How to make spot welding from a microwave transformer

Microwave spot welding

A small welding machine is always useful on the farm. A model capable of resistance welding will be very helpful in making fence mesh and creating cages for breeding birds and small animals. Such a device can even connect rods under the greenhouse frame. But store-bought versions are quite expensive.

Therefore, spot welding from the microwave can be an excellent solution to the situation. To do this, it is necessary to select and remake the transformer, correctly create working levers, and make a safe housing. Several videos from the Internet will complement the general instructions for making spot welding from a microwave transformer.

Details and essence of the process

DIY spot welding must meet certain standards to be able to fulfill its intended purpose. The essence of the process is identical to how the spotter works. The completed device receives power from a regular 220V network. The converted transformer lowers the voltage (V) to a safe value (12V), and raises the current (A) to a value capable of heating the metal to the melting point.

The converted current is supplied to the capacitors for charging. After the accumulation of electricity, the relay transfers the voltage towards the working contacts. The workpiece to be welded is placed between two copper electrodes, the closure of which leads to the passage of a powerful pulse, creating a molten point in the contact zone.

The temporal length of the pulse varies from 0.01 to 0.1 s. After cooling, a point connection is formed. And the capacitor begins to charge again for the next cycle.

A similar diagram of resistance welding with your own hands from a microwave conveys the general essence of the operation of the device, but can have various variations, depending on the required power of the device.

To create a microwave spot welder with your own hands, you will need the following parts:

converted transformer;
button;
terminals;
two light diodes;
automatic 20 A;
relay REK 74;
two copper rods with a diameter of 5 mm;
diode bridge and a set of capacitors;
PC fan.

Working with a transformer

The SV oven contains a transformer that is suitable for converting the current to the required strength and magnitude. How to make it suitable for welding is shown in many videos. It is necessary to remove the secondary winding from the microwave transformer. This can be done with a hacksaw or a chisel. When reaching the edge of the winding, you should be careful not to damage the insulation of the primary coil with your actions.

Having cut off the edges of the winding on the sides, they begin to remove the inner part. To do this, I use a drill and a drill with a diameter of 5-6 mm. After making a few holes, the rest of the winding can be removed by hand.

Homemade spot welding requires proper construction of the transformer secondary coil. A cable with a diameter of 10 mm or more is suitable for this. This can be either a stranded wire in general insulation, or a bundle of individual wires assembled together and corresponding to the required diameter. Winding is done in three turns around the core. Such a transformer will be capable of delivering a current of more than 800A.

Since space inside the transformer core is limited, some people have difficulty routing the cable. You can make your work easier by lubricating the wire with oil or grease. An alternative is to remove the factory insulation and apply thin rag tape. The length of the wire should be minimal, sufficient only for winding and leading to the working parts. Unreasonable extension will create unnecessary resistance.

This resistance welding from a microwave can weld:

grids;
cells;
rods up to 3 mm;
metal plates up to 3 mm.

To work with thick iron, it is possible to increase the power of the device by using two similar transformers from a microwave oven in its circuit. Serial connection of the terminals of the primary and secondary windings will double the output current and bring this figure closer to 2000A. With this current you can cook thicker iron. Manufacturing devices with even higher performance, intended for use at home, is impractical due to the increased load on the network.

Manufacturing of electrodes

Spot welding is performed by directly connecting two electrodes. The material of the latter should be copper. The diameter of the working rod must correspond to the cross-section of the cable connected to it. You can use a regular copper rod. For welding thin wires, a soldering iron tip of two pieces is suitable.

During the welding process, the electrodes are constantly overheated and the shape of their ends requires periodic editing. To do this, the electrodes must be removable. Their fixation is carried out by crimping using a bolted connection.

Over time, they will have to be replaced. It is better to make all other connections solid, since additional resistance will be created at each connector.

To do this, the end of the secondary winding cable can be equipped with a special terminal secured by soldering.

Creating a working part

To perform resistance welding on a homemade microwave machine, you need a working part of the device that allows you to quickly connect the electrodes and clamp the product between them. You can use a profile, rod or wooden beam as the lower base. One end of it is attached to the body with self-tapping screws for rigid fixation. The bottom electrode is connected to the second edge, to which the cable from the transformer is supplied. To prevent the wire from dangling, it should be tied to the rod.

The top part must be movable. This will be a lever. A long nail can act as an axis, and the racks on the sides are made of two bars or profiles.

It is advisable not to leave gaps between the posts and the base of the lever, otherwise this will reduce the accuracy of matching of the upper and lower parts, which will affect the accuracy of welding.

When not in use, the lever automatically moves upward to prevent accidental closing of contacts and unhindered access to the device. To do this, a spring from the carburetor of sufficient rigidity is attached to its base. Methods for such fastening are on video on the Internet.

The shorter the lever, the harder you will have to squeeze it with your hands. Therefore, the optimal length that creates the required load during welding will be from 500 mm. At the upper end of the lever there is a button that starts the discharge of the welding pulse. The cable and wires are also fixed to the working part to prevent breaks and snags on the product. For ease of pressing, you should attach a soldering iron handle to the upper lever.

Homemade spot welding machines have simple housings. Most are made exclusively from wood. This requires:

base (board 10-20 mm);
side walls;
corners and screws;
top cover.

It is necessary to make a hole in the side wall for the outlet of the power wire. The front part is not closed, since working pliers and cables are routed through it. It is worth screwing a thick tape into the top cover to carry the device.

There are no ventilation holes, but a computer cooler is inserted into the back wall of the device, which provides the necessary cooling. The absence of a front wall where the working jaws are removed, and a fan in the rear, cool the air and parts inside well.

Schemes of homemade spot welding machines and videos on how to create them on the Internet help to make a device that serves as a good help in the household and is much more economical in cost than store-bought versions.

Source: https://svarkalegko.com/oborudovanie/tochechnaya-svarka-iz-mikrovolnovki-svoimi-rukami.html

How to make spot welding from a microwave or battery with your own hands

Arc welding machines are used in everyday life. Such devices are easy to find on the open market, and they have a relatively low cost. However, situations arise when resistance welding may be necessary. This device has a fairly high cost, and its purchase may not be profitable. To save money, spot welding is done by hand.

Features and principle of operation

Spot welding works using a powerful short-term electrical pulse supplied to the electrodes from an inverter. The parts are heated to their melting temperature, then they are connected to each other. At the junction site, a strong weld remains between the two electrodes. The peculiarity of the work is that the place of spot welding is limited by the diameter of the electrode used.

Before combining the two metal parts, they are pressed tightly against each other. After resistance welding, they need to be kept under pressure.

Spot welding allows you to weld metal in small areas of a car body during body work, solder wires and small parts together, and repair electronics.

How to make spot welding with your own hands from a microwave

A mini resistance welding machine is made with your own hands from some microwave spare parts. For a homemade unit you will need to remove the following components:

Transformer.
Switch.
Power cord.

Removing the transformer

The separation of the transformer from the microwave is carried out according to the following algorithm:

The microwave oven is disassembled.
All fastenings are removed.
The transformer is removed from its seat.
The microwave parts necessary to create a device for spot welding are dismantled.

The extracted transformer has a power of 700-800 watts. This is enough to ensure the connection of metal sheets up to 1 millimeter thick. To manufacture a more powerful spot welding machine, this part is being modernized.

On a transformer, the primary and secondary windings differ in thickness and number of turns. The secondary winding is removed from the part using a chisel and hammer. In this case, all operations are carried out carefully, otherwise the magnetic circuit may be damaged. In this case, the transformer will be damaged.

Instead of the dismantled winding, use a wire whose thickness is at least 1 cm. 2-3 turns need to be wound around the core. This simple upgrade allows you to increase the output voltage to 1000 A.

For a spot welder with increased power, two connected modernized transformers are used.

Transformer Upgrades

When creating spot welding from a microwave, it is necessary to upgrade the welding transformer:

When dismantling the secondary winding, limiting shunts can be found. They are also removed.
The fewer turns of the new secondary winding are created, the lower the resistance of the wire will be, and the greater the current. The cable should not be excessively long.
When winding a new secondary winding wire, difficulties may arise due to the thick insulation. Care should be taken to replace the standard rubberized insulating layer with electrical tape that has a fabric backing. Such a wire should provide an output voltage of 2V and a short-term current of 800A.
The performance of the point device depends on the correct connection of the two transformers. The elements are connected in a circuit. It is necessary to correctly connect the primary and secondary windings of the transformers. This can be done using special markings. If they are missing, then measurements must be taken using a voltmeter.
The design of a spot welding machine used in home workshops involves the creation of a device with a power of no more than 2000A. Otherwise, there will be a load on the home network, which will lead to power outages. This circuit also involves checking the current strength and the presence of short circuits using an ammeter.

After creating the electrical part, install the grounding and switch of the spot welding machine. The part is taken from the microwave. Next, the body, levers, holders and electrodes are made.

Creation of electrodes

Electrodes for spot welding are involved in the supply of current, perform a pressing function and remove excess heat. To create these components, copper is used; this material is resistant to mechanical and chemical influences (the base metal contains impurities in the form of 0.7% chromium and 0.4% zinc). From various videos on the Internet, you can get detailed information about metals suitable for creating electrodes.

Pliers for welded materials vary depending on the type of metal being processed. Thus, tips made of copper plates and having a flat working surface are suitable for connecting ordinary steels. Resistance welding of aluminum, copper, and high-carbon alloy steels is performed using electrodes with a spherical working surface. To make connections in hard-to-reach places, shaped electrodes are used.

The electrodes must be tightly fixed to the holder. To do this, the landing parts are given a cone shape, and some are threaded.

The diameter of the electrode must be at least twice the thickness of the parts being joined.

Making the holder

A homemade spot welding machine is equipped with control levers. They can be made from high-strength plastic or wood. To lift the levers, use a regular rubber band; fasteners for electrodes are installed at the ends of the parts. The holders are not screwed to the device, and this is due to the fact that in some cases, to perform contact welding, you will need to use each element separately. The levers are fixed with a screwdriver or nail.

Battery spot welding

When creating spot welding, car batteries are also used. This device is used when soldering batteries and connecting small parts when repairing electronics. The design of the resistance welding machine consists of a power source, a relay, a special block and two copper wires. The working ends of the wires are stripped and act as electrodes.

Electronic repairs and complex body work involve the use of spot welding. The welding seam is strong, and the small working area allows resistance welding of small parts.

However, a serial resistance welding machine is quite expensive. It is cost-effective to create spot welding from a microwave or welding machine with your own hands.

If you follow all the nuances of design and safety precautions, you will get a functional device capable of fastening sheets of metal up to 5 millimeters thick.

Source: https://InfoKuzov.ru/material-instrument/kak-sdelat-kontaktnuyu-svarku

DIY microwave welding

After watching interesting videos on, and also being inspired by this topic on ChipMaker, I also really wanted to make spot welding from a microwave with my own hands.

To make welding from a microwave, I purchased a transformer from a microwave, a 50 sq. mm stranded copper wire. about 2 m long, but this turned out to be a lot. As electrodes for spot welding, I used tips from soldering irons with a diameter of 13 mm; I could not get another copper rod in my city.

So, how I made spot welding from a microwave transformer.

How to make a transformer

First I sawed the transformer to remove the secondary winding, and I will repeat again:

Please note that a microwave transformer is dangerous to life! Those. it should not be connected to the network for testing until the secondary winding is removed, because The voltage on it is about 2000V and it can kill a person from a distance!

From copper wire to 50 kV. mm I removed the insulation because... it is too thick and is designed for 600 volts, and spot welding has a voltage of 2-3 volts in total.

As experienced people joke: Papyrus is enough for insulation

Source: https://evmaster.net/tochechnaya-svarka

Homemade spot welding machine from a microwave

Translated by Creator for mozgochiny.ru

In this brain project, I want to tell you how to make a resistive spot welding machine with your own hands I plan to use it to weld nickel plates to an 18650 battery, but depending on the position of the electrode holder, the machine can be used to weld sheet metal and other metal objects. Now let's start making the device!

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Step 1: Disassembling the microwave

Warning!
There is a danger inside the microwave oven. A large capacitor may be charged and is a potential source of dangerous or fatal electrical shock. Therefore, you should discharge it as quickly as possible by short-circuiting the capacitor terminals using the metal blade of a screwdriver.

So, remove the microwave cover to get to the electronic components of the device. Discharge the capacitor as stated earlier and begin dismantling the microwave parts. Find a transformer that should look something like the one shown in the photo. Unscrew the nuts and it should come out quite easily. I also removed some limit switches that will be used later and some power cables.

Step 2: Removing the Secondary Winding

It is necessary to rewind the secondary winding if we need to get more current and less voltage. The primary winding is where the power is supplied and the secondary has a thinner winding wire with red wires attached.

Fewer turns of wire increases the current but decreases the voltage, and more turns increases the voltage but decreases the current. We do not need the secondary winding of the transformer, so it must be carefully removed. Be careful not to damage the primary winding.

Step 3: Adding a New Winding

The new winding will provide the necessary current for the operation of our welding machine. Choosing a thick cable will allow you to reduce the number of turns from thousands to just a few and still provide the required current load. A thick cable has good insulation, which will not melt when heated, as in a thin cable.

First install the primary winding, followed by 2 shunts on each side and then wrap a couple of turns of blue cable on top. Be sure to leave enough cable length to attach the welding electrodes.

Step 4: Completing the Transformer Fabrication

Our super powerful transformer is almost ready. The top part needs to be welded back. Alternatively, you can use a 2-part epoxy to glue it in place. There is a choice, use the method that suits you best!

Step 5: Electrode Leads

Now we need to attach the ends of the cable to the copper bushings that will be used for welding. I turned the copper bushings on a lathe. But you can use copper clamps from a hardware store for this purpose. I have also attached a CAD file for making the electrode clamp.

Step 6: Welding Holder

I will use a welder to weld the nickel plates to the battery. For this purpose, I will place two welding electrodes side by side, although you can easily place them opposite, like in a traditional welder. I designed and laser cut a fiberboard base for the holder that will hold the switch and electrode leads.

Step 7: Completing the Project

The transformer is supplied with a dangerous voltage of 230 V, so it is very important to close the transformer. A laser cut enclosure can be perfect for this purpose. Make sure all live parts are covered. This will ensure your safety when working with the device.

To connect the phase and neutral to the primary winding of the transformer, use the existing contact plates. I recommend installing a switch between one of the power cables to easily turn the device on and off. I used the switch from the microwave.

Your device is now ready. Time to start spot welding !

(Az Source)

Source: http://mozgochiny.ru/instrumentyi-diy/samodelnyiy-apparat-dlya-tochechnoy-svarki-iz-mikrovolnovki/

Do-it-yourself spot welding from a microwave diagram and description

Today I would like to tell you how to do spot welding with your own hands from a microwave. This device is capable of producing 800 A output, and this indicator is enough to weld thin (1 to 1.5 mm) sheet metal.

We disassemble the microwave and remake the transformer

First, let's take a microwave. Inside this device there is a transformer, which consists of a core and two windings: primary and secondary.

The transformer core is sealed with two thin welds as shown in the picture.

To open the seam, you will have to use a grinder or a hacksaw, and to get to the windings in the transformer, you will need to work with a hammer and chisel.

When removing the primary winding, you should be extremely careful not to damage it, because we will use it in the future.

The winding of the secondary winding is usually very tight, so it is difficult to remove. Since it is not useful for the welding machine, it can be sawed and pulled out in parts.

After completing the described actions, you should have at your disposal a whole and undamaged primary winding of the transformer and its core, divided into two pieces.

Winding the transformer

The next step is to wind the secondary winding of the transformer. We will use a copper cable as the material for the secondary winding, the thickness of which will be approximately equal to the slots of the core. The cable is wound in two turns.

After winding the cable, you need to glue the transformer core and base. To do this, we use regular 2-component epoxy resin.

When the epoxy dries, the transformer should look something like this.

The output voltage in the transformer is 2 V, however, the current is 800 A.

Let's check the performance of spot welding:

Spot welding body

After this, we should start making a case for our device. It could even be made of wood.

The rear panel of the case must be equipped with a switch and a power cord, for which a couple of holes should be cut.

The next stage is sanding, priming and painting all parts

When the painted body has dried, we should finally assemble our device.

You should cut two copper wires, approximately 2.5 cm in length, they will serve as electrodes, and clamp them in the holders.

After this, we install the power cable switch to the rear panel of the device.

We mount the transformer on a wooden base using ordinary self-tapping screws. One of these self-tapping screws is used to secure the terminal from which the “ground” is output.

The electrical component of the device is now complete, however, to ensure greater safety and convenience, we will install another button (microphone), which is attached to the upper arm with a slight slope. This is done to ensure that spot welding only works when the switch is on and the microphone is pressed.

Don't forget to carefully insulate all connections!

The levers are fastened like this: the levers are placed one on top of the other, and holes for them are drilled in the sides, into which ordinary nails are inserted, the tips of which are bent.

Installation of contact electrodes is carried out from the ends of the levers.

A regular rubber band is used to secure the upper arm.

Spot welding tests:

Replacing welding electrodes:

Do-it-yourself spot welding from the microwave

Source: http://postroyka-dom.com/tochechnaya-svarka-svoimi-rukami-iz-mikrovolnovki-shema-i-opisanie/

DIY spot welding from the microwave! | Master Vintik. Everything with your own hands!

Previously we wrote: what can be done from an old microwave oven. Today, let's take a closer look at how to make a spot welding machine with your own hands from a high-voltage transformer or MOT (Microwave Oven Transformer - microwave oven transformer) from an old, unusable microwave oven. Of course, provided that the high-voltage transformer is working (at least its primary winding), and something else is faulty: magnetron, cable, control board, etc.

For a master, there is a need for spot welding. This spot welding produces a current of up to 800 Amperes, which is quite enough for welding sheet metal up to 1.5 mm.

So, we need an old microwave and the larger it is, the better. Larger microwaves have a higher power transformer. If you don’t have an unnecessary microwave, you can often buy old microwaves cheaply on forums and free bulletin boards, or you can look for them near trash containers or ask at TV repair shops.

Attention! Before disassembling, the microwave must be turned off from the power supply. Next, we disassemble the microwave oven. There are several components inside a microwave oven that are dangerous even when turned off and can cause serious electric shock - these are capacitors (see photo) that can hold a charge for some time. Therefore, we discharge the capacitors by connecting their terminals to each other with a screwdriver. The high voltage transformer is located below.

Of the insides of the microwave, we are primarily interested in the high-voltage transformer.

The transformer consists of a core and two windings: primary and secondary. The primary winding is wound with thicker wire and contains much fewer turns.

The transformer core is held together using two thin welds, as seen in the photo.

How to make a transformer for welding?

There are two options for removing the winding:

Disassemble the transformer core.
Cut off the winding with a chisel.

Method 1.

You will need a hacksaw or grinder to cut this seam, as well as a hammer and chisel to get to the transformer windings.

Be careful when removing the primary winding from the transformer, as we will need it later.

Try not to bend or scratch it.

The secondary winding can be wound very tightly and is difficult to remove, so if you don’t need it, you can cut it and pull it out in pieces, it will be much easier.

Now, after all the manipulations, you should have in your hands an intact and undamaged primary winding of the transformer and its core, divided into two parts (without glue and paper that held its windings inside).

The next step is to wind the secondary winding of the transformer. To do this, you need to take a copper (required!) cable of approximately the same cross-section as the slots in the transformer core (about 7 mm) and wind two turns.

I then bonded the transformer core to its base using regular 2-part epoxy resin and gently pressing it in a vice and left it to glue.

Once the epoxy has dried, the transformer should look something like this.

Method 2.

It’s also not easy, but the transformer hardware will remain intact, which is important. To do this, you need to remove the winding using a chisel, chisel, hacksaw, etc.

We also remove shunts.

Next, we wind a new winding onto the transformer. It is made from stranded wire with a cross-section of at least 100 mm2 (or a diameter of more than 1 cm). It will be enough to make 2-3 turns. If the wire has too thick insulation, you can remove it and replace it with fabric insulating tape. If two transformers are used at once, then the secondary winding for them is made common, but it is very important to correctly connect the leads from their primary windings.

The voltage at the output of the transformer was just over 2 volts, but the current was about 800 Amperes! This is sufficient current to ensure a strong connection when welding metals.

DIY welding body

Now all that remains is to make a housing for the spot welding machine. You can make it out of metal.

You can make the body out of wood. You can make it based on what you have on hand.

The photo below shows the process of making the case.

Once I had all the body pieces cut out, I carefully rounded the edges using a router bit. You will need to make a notch on the upper arm so that the arm can easily rise up without resting on the body.

On the back panel I cut two holes, one for the switch, the second for the power wire.

I then attached the switch to the back panel and inserted the power cable into the hole. The thickening on the cable prevents it from falling out.

I secured the transformer to a wooden base using regular self-tapping screws. I put a terminal on one of them, which I connected to ground.

I then sanded, primed and painted all the parts. I chose two colors - black for the body, and yellow for the moving parts (levers).

Also, when making spot welding with my own hands, I used:

Power cable;
Door handle;
Switch;
Copper holders for contact electrodes (2 pcs) (they can be bought in stores selling welding equipment);
Thick single-core copper wire for making contact electrodes (about 5 mm);
Wood screws, nails;

After the painted body had dried (I gave it about 2 days), we began the final assembly of the device.

Electrodes for spot welding

The electrodes of equipment for spot welding perform several functions simultaneously: compression of the sheets being joined, supply of current to the welding zone, and subsequent heat removal. Important parameters when choosing an electrode are its shape, dimensions, etc.

It is these parameters that directly determine how high quality the welded joint will be.

The geometric shape of the electrodes can be straight or curly, but preference is given to straight models, as they provide better access to the welding area.

When choosing electrodes for a microwave welding machine, you can simply refer to the corresponding GOST (14111-90), which already specifies all possible diameters of these elements (10, 13, 16, 20, 25, 32, 40 mm).

Homemade electrodes. To make them, cut two pieces of thick copper wire, each about 2.5 cm long. Clamp them into the holders. The electrodes in the holders are tightened using a regular screwdriver. The denser the better.

The electrical part could be considered complete, but for greater safety and convenience, I decided to add another button (microphone), which will be located on the upper lever at a slight angle. Microswitches can also be taken from the microwave. This way, spot welding will only work when the rear panel switch is on and the mic is pressed (in other words, two switches are in series).

You can use a timer to set the welding time. For example:

Note: Remember to carefully insulate all connections!
I screwed the sides with self-tapping screws (6 pieces per side).

I secured the levers in the following way: experimentally (by eye) I installed them one on top of the other, drilled two holes in the side walls (for the lower and upper levers) and inserted an ordinary nail into the hole, the end of which I then bent. The result is a cheap and reliable axle.

I installed contact electrodes at the ends of the levers. For convenience, the top wire goes in one direction, the bottom in the other.

After the contact electrodes burn out, they can be easily removed and replaced with new ones.

To ensure that the upper arm was always raised, I used a regular rubber band.

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If, after assembly, the axes of the electrodes do not align correctly with each other, this can be easily corrected by bending them slightly.

Homemade spot welding tests

To use, place thin sheets of metal between the electrodes, then press the button (micric) for 3-4 seconds. A powerful pulse of electric current heats them to the melting point, and the pressure of the electrodes further strengthens the welded joint.

Now you can remove your finger from the button and wait until the weld has cooled down.

The DIY spot welder works so well that after welding these washers together, I could not separate them (I was only able to do this using 2 pairs of pliers).

Attention!

1. You cannot short-circuit the electrodes with each other!

2. When welding galvanized metals, zinc oxide fumes are formed, which is harmful. Therefore, it is advisable to carry out welding work in a well-ventilated area.

the process of making a spot welding machine with your own hands:
Another option for spot welding:

Another option for making spot welding:

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Source: http://www.MasterVintik.ru/tochechnaya-svarka-svoimi-rukami-iz-mikrovolnovki/

How to make your own spot welding from a microwave transformer

The topic of the article is for handy craftsmen, spot welding - we make the device with our own hands from improvised means. And a used microwave oven will help us with this. Or rather, a high-voltage transformer from it, which is suitable for connecting thin sheet metal at home.

Just don’t have to run headlong into the kitchen to disassemble your microwave. You can ask your neighbors for experimental material, find it at a landfill, or buy it second-hand for cheap.

How to mount a transformer correctly

So, we make spot welding with our own hands from the microwave. We need a transformer that consists of a welded core and primary and secondary windings.

We take it out of the old cracked oven. The desired transformer power is from 800 watts, the more powerful the better.

We will need a core and a primary winding (with a thicker wire). We remove the secondary winding, for example, cut it off with a chisel or saw it with suitable tools.

Sometimes, in the case of a tight fit of the secondary winding, in order to remove it, you have to disassemble the core and then glue it together.

After removing unnecessary junk, we take a copper cable (with a cross-section of 16mm2, determined experimentally) and wind 2 turns in the transformer windows.

We securely attach copper lugs to the ends of the cable.

So, the main part for homemade spot welding from the microwave is ready. We are thinking about the design of the future structure.

Appearance of the device

If the head works and the arms grow correctly, then the entire structure can be made of metal (reliably and beautifully). Let's look at a complex circuit first.

Internal structure of the device:

transformer from a microwave with a wound copper wire;
terminals for copper wire;
20 ampere circuit breaker for de-energizing the network;
terminal block for connecting wires;
computer fan with 12 volt transformer;
diode bridge with capacitor;
relay REK 74;
2 indicator lights;
microwave button.

External microwave spot welding design:

base with side walls;
closing lid with handle;
corners with bolts;
2 pieces of profile for pliers;
soldering iron handle mounted on a hexagon while hot;
spring from carburetor;
electrodes are attached to the corners.

The angles allow you to change the angle of the electrodes for precise contact. Electrodes can be made from a soldering iron tip with sharp or blunt tips; in the case of welding different materials, it will be possible to change them. At the attachment point, the electrode rod is thinner with a thread cut for the nut.

Watch the video to learn how to make this type of spot welding yourself.

I understand that not everyone will make such a design. Therefore, we will consider simpler options for a do-it-yourself spot welding machine.

Simple welding machine body

A wooden structure is the simplest design that anyone can make. The photo below shows design ideas.

Let's take the last option as a basis: take a tape measure and take the dimensions of the prepared microwave transformer. Based on the measurements taken and our idea, we prepare wooden blanks for the device.

We make the upper lever (do-it-yourself spot welding pliers) with a recess. This is if you make a device with a closing lid. If the device is planned to be open, then a recess is not needed.

On the back wall we cut out suitable holes for the power button and wiring.

For beauty lovers: the blanks for the device can be painted in your favorite color.

Also, for do-it-yourself spot welding you will need the following materials:

switch;
handle for closed structure;
circuit breaker (micrik);
power cord.

Take these accessories from the disassembled microwave.

Also needed:

electrodes can be made from a soldering iron tip or thick copper wire;
copper holders for attaching electrodes (you will have to buy);
self-tapping screws for assembling the structure.

We insert the prepared electrodes into the holders and clamp them with a screwdriver.

We secure the back wall with the screwed switch and power cord to the main board with self-tapping screws.

We also attach the microwave transformer with self-tapping screws to the base of the device. We screw one of the screws with a grounding wire, which we connect to the switch.

Also, we run a wire from the switch to the transformer, and we lead the second wire from the transformer to the circuit breaker, which we borrowed from the microwave.

You can do without a circuit breaker installed in series in the electrical circuit. It serves for convenience and is installed on the upper arm of the spot welding machine.

Using wooden blanks and self-tapping screws, we close the electrical part. The top board must have a handle for carrying the device.

Device levers

Next, we think over the design and attach the levers (pliers) for spot welding with our own hands. First, we drill holes for self-tapping screws at the ends.

We attach the electrical circuit breaker to the upper lever with a convenient slope.

We insert the pliers into the device and determine the attachment location by eye. We drill through holes in the side walls and levers, and secure them using metal rods.

Using self-tapping screws, we attach the holders with contact electrodes to the end part of the pliers.

After assembly, the electrodes usually face in different directions; we bend them with our hands to center them.

To raise the upper arm, we screw it into it and into the body of the device using a self-tapping screw, not completely, and attach a spring or a tight rubber band to them.

Trying a welding unit

Our spot welding is ready, we are testing the machine. Turn on the power and press the breaker with your thumb.

Sparking appears between the electrodes, but this cannot be done.

Thin sheets of metal can now be reliably joined with our device. If you have a vehicle, then homemade spot welding for welding a car will make it easier to repair the body.

To do this, we made the levers removable; just pull out the metal rods and remove the pliers to weld large-sized metal and you can crawl into hard-to-reach places.

Also, there is a plus in removable electrodes, which are easy to replace if necessary.

will tell you about the correct winding of a transformer and show the entire process of assembling a resistance welding machine.

Source: https://plavitmetall.ru/svarka/tochechnaya-apparat-svoimi-rukami.html

Spot welding of two transformers from a microwave oven

From 2 transformers from an old microwave oven, you can make a useful device for your home workshop and garage with your own hands - resistance spot welding.

Resistance spot welding makes it possible to work with a wide variety of metals and their alloys, which makes it universal for everyday use.

First of all, we remove the transformers from the microwave body. After this, you will need to carefully remove the “native” secondary winding without damaging the primary.

The easiest way to “painlessly” remove the secondary winding is to cut off the protruding turns with a grinder.

After this, using an electric drill, you need to drill a hole inside the transformer and pull the remaining wires out with narrow-nose pliers.

Main stages of work

After we have removed the secondary winding from the transformer, we remove everything unnecessary, including metal spacers. Only the secondary winding should remain.

The same operation will need to be done with the second transformer. Then the master welds both transformers together.

Instead of a secondary winding on two transformers, the author uses a thick multi-core cable, which is intended for a welding machine. It is enough to make only two turns. The secondary windings are connected in parallel.

A piece of channel 160 mm wide is used as the base. You need to drill a couple of holes with a diameter of 8 mm in it, then screw on the perforated profile. You also need to weld two corners with holes to the channel.

Next, we cut off another piece of the perforated profile and weld a sleeve to it. Then we attach it between two corners. The author installs a spring between the profiles.

Spot Welding Assembly

Four holes must be drilled in the base. Then we install the transformers, having previously connected two primary windings in parallel. We do everything the same as with secondary ones.

You need to glue a wooden cube or block to the upper transformer, to which we screw the switch. The power supply wire will be connected to it.

At the last stage, all that remains is to sharpen the ends of the copper bolts, giving them a conical shape. The bolts are inserted into the holes of the aluminum cable lugs and fixed on the inside of the perforated profiles.

For details on how to make resistance spot welding with your own hands from two transformers from an old microwave, watch the video on our website.

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Source: https://sdelairukami.ru/tochechnaya-svarka-iz-dvuh-transformatorov-ot-mikrovolnovki/

Spot welding machine from a conventional microwave oven

When performing various repair work, sometimes it becomes necessary to securely fasten thin metal sheets or their fragments together. The ideal option in this case is the use of electric resistance spot welding.

Unlike devices designed for manual electric arc welding, which have long become common attributes of home workshops, devices for resistance spot welding are much less common.

Simple scheme

What to do if there is no machine for resistance spot welding? The work needs to be done, and the use of other technologies seems less desirable.

Of course, a spot welding device can be purchased at a store or rented. For those who are used to doing everything with their own hands, and at the same time are not averse to significantly saving money, homemade spot welding is quite accessible for manufacturing.

The layout of a spot welding machine is very simple. The basis of the device is a power step-down transformer, the primary winding of which is designed to be connected to a 220-volt power supply network.

The secondary winding must be made of a large-section wire or busbar, since the short-term current value during contact welding can reach 1000 amperes or more. The number of turns of the secondary winding is selected so that the open circuit voltage of the transformer is 2 - 4 volts .

To carry out spot welding, the power of the transformer must be at least 700 watts. This is a fairly powerful device that has a high cost. It turns out that there is a way out of this situation. Transformers with a power suitable for spot welding are installed in conventional microwave ovens.

The transformer in the microwave serves as a power source for the magnetron circuits and has three windings. The primary winding is connected to a 220 volt network.

The secondary step-up winding creates a voltage of about 4 kilovolts and powers the anode circuits of the magnetron, the secondary step-down winding, consisting of only a few turns, powers the magnetron filament circuits.

Determination of unnecessary winding

Microwaves rarely fail due to transformer-related reasons. In those cases when the malfunction of the microwave lies in the transformer, most often the high-voltage coil is damaged.

And since, as will be shown below, in order to make welding from a microwave, you only need a steel core (magnetic core) and a primary winding, then almost any non-working microwave oven (aka microwave) can serve as a source of the necessary part for spot welding.

Now you need to modify the obtained microwave transformer with your own hands. First, determine which coil will be needed to make spot welding, and which should be removed.

The magnetic core of the microwave transformer is W-shaped, the windings are located on the middle rod, one above the other. The required primary winding is easy to find - it is wound with the thickest wire.

The secondary high-voltage winding of the microwave transformer is made of thinner wire and has many more turns. This winding, as well as the one that consists of several turns and feeds the filament, should be removed.

How to dismantle

You can remove unnecessary parts in two ways:

disassemble the magnetic circuit, remove the coil with unnecessary windings from the middle rod and reassemble the magnetic circuit;
cut off the protruding part of the excess windings, then remove their remains.

The assembly of steel cores of microwave oven transformers at the factory is carried out by welding a set of rectangular plates to a set of W-shaped plates after installing the coils with windings.

To disassemble the core, you need to carefully grind off the outer part of the weld on one side using a grinder. Insert a thin chisel or screwdriver into the resulting gap, lightly tap the hammer to widen the opening and lift the core rod with your hands.

After this, access to the windings opens. We take out the unnecessary coils and install the rod in place. If there is no welding, it can be secured with epoxy glue.

The second method allows you to do the job more accurately. It is best to use a hand hacksaw for metal. Having positioned its blade parallel to the core plates, and stepping back 1 - 2 millimeters from them, you need to cut out the secondary winding of the transformer, while being careful not to damage the core itself and the primary winding.

Once the cut has been made to the end, the remaining winding can be removed. This method allows you to leave the welded joint of the core intact.

Having removed the high-voltage and filament windings, you should also remove the magnetic shunts located between the coils of the primary and secondary windings.

They are a set of steel plates wrapped in paper. They are not required for the operation of the spot welding machine.

Manufacturing of the secondary winding

Now the microwave transformer for spot welding is almost ready, all that remains is to make the secondary winding. A copper stranded conductor with a large cross-section, for example, a piece of welding cable, is suitable for this purpose.

The main thing is that the selected cable passes through the window of the magnetic circuit. Wind two turns with the selected conductor at the site of the removed secondary winding. Now you can carry out the first test of a DIY microwave transformer for spot welding.

The ends of the cable are stripped of insulation. Following safety rules, connect the microwave transformer to a 220 volt network. Using a voltmeter, measure the voltage at the secondary terminals (that is, at the terminals of the welding cable).

If the voltage is between 2 and 4 volts, everything is fine. After this, the operation of the transformer is checked in spot welding mode, that is, in short circuit mode.

To test the operating current of the future spot welding machine from a microwave transformer, the stripped ends of the welding cable are securely connected to each other using a bolted connection.

Cover the secondary conductor with current clamps and briefly turn on the transformer. The current clamp indicator monitors the value of the short circuit current. If its value is about 500 amperes or higher, then everything is done correctly.

Assembling the device

In order for a spot welding machine made from a microwave to be used, it must be equipped with a lever for clamping workpieces, contact spot electrodes and a switch.

The lever, which provides point compression of the workpieces, as well as the housing for the transformer, can be made of wood. At the ends of the lever arms there are electrodes made of thick copper rods. The welding cable leads are connected to the reliable bolted electrodes. The switch is located in a convenient, easily accessible place.

Now your DIY microwave spot welding is ready to go. The workpieces to be welded are placed between the electrodes, clamped with a lever and the current is turned on. This is how welding occurs.

Source: https://svaring.com/welding/apparaty/tochechnaja-svarka-iz-mikrovolnovki-svoimi-rukami

Do-it-yourself spot welding from a microwave

Surely, those who are interested in welding have seen more than once how a spot welding machine works. With it you can make a lot of useful things for the home, and also easily work with thin metal.

The cost of a factory-made spot welding machine is quite high, about 10 thousand rubles or more. However, if you have an old microwave, you can make such a device at home. All that is required of it is a transformer, which is subject to slight alteration.

In this article from the website mmasvarka.ru, let's look at how you can make spot welding from a microwave with your own hands.

Disassembling a microwave oven for refurbishment

To assemble a spot welding machine, you can use almost any microwave, even if it’s not working. However, the transformer from the microwave must be working, since it is this that will need to be subjected to major changes.

First you need to disassemble the microwave body and get to its internal elements. Inside the device there is a textolite board with a transformer; it is this that will need to be removed from the microwave. Next, you will need to unsolder the transformer and after that, you can begin to remake it.

How to convert a microwave transformer for spot welding

The microwave has a step-up transformer that is capable of delivering 2,500 volts from 220 volts. It is from this high voltage that the magnetron of a microwave oven is powered. For this purpose, the secondary winding of the transformer is made with a large number of turns of thin copper wire; in the manufacture of a spot welding machine, all this is not needed.

Therefore, it will be necessary to remove the secondary winding from the transformer, so as not to damage the primary winding. The complexity of its dismantling depends on the design of the transformer, so you may need a hacksaw, a small chisel and a hammer. It is very important not to damage the primary winding.

The next step in converting the transformer, after the secondary winding is removed, is to wind a new winding, but only with a different wire. For these purposes, you will need a thick copper cable with a cross-section of at least 100 square meters. mm. It is with this wire that you need to wind on top of the primary transformer winding, the secondary winding, at least 3 turns, laid tightly to each other.

After the transformer is rebuilt, the process of making microwave spot welding is still not complete. Now you will need to make electrodes and a machine for ease of welding. To make electrodes, you should take small copper rods, which will be used for spot welding. The rods must be attached to the machine through insulators.

To make electrode holders, you should use two pieces of profile pipe, which are connected to each other by a small canopy. At one end of the holders, electrodes are attached to the pipes, and at the other, a previously converted transformer.

Spot welding is a very useful device for the home, which will definitely come in handy when working with thin metal and products made from it.

Source: https://mmasvarka.ru/tochechnaya-svarka-iz-mikrovolnovki.html

Do-it-yourself spot welding/spotter from the microwave

Spot welding is quite in demand in industry. It allows you to quickly and strongly heat a local area of metal. With its help, you can weld individual metal rods in a mesh or two sheets of metal. It will also be useful for unscrewing rusted nuts and bolts; you just need to heat them with this device.

Body repair using spot welding.

Spot welding of two metal plates.

Heating a rusted nut by spot welding.

The operating principle of spot welding is quite simple. The parts to be welded are placed between two electrodes, which exert a compressive force and a high current flows through them, from 500A and above. As a result, the metal is heated to a temperature where it becomes plastic and thus a permanent connection is formed after the workpieces being welded have cooled.

Schematic illustration of the operating principle of spot welding.

The industry uses quite serious spot welding machines that have water-cooled working electrodes and pneumatic clamps. Such devices allow you to weld a large number of points in a fairly short time. But for home use, a simpler device is sufficient.

Spot welding and safety.

This type of welding is quite safe despite the fact that high currents are used to heat the metal. But in addition to the high current strength, a voltage of only 1-3 volts is created on the electrodes. Let us recall Ohm's law for a section of a circuit.

Ohm's law for a section of a circuit.

Substituting a voltage of 2 V and a resistance of 1000 ohms (human resistance) into the formula, we obtain the current strength that will pass through a person - 0.002A. A current of up to 0.1A and a voltage of up to 42V are considered safe.

DIY spot welding assembly from a microwave oven.

In order to make a spot welding machine, we need a transformer. Let's take it from an old, non-working microwave oven. The main thing is that it has a working transformer. Not even necessarily the entire transformer, but only half of it. We only need its working primary winding. The secondary winding is not needed and will have to be removed from the transformer.

Important! Do not under any circumstances connect the transformer to the network in this form! This transformer is a step-up transformer and creates a very high voltage on the secondary winding, about 2000 volts.

Transformer from a microwave oven.

It is very easy to distinguish the secondary winding of a transformer from the primary. The primary winding is wound from wire of a larger cross-section than the secondary and there are fewer turns of wire on the primary winding.

We remove the secondary winding of the transformer. This can be done in different ways. It can be cut with a grinder or a hacksaw. Since copper wire is quite soft, it can be cut with a chisel or chisel. When removing the secondary winding, it is very important not to snag the primary winding. If you damage it, the transformer will have to be thrown away or scrapped.

Removing the secondary winding of a transformer using a grinder.

Removing the secondary winding of a transformer using a hacksaw.

Removing the secondary winding of the transformer using a chisel.

After the protruding parts of the secondary winding have been removed, it is necessary to knock out the remaining windings from the middle of the transformer.

Knocking out the secondary winding from the transformer.

If the winding does not come out, then drill it out using an electric drill, and then remove the remains.

After removing the windings, you need to remove the shunts. They are a set of metal plates wrapped in paper. In the photo below they are circled in red.

Shunts in a transformer.

The purpose of the shunts is to short-circuit the primary winding along the magnetic flux and reduce the flux through the secondary winding. In simple terms, shunts reduce the current on the secondary winding, and therefore reduce the power of our welding machine. Therefore, they must be removed.

Now is the time to tackle the cable. The wire must have copper cores. The wire length is approximately 1.5m. For a welding machine, a wire with a cross section of 50mm2 is best suited, which is approximately 8mm in diameter without insulation. During operation of the welding machine, this wire will heat up from the current passing through it. And the smaller the cross-section of the wire, the faster it will heat up. Therefore, it is advisable to use a wire with as large a cross-section as possible.

If the wire is difficult to screw onto the transformer, then you can remove the insulation from it, wrap it with cotton tape and put a heat-shrinkable tube on top. Thus, the cable with new insulation will become slightly smaller in diameter. The electrical tape must be cotton. It does not melt when heated, unlike regular electrical tape.

In the same way, you can make a wire of the required diameter from several wires of a smaller cross-section, after first removing the insulation from them and twisting them into one core.

All that remains is to put special crimp terminals on the wire. You can simply compress them by flattening them with a hammer or in a vice.

Wire wrapped with electrical tape.

Wire in heat shrink tube.

Crimp terminal.

Wire for the secondary winding of the welding machine.

Now we wind the wire around the transformer. It is necessary to make two full turns as shown in the photo below.

Transformer with new secondary winding.

You can start testing the transformer.

Heating a bolt with a diameter of 5mm using a welding machine.

The bolt is destroyed by heat in just 4 seconds.

The power part of the spot welding machine is ready. All that remains is to make contact pliers with copper electrodes. They can be of very different designs. You can make them at your discretion from various materials. Below, see options for manufacturing contact pliers for a spot welding machine.

An example of homemade contact pliers of a spot welding machine.

Source: https://delairukami.ru/avto/tochechnaja_svarka/

What is needed to make a spot welding machine

The main element of the welding machine is a power transformer, which has a high transformation ratio. The microwave transformer, which is used to power the magnetron, meets precisely these conditions. Its power can be 700-800 W, and even more than 1 kW.

You should know that low-power transformers from microwaves are suitable for making spot welding for working with metal, the thickness of which will be no more than 1 mm. If you need to make your spot welder more powerful, it is recommended to connect two transformers from the microwave together.

Also, in addition to the transformer, to make spot welding from a microwave you will also need some materials.

First of all, this is:

A profile pipe or other rolled metal for making a handle with a base (wooden blocks can also be used);
A spring through which the handle will be thrown upward;
A canopy to make the handle of the welding machine movable;
Copper busbar, for the manufacture of electrode holders;
Copper rods will be used as electrodes for spot welding from the microwave;
A piece of copper cable insulated with a diameter of at least 1 cm. If the cable does not fit into the transformer, then the insulation will have to be removed, after which it is necessary to wrap the cable with several layers of ordinary electrical tape.

After all of the above materials have been found, you can safely begin making a welding machine for spot welding with your own hands.

Remaking a microwave transformer

First of all, you need to remake the microwave transformer so that the output of the secondary winding would have a voltage of approximately 2 V. For these purposes, the factory secondary winding is completely removed from the microwave transformer and a new one is wound with a thick copper cable.

In total, you will need to make 2-3 turns of the secondary winding on the power transformer being converted. You can remove the old secondary winding from the transformer using a hammer and chisel, but you must act extremely carefully so as not to damage the primary winding. It is needed safe and sound for the normal operation of the spot welding machine.

When the transformer has been rebuilt, you can begin making other parts of the welding machine. To make controls, you can use two pieces of profile pipe, 60 cm long, which are connected by a canopy. You can go the other way and make a base with two supports, between which the spot welding control lever will be located.

In general, the controls can be made from anything, even from wooden blocks, if spot welding from a microwave is used for some small work. Clamps for electrodes deserve special attention, which would be best made from a copper bus bar, then drilling holes in them for bolts.

It is the bolts that will subsequently hold the electrodes for spot welding, for which it is recommended to use a copper rod (the larger its diameter, the better). To ensure that the welding machine is turned on only when the handle is pressed, a switch should be placed between it and the base. It should be connected only through the primary winding of the transformer to avoid heavy loads.

Microwave spot welding will be an excellent tool in the hands of a craftsman. Such a homemade welding machine can be used to make other homemade products and metal crafts, of which there are a lot of ideas on the Internet.

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Source: https://samastroyka.ru/tochechnaya-svarka-iz-mikrovolnovki.html