More costly filler material/wire as compared to GMAW.Porosity – the gases (specifically those from the flux-core) don’t escape the welded area before the metal hardens, leaving holes in the welded metal.Irregular wire feed – typically a mechanical problem.Melted contact tip – when the contact tip actually contacts the base metal, fusing the two and melting the hole on the end.But there are a few concerns that come up with FCAW that are worth taking special note of: Of course, all of the usual issues that occur in welding can occur in FCAW such as incomplete fusion between base metals, slag inclusion ( non-metallic inclusions), and cracks in the welds. Less equipment required, easier to move around (no gas bottle).Metallurgical benefits from the flux such as the weld metal being protected initially from external factors until the slag is chipped away.As compared to SMAW and GTAW, there is less skill required for operators.Some 'high-speed' (e.g., automotive) applications.A high-deposition rate process (speed at which the filler metal is applied) in the 1G/1F/2F.No shielding gas needed with some wires making it suitable for outdoor welding and/or windy conditions.FCAW may be an 'all-position' process with the right filler metals (the consumable electrode).

Reverse polarity (Electrode Positive) is used for FCAW Gas-Shielded wire, Straight polarity (Electrode Negative) is used for self shielded FCAW.

Shielding gas composition (if required).

However, like GMAW, it cannot be used in a windy environment as the loss of the shielding gas from air flow will produce porosity in the weld. In practice it also allows a higher production rate, since the operator does not need to stop periodically to fetch a new electrode, as is the case in SMAW. The main advantages of this process is that in a closed shop environment, it generally produces welds of better and more consistent mechanical properties, with fewer weld defects than either the SMAW or GMAW processes. The slag created by the flux is also easy to remove. This particular style of FCAW is preferable for welding thicker and out-of-position metals. The most common blend used is 75% Argon 25% Carbon Dioxide. The most often used shielding gases are either straight carbon dioxide or argon carbon dioxide blends. In fact, since it uses both a flux-cored electrode and an external shielding gas, one might say that it is a combination of gas metal ( GMAW) and flux-cored arc welding (FCAW). This type of FCAW was developed primarily for welding structural steels. This is known informally as 'dual shield' welding.

Another type of FCAW uses a shielding gas that must be supplied by an external source.

Flux core welding