How to weld correctly and which are the basic rules

How to choose your welding machine and types of electrodes – features and tips

Ca sa inveti cum sa sudezi, ai nevoie de un aparat de sudura adecvat pentru lucrarile pe care le vei efectua. Pentru ca exista tipuri diferite de aparate de sudura, iti prezentam mai jos cum functioneaza fiecare si ce caracteristici au, astfel incat sa il alegi pe cel potrivit pentru tine.

Welding machine with rectifier or transformer type covered electrodes (MMA)
This is the traditional welding machine, which is used for joining pieces of material with the material that results from melting the electrode. In the area where the electric arc is produced, a large amount of heat is released which melts the electrode.
It can be used for bonding different types of materials and thicknesses. This welding machine is recommended for professionals, as experience is required to use it.

Features – you can use it for welding various types of materials, even outdoors or when the wind is blowing. Keep in mind that for thicker materials, it is necessary to apply several layers of material (electrode).
Gas welder (MIG/MAG)
This welder works with inert MIG or active MAG gas. The welding process involves melting a metal wire (thread) that joins two pieces of material together, while a gas is removed to prevent residue from being deposited on the metal surface. Depending on the type of material, gases are used as follows:

• the inert gas can be used for welding metals and materials such as aluminum, copper, or titanium
• the active gas can be used for welding steel

Features – can be used by the beginners, but it is recommended to be used only in enclosed spaces. This type of machine allows you to get a strong weld, even when using thinner materials, and the resulting weld is smooth and clean, with no residue.
Inert gas welding machine (TIG)
The TIG welder uses a non-consumable tungsten or wolfram electrode to bond pieces of material. The gas is released to protect the welding surface against oxidation.
Features – you can use it on ferrous and non-ferrous materials, even if they are thin. You will achieve a precise, strong, and residue-free weld, but the welding process takes longer. Because it is more difficult to use, it is recommended for experienced people.
Autogenous welding machine
This welding machine uses an oxy-acetylene flame and a metal wire to melt metal but is more commonly used for cutting or drilling metal.
Features – can weld even rusty or degraded materials and can be used by the beginners, outdoors or when the wind is blowing. It produces a lot of heat during the welding process and deformation can occur on the surface of the material.
The welding inverter
If you want a device that consumes little energy and is easy to transport, choose a welding inverter. It can be connected to your household electricity supply and is easy to use.
Welding inverters have high power and low energy consumption and weigh between two and five kilograms.
The three main features of the welding inverter are the following:

• Arc-Force – the molten metal droplets from the electrode are easily transferred to the base material and thus the arc interruption is prevented when the electrode and the welded part are short-circuited due to the droplets;
• Hot-Start – primes the arc with a higher welding current for each new weld;
• Anti-Stick – in case the electrode sticks to the welded part, the current is automatically interrupted (you can then easily remove it without damaging it).

The welding inverter is compact and small in size, unlike the traditional welding machines. Welding inverters can be MMA, MIG/MAG or TIG.
Electrode types
When choosing the right machine, you should also consider the type of welding electrodes used, in the case of MMA machines. Our advice is to take a margin of one third less than the diameter of the type of electrode recommended on the welding machine in question. Here are the types of electrodes and their characteristics.
Rutile electrodes

• can be used for alternating current (AC) and direct current (DC) welding with batteries
• the electric arc produced is stable
• they have a high hydrogen content, and the weld pool is fluid (the material added during the welding process)
• they can be used for vertical, horizontal, and thin material welding
• the welding is good, but has a low resistance

Basic electrodes

• they have a low hydrogen content
• the welding bath is viscous, which means that they allow welding in all positions
• the electric arc has a heavy spring and is unstable
• can only be used for DC welding
• the filler material is produced in large quantities
• can be used for thin materials and the weld is strong

Cellulose electrodes

• can be used often and do not produce much waste material
• have high hydrogen content
• can only be used for high voltage DC welding
• produce an irregular weld

The welding process – steps to follow and required tools

Before starting the welding process, you should equip yourself with all the necessary welding tools:

• welding machine;
• welding mask and protective gloves;
• electrodes;
• cables for making the connections;
• hammer and wire brush;
• extension (optional);
• wrench for tightening the contacts to the machine (optional).

Electrode welding process steps
Here are the steps you need to follow if you want to make a correct and resistant welding in a safe way:
Step 1. Make sure that the appliance and the tools are installed correctly.
Step 2. Attach the clamp to the table you’re working on so that you can be sure you won’t get electrocuted while welding if you touch the table.
Step 3. Clip the electrode into the pliers and plug the welder into the socket. The electrode must be dry and have the paste intact.
Step 4. Hold the welding machine with both hands. Place one hand on the end of the welding machine and use the other hand to support the machine from underneath.
Step 5. Start the welding process by lightly touching the electrode to the area where the two materials you want to solder are joined.
Step 6. Gradually adjust the intensity of the arc until you set the optimal value for welding.
Step 7. Alternately touch and withdraw the electrode (1-2 seconds), while making the weld spots, until you observe that enough filler material has been deposited so that the weld is strong. The weld should be in the form of a straight line comprised of small dots.
Step 8. Make sure the weld is on both sides of the materials you want to weld together.
Step 9. Wait a few minutes for the weld to cool and then tap the area with the slag hammer. This will remove excess slag, leaving the area ready for sanding.
Step 10. Clean the weld with a wire brush.