Welding of the car body

 What type of welding is used for auto body?

 

Today we will talk about what type of welding is used for auto body and  what is the best way to weld the body of our car.
If you, as a real car enthusiast, do not want to trust the repair of your "iron horse" to someone else's hands, especially some small work, and also want to save significantly, then this article is for you.

Welding of the car body Content:

1. Welding the car body with your own hands
2. The specifics of welding the body with an inverter
3. Advantages of semi-automatic body welding
4. Useful tips
5. Protect against corrosion
Recently, there has been a growing interest in bodywork. And many people are interested in welding the car body. Someone wants to weld the right part or patch, someone to pull out a dent, someone to fix the traces of corrosion.

 All this can be done with your own hands in the garage. You just need to arm yourself with the necessary tools, learn the nuances of the upcoming work and practice a little.

How to restore the car body using welding?

Welding the car body with your own hands

Probably the first question that came to your mind - what will you need for work? And

which welding machine to choose?

There are two ways of body welding works:

• using an inverter
• with a semi-automatic.

There is also a spot welding option. It is used in factories in the production of cars. Here you need special equipment and some welding experience.
Important! If you have never worked with welding, then be sure to first practice on some metal work pieces.
In the cases listed above, you do not need any specialized skills and abilities. Just a little practice is enough. You can of course immediately start working with the body, but at your own risk to spoil something.

The specifics of welding the body with an inverter

 

Cooking with a welding inverter is easy. The metal heats up to the desired temperature in a matter of seconds, so the entire workflow will take quite a bit of time.

Advantages and disadvantages

The welding current remains stable even with voltage drops and does not create unnecessary loads. Metal spatter is negligible. A nice bonus is the functions of hot start, anti-sticking of the electrode and afterburner of the arc. As well as the inverter consumes 15-20% less electricity compared to other devices.
The disadvantage can be considered only a small thickness of the connected parts - no more than 3 mm. In general, for domestic conditions and even small workshops-this is an ideal device.
You will need to buy only the necessary electrodes for it - they differ in thickness and composition. So be careful when choosing them, because they directly affect the quality of the future weld. In addition, it is worth worrying about a protective mask, gloves and work wear in advance.

The process itself

To begin with, we set the current strength on the inverter - it depends on the thickness of the part and the electrode. It can be determined by the table that is placed on the body of most devices.
Next, we ignite the arc, bring the electrode to our part and hold it at a small angle at a distance of a couple of mm. After that, we begin to weld the parts, and on the resulting and already cooled seam, we knock down the scale with a hammer or brush.
Important! To obtain a strong weld, it is important to consider the polarity.
Let's explain. When welding, there is a positive and negative charge, the electrodes also have poles. At the forward polarity (minus the electrode to the arc), the melting zone is narrow and deep, at the reverse (plus the electrode to the arc) - wide and shallow.
Reverse polarity is used to correct defects in a small area of thickness, where there is a risk of burning metal, and for welding stainless steel, which, due to its chemical characteristics, is more difficult to process.

Semi-automatic body welding

 

Advantages of semi-automatic body welding

To begin with, we will explain that a semi-automatic machine is a welding machine that cooks with wire. Moreover, it is automatically fed to the welding zone. These devices are designated by the abbreviation MIG/MAG.

Pros and cons

These machines are ideal for welding the car body. After all, its thickness can be 0.8-1 mm, and in order not to burn holes in it, semi-automatic welding machines are used. In general, they have twice the thickness range of the welded metal than inverters, and is up to 5-6 mm. It is also worth noting that the quality of welding, even for coarse iron, will be much higher here.
Note. With the help of a semi-automatic machine, thin and almost imperceptible seams are obtained.
A semi-automatic welding machine will completely replace the device on the electrodes, but on the contrary it will not work.
Also keep in mind that learning to cook with an electrode is a long and difficult process. But learning how to cook with a semi-automatic machine is much faster and easier - at least because it does not require the ability to light and maintain the arc.

Semi-automatic machines can safely be called the main type of welding machines for garage workers and services that perform body repairs.
Wire for semi-automatic welding machine

Welding wire selection

 

 The wire can be either  imported. Welding the car body will be successful with any of them, as long as it is copper-plated and free of dirt and rust.
In some cases, the work can be carried out with the so-called “flux” or “self-protective” wire. It is made according to powder metallurgy technologies and contains a protective flux, and therefore does not require the use of a protective gas. But such a wire is much more expensive than ordinary, and the seams do not look as beautiful as when welding with ordinary wire in a carbon dioxide environment.
Note. The most common welding wire diameter is 0.8 mm.
Welding wire can be purchased in almost any tool shop and even a hardware store, if there is a department of welding equipment. 8 mm wire can be used to cook both thin (0.7-0.8 mm) and fairly thick metal-from 4 mm and more.
Let's say finally about one nuance of welding thin metal (about 0.6 mm). The wire here is also more convenient to use less (with a diameter of 6 mm). You can also use it to weld thicker parts. However, only imported brands have such a diameter.

Useful tips:

•  if a long weld is expected
• then regardless of the selected device

It is necessary to act in several stages:

First:

1. the welded part must be "grabbed" in several places so that it is securely fixed
2.  you should make a few short (1-2 cm) seams, along the connection line
3. after each operation, the metal must cool down;
4. and only as a final step - to make the final connection. 
5. this will reduce temperature deformations to a minimum.

Secondly:

• if the car body is being welded due to corrosion damage
• we always remove the rust before starting work
• and you need to clean it completely to the metal. Otherwise, the repair will not last long.
• Protect the car body from corrosion
• Protect the body from corrosion

After the work is done, it is necessary to protect the weld from corrosion. If it remains "as it is", it will be destroyed very quickly. And if this process occurs almost always on the front part of the part, then the inner part is often "forgotten", especially when it is located in a closed cavity.
Important! We apply anti log not only on the outer, but also on the inner surface of the seam!
It is not uncommon for rust to break through the paint after a year along the seam. Moreover, cosmetics, in the described case, will not be able to get rid of-a full-fledged alteration is necessary. When there is access to the processing from both sides , there are no problems.

However

what should I do if the inner part of the seam is in a closed cavity?

 In this case, we recommend that you partially sacrifice integrity and drill a hole in the cavity that will allow you to treat it with anti corrosion.