overheated during welding, its geometry was lost.
svar4ik FORUMHOUSE user
If, after tacking, the gate opened without problems, but not after welding, it means that the hinges are pulling due to the occurrence of residual welding stresses.
We deal with it like this:
- first we weld the hinges to the gate when they lie on assembly table;
- correctly position and grab all the details;
- lay the appropriate gaps (about 2 mm) between the loop and the post;
- loops should be 2 on each side (and not 3 or 4), it is easier to maintain alignment;
- to compensate for welding deformations, we weld the hinges to the frame and the door leaf crosswise.
Cast iron welding
Welding cast iron is considered a difficult task. Most often, electric arc welding of cast iron is carried out by the "hot" method. To do this, the workpieces to be welded are preheated to 600-650°C. IN country conditions, for welding not particularly critical structures, you can use the so-called. "cold" welding method - without preheating parts and using special electrodes.
Klez FORUMHOUSE user
Cast iron can be welded with stainless steel electrodes. How much I cooked them, nothing cracked, did not fly off. "Unkami" on the "straight" polarity is also cooked, but if it is rutile, then the welding is cracking at the seam.
For more information about the types of electrodes, see the article. .
Mictlayotl FORUMHOUSE user
I weld cast iron like this: I clean the place of welding, cut the edges and weld the part with either TsCH4 or UONIIs. I didn't see any difference from changing the polarity. I conduct welding at a minimum current, periodically cooling the parts to be welded in air.
When welding cast iron “cold”, overheating of the parts to be welded must not be allowed. Therefore, welding is carried out in short sections, 30-40 mm long, without welding the entire part at a time, with careful forging of the resulting seams with a hammer. Forging metal relieves residual stress in the metal, which prevents cracks in the weld.
It is also important to prepare the part before welding - to make a crack cut.
makar4ic FORUMHOUSE user
I once dropped a cast-iron cauldron on the floor. A 5 cm crack appeared, it’s a pity to throw away the cauldron, I decided to brew it.
The forum member did this:
- found the end of the crack;
- drilled the end of the crack with a 4 mm drill and cut the crack (chamfered at an angle) with a grinder, a 3 mm thick disk;
- welding was carried out with a TsCh electrode 3 mm in diameter;
- The forum member cleaned the resulting seam with a grinder with a cleaning disk.
The main problem of welding cast iron is that there is malleable, gray, high-strength cast iron. In addition, the fragility of the metal increases at the seam. Therefore, each case requires an individual approach.
If there are no special electrodes, then you can make a home-made one by winding a copper wire with a diameter of 1.2-2 mm over an electrode intended for welding steel (UONI 13/45, ANO-4) in a spiral.
Welding of galvanized metal
Timakval FORUMHOUSE user
I decided to weld a ladder from galvanized pipes. I ran into a problem - I can’t boil the parts the first time. Before welding, zinc was removed with a cleanup circle. What other secrets are there?
Dashnik: FORUMHOUSE user
Galvanized pipes are the same black metal, only coated with zinc. The place of welding should be cleaned to a shine, completely removing the zinc layer. The place where the "crocodile" clings also needs to be cleaned and securely fixed on the pipe.
It is important to remember that zinc evaporates intensively during the welding process. Emitted zinc vapors are hazardous to health. Therefore, welding of galvanized products must be carried out either in a room equipped with forced ventilation or outdoors.
If zinc cannot be removed, then you need to carefully consider the choice of electrodes. For welding mild steels, it is better to use rutile-coated electrodes. For example:
- ANO-4
- OZS-4
For welding low-alloy steels - electrodes with a basic type coating:
- UONI-13/45
- UONI-13/55
- DSK-50
Cook by making a reciprocating motion with the electrode. This contributes to the preliminary burnout of zinc. If the zinc layer on the workpiece is more than 40 microns, then to obtain a quality weld, the zinc layer must be completely removed.
Extension cable for welding inverter
It is often necessary to carry out welding work at a great distance from the electrical network (for example, when welding a fence). You need an extension cord of 30-50 meters, or even more. What wire size to choose for the normal operation of the welding inverter? Relying on practical experience members of the forum, we can conclude: for an extension cord, we take a copper flexible (stranded) two-core wire. Wire core cross section - 2.5 mm2. If grounding is supposed, then we take a three-core wire of the same section. We connect the load to a separate circuit breaker for 16 or 20A.
And at the end of the article - guide for a beginner welder from FORUMHOUSE:
- It is best to start learning how to cook by making a seam on a horizontal surface, in the lower position. This will allow you to quickly fill your hand and learn how to control the welding process.
- Before starting welding, the metal must be cleaned of dirt, rust, paint, otherwise a high-quality seam cannot be achieved.
- Keep the electrodes dry. The composition of the core must be similar to the composition of the metal to be welded.
- We maintain the slope of the electrode during welding at about 45 degrees, the distance from the electrode to the metal is 2-3 mm.
- You can lead the electrode at an angle forward and at an angle back. If the electrode is led backwards, the penetration will be deeper. If the angle is forward, then the penetration will be less, and the seam will be wider.
Butt welding connection. If the metal thickness of the workpieces to be joined is more than 5 mm, then the workpieces must be chamfered before welding. For butt-welded parts, we maintain a gap of 1-2 mm. First we grab the blanks using clamping devices, and only then boil them along the entire length.
Corner / tee welding connection. The welding seam has the form of a triangle. To obtain a high-quality weld, its thickness must be equal to the thickness of the metal being welded. If it is impossible to weld the required thickness of the seam in one pass (the metal is thick), we make several passes.
Welding vertical seam. With this type of connection, a lower current is set (selected individually) than, for example, when welding horizontally. Otherwise, the metal will get very hot and flow, and a high-quality seam will not work. It is better to lead the electrode from the bottom up, because. in this case, the molten metal is held by the metal that has already solidified from below.
Welding on direct and reverse polarity.
Straight polarity: to " +" ground is connected to the inverter. The holder is connected to "-".
Reverse polarity: earth is connected to "-". Derzhak - to "+".
. You can by following this link.
By what criteria to choose a welding machine, is described in this video. You can learn about all the advantages of working with a welding inverter from this video.
With this simple welding machine, you can cut thin metals, weld copper wires, engrave metal surface. Other applications can be easily found. Such a mini welding machine can be powered by 12-24 V.
The welding machine is based on a high-voltage high-frequency converter. Built on the principle of a blocking generator with a deep transformer feedback. The generator generates short-term electrical impulses that repeat at relatively large intervals. The clock frequency is in the range of 10-100 kHz.
The transformation ratio of this circuit will be 1 to 25. This means that if you apply a voltage of 20 V to the circuit, then the output should be about 500 V. This is not entirely true. Since any impulse transformer source or generator without load has powerful high-voltage impulses, reaching a voltage of 30,000 V! Therefore, if you disassemble any impulse Chinese charging, you will see a soldered resistor parallel to the output capacitor. This is also a load network, without a resistor, the output capacitor will quickly leak due to overvoltage, or worse, it will explode.
Therefore, attention! The voltage at the output of the transformer is life threatening!
Diagram of a mini welding machine
Required details:
- The transformer is homemade, the manufacturing procedure is described below.
- Resistors - 0.5-2 W.
- The transistor was used FP1016 but is hard to find due to its specificity. Can be replaced with a transistor 2SB1587, KT825, KT837, KT835 or KT829 with a change in the polarity of the power supply. Another transistor with a collector current of 7 A or more, a collector-emitter voltage of 150 V or more, with a high gain (composite transistor) is also suitable.
Transformer manufacturing
The transformer is wound on a piece of ferrite rod from a radio receiver.- Collector winding - 20 turns of wire 1 mm.
- Base winding - 5 turns with a reason of 0.5-1 mm.
- High-voltage winding - 500 turns with an occasion of 0.14-0.25 mm.
We collect the scheme. If everything is in order, everything should start without problems. Since the operating frequency of the generator exceeds the audio frequency, you will not hear a squeak during operation, so do not touch the transformer output with your hands.
Start the generator with a voltage of 12 volts and increase if necessary.
The arc is ignited from a distance of 1 cm, which indicates a voltage of 30 kV. The high frequency prevents the burning arc from breaking, as a result of which the arc burns very stably. When using a copper electrode in close contact with another electrode, a plasma medium (copper plasma) is formed, resulting in an increase in the temperature of arc welding-cutting.
Tests of the welding machine by cutting and welding
We cut an arc with a razor blade.
We fuse copper wires up to 1 mm thick.
A thick layer was used as an electrode. copper wire. It is clamped in a wooden match, since dry wood is also a good insulator.
If you like this small welding machine, then you can make it larger and more powerful. But be extremely careful.
Also, to increase power, you can assemble a generator according to a push-pull scheme, and even on field-effect transistors, as here -. In this case, the power will be decent.
Also, do not look at the bright discharges of the arc with the naked eye, use special goggles.
Watch the video of making a welding machine on a blocking generator
How to learn how to cook with electric welding yourself? A similar question may arise in front of many men who love to understand various processes and know how to do construction or repair work with your own hands. The ability to handle a welding machine can be useful when erecting a fence, repairing a balcony, building in a country house, and other household work. Those who have mastered this business especially well can independently weld pipes for supplying water or creating heating system. Create quickly strong connection, better than a weld, will not work. But in order to learn how to weld metal correctly, you need to explore the basics of welding. Understanding the essence of the process of electric arc technology, the stages of work, the position of the electrode and various modes, will help you quickly learn how to weld correctly.
How to learn to cook with electric welding lesson 1
To master this method of joining metal well, it is necessary to understand the physical process of welding. Understanding the formation of a seam will help you cook not “blindly”, but with an awareness of what is happening, which will certainly be reflected in the result.
For welding, various devices are used that convert the current to the desired value, capable of melting steel. The simplest are transformers operating from 220 and 380V. Due to the windings of the coils, they lower the voltage (V) and increase the current (A). Most often these are large devices on industrial enterprises or small homemade apparatus in the garage.
More "advanced" versions are converters that issue constant pressure. Thanks to this, the creation of the weld is more delicate and quieter. At home, small versions of these devices, called inverters, are used. They work from the household network and convert alternating current into permanent. Learning to cook with an inverter is easier than starting with a large industrial transformer. The essence of the process is as follows:
- The device produces the required voltage.
- Two cables (+ and -) come from the inverter, the first is attached to the product, and the second is supplied with an electrode holder. The negative cable is referred to by some as zero. Depending on which wire clings to ground, the polarity of the current is determined.
- At the moment the end of the electrode touches the workpiece, an electric arc is initiated.
- Particles of the molten electrode rod and the edges of the welded metal form a connecting seam.
- The coating on the electrodes, melting, creates a gas cloud that protects against exposure environment weld pool, and providing a connection without pores.
- When the metal solidifies, a layer of slag forms on its surface, which is removed by light tapping.
Any budget model that supports work with electrodes with a diameter of 3 and 4 mm can become an inverter for beginners.
Workplace preparation
How to learn how to cook with electric welding in a short time? You won’t be able to do this in one day, but by applying the tips from a variety of videos and preparing everything you need at the workplace, you can quickly start practicing.
To learn how to cook welding inverter need a plate to ignite the electrode. It is not always possible to attach the mass to the product, so a small metal table or base is required. The welder should have a hammer on hand to correct the fixing of metal parts, a slag separator, and a means to extinguish the fire (sand or a fire extinguisher). Welding metal with an inverter is important, being well protected from harmful influences. Regardless of the place of work (home or production conditions), each welder must have:
- a protective mask with a light filter corresponding to the lighting at the workplace (in filter No. 5 it will be hard to see indoors, in No. 3 it will be very blinding to the eyes on the street);
- canvas mittens to protect against heat and splashes;
- thick, non-flammable clothing not tucked into the belt;
- boots;
- headgear to protect against flying slag drops.
Learning to hold the electrode
To learn how to weld by welding, you must properly hold the electrode. The electric welding process and the final result directly depend on this. It's best to start with 3mm diameter electrodes, which are not as long as 4mm but melt slower than 2mm. For fixing in the holder, a mechanism of two types is used. The first type of fastening is spring, the second - screw. For the first holder, it is necessary to press the key and remove the clamping mechanism. For the second, turn the knob counterclockwise.
When welding, the optimal angle of inclination of the electrode relative to the surface is 45 degrees. So you can lead the seam away from you, towards yourself, from left to right and vice versa. To successfully weld with inverter welding, you must learn to keep a distance of 3-5 mm between the end of the electrode and the metal. This is very difficult at first, and violating this requirement, the electrode will either stick to the product, or move away and spray metal particles. Therefore, the first lessons in electric welding can begin with the machine turned off, in order to practice keeping a distance. A distance of 3-5 mm is easier to maintain if there is support under the elbows of the welder against the legs or the table. A good mastery of this nuance will help in the future to learn how to cook semi-automatically and other types of welding.
Arc ignition tutorial
How to learn how to cook with electric welding can be found in the training video. It all starts with warming up the electrode. To excite electric arc between the mass and the end of the electrode, it is necessary to lightly tap the latter on the surface. It is recommended to do this on a separate plate so as not to leave marks on the product. The heated electrode is brought to the junction, and the arc is excited by the slightest touch with the surface. At first, you can simply burn a couple of electrodes in order for the hand to get used to the distance and stable retention of the arc. This will help to get used to visually, when everything stops sparkling in the mask, and an understanding of the ongoing process comes. To distinguish between molten slag and metal in the weld pool, it is worth remembering that the whitest and brightest light comes from steel, and the reddish one from slag. By learning to distinguish between these components, you can better form seams and notice uncooked places.
Electrode movements
It is impossible to cook with electrodes qualitatively without mastering the technique of movement. How to independently learn how to cook with electric welding and correctly form a seam? The main criterion in understanding the features of technology. Particles from the electrode rod are fused where the end is pointing. Therefore, skillful manipulation of the electrode is the key to a correct structure and a strong seam. In addition to mm iron, most of the welded products are connected by multi-pass layers. This ensures tightness and good properties to break. The first seam is called the root and is carried out exactly, strictly at the junction. This allows the molten metal to fill the gap between the plates. Subsequent layers, having a base under them, are performed with oscillatory movements. It can be any of the manipulations from the list below, moving forward:
- zigzags;
- ovals;
- eights;
- triangles.
Periodically, experienced welders tug the end of the electrode back briefly to drive away a layer of slag that interferes with the observation of the formation of the seam.
Steps to get started with welding
After preparing the workplace and mastering the retention of a stable wire, as well as the practice of suturing the flat surface, you can start connecting the two parts of the plates. This requires:
- Position the product in the correct position.
- Fix the set position with welded tacks, 5 mm long, at least in two places on each side. This is necessary due to the property of the metal to contract and expand from heating. If you start welding parts without tacks, then the other edge of the product may deviate significantly from the required size. Slag is beaten off from the tacks to prevent it from re-melting and getting into the weld pool.
- The arc is ignited and a root suture is applied. The completion of the seam must be done with an overlap of the frozen metal in order to avoid funnels and other defects.
- The slag is beaten off, and the quality of the connection is visually checked.
- A seam is applied on the opposite side to balance the tension.
- Subsequent layers are performed with alternating sides.
- The final version is processed, if necessary, by a grinder, and painted over to prevent corrosion.
Vertical connection
Vertical seams are made a little differently, and their creation should be started only after a good mastering of welding in the lower position. The criterion in this case is an intermittent arc, which ensures the solidification of the superimposed metal and prevents it from falling down. After tacking, transverse movements are made with the end of the electrode, with the arc breaking off after one or two manipulations. The seam is from the bottom up. Welding modes correct mode welding is a prerequisite for good quality work. Here are the main standards.
