Tips for welders: how to properly prepare the material before welding?

# Tips for welders: how to properly prepare the material before welding?

Welding is an art that requires not only precision in execution, but also careful preparation of the materials to be joined. Proper preparation not only ensures the quality and strength of the weld, but also the safety of the welder. This article is intended for hobby welders and aims to provide detailed guidance on the essential steps to take before you start welding. We will also discuss the different types of products that can be used to effectively prepare surfaces, including the use of twisted wire brushes.

# The importance of good preparation

The preamble before any weld is to understand why material preparation is crucial. Impurities such as rust, paint, oil, or even dust can negatively affect the quality of the weld by creating weak spots or causing defects such as porosities or slag inclusions. A clean and well-prepared surface allows for better metal melting, which enhances the structural integrity of the weld.

Step 1: Cleaning the surface
Cleaning metal surfaces prior to welding is essential. Start with a coarse cleaning to remove visible debris and thick layers of rust or paint. Use a wire brush or grinder with a flap brush to rough out the surface.

Mechanical brushing: for a finer cleaning, opt for a brush with twisted wires, which is particularly effective at removing rust and small particles. Twisted wire brushes have metal wires twisted together, making them sturdy and able to handle uneven surfaces without getting damaged quickly.

Degreasing: After brushing, use chemical cleaning to remove oils and greases. Use solvents such as acetone or industrial degreaser. Be sure to work in a well-ventilated environment and use personal protective equipment (PPE), such as gloves and safety glasses.

Step 2: Prepare the edges
Preparing the edges of the workpieces to be welded is also crucial, especially for large welding jobs. This step involves forming the edges of the metal parts in such a way that they fit perfectly during assembly.

Chamfering is a technique that involves cutting the edges of metal at a precise angle to facilitate better penetration of the filler metal. This is especially important for high-load welds, where the strength of the weld is paramount. 

Checking for fits: Make sure the parts fit together properly without large gaps. Gaps can be filled with filler metal, but a precise fit minimizes the amount of metal needed and ensures a cleaner, stronger weld.

Step 3: Choice of filler metal
The choice of filler metal is crucial because it must not only be compatible with the base materials, but also meet the specific requirements of the weld in terms of mechanical strength, ductility and corrosion resistance. Here's how to choose the right filler metal:

Material compatibility: Make sure the filler metal has similar properties to the materials to be welded. For example, to weld carbon steel, use a carbon steel rod or wire. For aluminum, opt for an aluminum-specific filler wire.

Diameter of the filler metal: The diameter of the filler metal depends on the thickness of the parts to be welded. A wire that is too thin might not fill the joint properly, while a wire that is too thick could be difficult to melt properly. As a rule of thumb, the diameter of the filler metal should be similar to the thickness of the thinnest material you are welding.

Composition of the filler metal: Check the chemical composition of the filler metal to avoid inclusions of impurities that could weaken the weld. For example, some filler wires are lightly alloyed with other elements to improve certain properties, such as corrosion resistance for exterior welds.

Coating type: For arc welding with coated electrodes, the type of coating of the electrode plays an important role. It helps stabilize the arc and protect the weld pool from oxidation. The electrodes are classified according to their coating and optimal welding position.

Step 4: Welding Equipment Adjustments
Correct equipment settings are essential to achieve a quality weld. Here's how to adjust your welding equipment:

Power Source Selection: Choose a power source that is suitable for the type of welding you are doing (MIG, TIG, MMA, etc.). Each method has its own requirements in terms of current type (AC or DC) and power. 

Adjustment of the current intensity: The intensity of the current must be adjusted according to the thickness of the material and the type and diameter of the filler metal. Too low a current will not melt the metal properly, while too high a current can cause spatter and excessive penetration, damaging the material. 

Welding speed: The speed at which you move your torch or electrode also affects the quality of the weld. Too fast a speed can result in a weak, underfused weld seam, while too slow a speed can lead to overheating and deformation of the material. 

The arc voltage, combined with the intensity of the current, determines the shape and quality of the electric arc. Properly set tension helps control the width and depth of arc penetration, as well as the stability of the arc itself. 

If you're an amateur welder, take some time to practice on scrap metal before you start your main project. This will allow you to familiarize yourself with welding techniques and test the settings of your equipment. Also, perform destructive testing, such as bend or tensile testing on your welds, to assess their strength.
Proper preparation of materials prior to welding is an essential step that should not be overlooked. By following these tips and investing time in preparation, you will significantly increase the quality and safety of your welds. Remember, patience and precision are the keys to a successful weld. Happy welding!