How to weld Flux Core

How To Weld Flux Core?

Welding requires specific skills, knowledge, experience, talent, and certain talents. There are many types of welding, but Flux Cored Arc Welding is the most convenient. Below is everything you need about flux-cored arc welding.

How Flux-Cored Arc Welding Works?

In FCAW, a continuous wire-fed electrode is used. A constant voltage welding power supply through fair connections and the same equipment as metal active gas welding(MAGW). Flux-cored arc welding can be done with or without shielding gas, irrespective of the supplied gas. It is far more efficient and economically profitable than MAG welding.

In FCAW, you use the heat from an electric arc to fuse base metal in the joint area and make a tight joint. It uses a tubular or hollow electrode filled with a flux compound. It creates gas and protects the pool.

DUE TO ITS PENETRATIVE QUALITIES AND HIGH DEPOSITION RATES, the FCAW process is widely used for outdoor welding and welding on contaminated materials. Flux-cored arc welding doesn’t require an external shielding gas to protect the weld against atmospheric elements.

FCAW is used for thick materials. You can use it later to give it a polished look.

Flux-Cored Arc Welding Types

There are two types of flux-cored depending upon shielding gas, arc welding. The shielding method is the main determinant of which type it is.

FCAW by external gas

Dual shield welding is a method that uses carbon dioxide and flux to add shielding. Carbon dioxide, argon, and argon mixtures (75%) and carbon dioxide (25%) are the most popular shielding gasses.

In this process, carbon dioxide is shielded to protect the weld from metal oxidation. It can be supplied externally via a high-pressure gas cylinder. The slag that forms from flux melting protects the metal.

It is used when thicker metals and materials need to be welded together. Continuously fed cylindrical electrodes allow for high deposition rates and increased production (compared with stick or solid electrodes).

The only problem with this process is that strong winds could disrupt the carbon dioxide gas shielding and cause problems in welding quality under harsh outdoor conditions.

FCAW uses the flux core to protect your weld area

This method uses the gaseous protection the flux-cored electrode provides to protect and cover the molten metal or material in the weld. In this method, the filler wire core has agents that by internal spark form shielding gasses.

This type of welding can be used extensively in heavy outdoor projects regardless of the weather. This type of welding is ideal for external applications because it doesn’t require external shielding gas and is independent of airy circumstances. Windy conditions won’t interrupt the process, so you don’t have to use an external shielding gas.

Required Equipment for FCA Welds

You will need the following basic equipment to flux-cored arc weld:

  • Power source: The power source, or welding machine, supplies the voltage and amperage that allows the welding arc to continue and start the initial pre-heating process.
  • This type used both water-cooled and air-cooled guns. While air-cooled guns are simpler to operate, water-cooled guns provide greater efficiency.
  • Welding cables – Connector cables are generally made of copper and connect your welding gun to the power source.
  • Wire feeder This wire feeder connects the electrode through the cable and welding gun and has an electric rotor connected with a gearbox containing drive rolls to carry out a smooth operation.
  • Shielding gas equipment for flux-cored welding: Eventually, flux-cored arc welding can be done with or without shielding gas. But while using the gas, it is necessary to use a gas supply line, regulator, control valves, and supply hose for certain applications for a smooth process.

Flux-Cored Arc Welding Electrodes

The difference between flux-cored and MIG welding is made by using electrodes. The former uses filler material or metallic wires, while the former uses hollow electrode wires filled with flux. The flux fills the electrode wires, protecting the weld joints from corrosion or contamination by natural elements.

What Metals Can You Weld With FCAW?

Because of its versatility and popularity, FCAW is one of the most widely used welding processes. Flexible FCAW can be easily used to weld metals such as cast iron, stainless steel, and carbon steel.

Pros And Cons of FCAW


Flux-cored arc welding is used in many industries, including construction, heavy equipment repair, and structural steel erection. FCAW can be used on any material, even if it is contaminated, unlike other welding processes.

It can cause rust and mill-scale dissolution.

Here are some pros and cons of flux-cored arc welding.

  • This welding technique has higher deposition rates per hour than other methods.
  • Corroded, rusted, and contaminated delicate metals are easy to weld with flux core welding.
  • The flux shield makes this welding process ideal for outdoor and indoor welding.
  • Flux-cored arc welding is very easy to learn and comes in handy for beginners.
  • This welding method is independent of high levels of manual dexterity and complications, as in TIG welding.
  • FCAW requires very little extra equipment. It makes the welding process simple.
  • FCAW has better mechanical consistency, stronger weld joints, and fewer weld defects.
  • It is ideal for stainless steel, carbon, and low-alloys steel.


The FCAW process has very high efficiency in reducing deposition and protecting against wind and other atmospheric weathering. But, there are some limitations that you must know:

  • The Flux core arc welding is not automated and is a manual process. There can be some manual or mechanical errors that could cause a loss of precision and decreased efficiency of work.
  • It can be dangerous to work near toxic fumes and smoke. Therefore, we recommend that this type of welding is done in an area with good ventilation.
  • An FCAW (electrode) wire costs more than a regular electrode wire.
  • Removing slag continuously while welding is important to achieve a smooth and finished surface because it can hinder your welding process.
  • FCAW welding is more costly than other types of welding because there is a lot of material loss, and it is less efficient than others.


The difference between a good and bad weld can be determined by factors such as the electrode angles, wire feed speed and voltage, electrode extension, and electrode length. You will encounter common issues when working with a flux core welding process. We will help you to fix them or prevent them from happening while welding with FCAW.

  • Common wire feeding issues like birds nesting and burning back can lead to tangling or even extinguishing the arc during welding. You should ensure a wire feed speed of at least 1.25 inches and a distance between the contact tip and workpiece.
  • A wrong tension on the drive roll can cause the wire to tangle and flatten. The wire feeder can be fitted with U- or V-shaped grooves. It will allow you to adjust the tension.
  • Due to incorrect travel speed, heat input, or angle, slag inclusions can hinder the weld’s penetration. With short intervals, clean the welding work and use appropriate and adjusted heat input and methodology.
  • Porosity can occur when the heated-up flux-cored wire electrode’s gas gets stuck in metal. Avoid excessive voltage because it can damage the core weld and clean any dirt, dust, or oil accumulated on the base, which will interrupt the point of contact.

Difference between SMAW, GMAW, and FCAW.


 In Metal Inert Gas welding (MIG), GMAW or Gas Metal Arc Welding uses a continuous, solid wire electrode and shielding gas that fuses with welding metal to form a tight joint.

Gas metal arc welding is used in commercial processes such as vehicle manufacturing, construction, and aerospace. This type of welding requires external gas so that wind can cause problems. GMAW can be used as a semi-automatic or fully-automatic welder technique.

FCAW is very similar to GMAW. It is independent of external shielding gas. It is based on a continuous wire-feed process. Two distinct processes are involved in flux-cored arc welding. One involves shielding gas.

FCAW relies on self-shielding agents, which are produced and fed through the wire when fluxing agents break down within the welding wire by electrical supply.


Shielded Metal Arc Welding (SMAW), also known as “stick welding,” is a method of welding on all Iron alloys. The electrode coating helps to de-oxidize any weld areas. It creates a shielding agent that protects the weld from atmospheric contamination.

SMAW can be used indoors or outdoors to weld low-alloy and higher-alloy steels, nickel alloys, carbon steels, and cast iron (like FCAW). SMAW creates a layer you can remove later, just like flux-cored arc weld.

Flux-cored, semi-automatic, or manual welding techniques are seldom used indoors. It is used on contaminated materials or outdoors. An electric arc fused the base material with a continuous metal filler electrode. The flux acts as a shielding gas to protect the weld pool against the elements.

Tips to improve FCAW

These tips will ensure your joint is flawless and free from complications.

  • To prevent molten metal from causing a mess, spray an anti-spatter solution on your part.
  • One way to avoid burning back is ensuring you have the right wire feed speed and MIG gun-to workpiece distance at your work.
  • Always use U-groove or V-groove drive roll knurled in your wire feeder to prevent wire tangling.
  • You should ensure enough space in the joint to allow for multiple passes.
  • To avoid unwanted slag inclusions, maintain a steady speed of travel.
  • Before moving on to the next weld pass, use a wire brush or chipping hammer to remove slag.
  • To avoid excessive or poor penetration, ensure that you maintain the appropriate heat input, voltages, and filler wire speed.
  • You can prevent porosity when welding by removing grease, rust coating, oil, dirt, and paint from the base metal.
  • One way To keep the weld clean is to use an advanced filler with additional de-oxidizers that speed up the process.
  • After the above step, maintain a proper stick-out or extension for your electrodes.

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