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What is Welding Flux

There is some mystery involved with the term“welding flux.” Hopefully, this article will give you a better understanding of what flux is, what its functions are, and how to store flux and consumable stick and wire electrodes.

Fusion VS. Non Fusion: When soldering copper or brass, a non-fusion process, the area has to be cleaned first. The most common chemical used for this is muriatic acid. After the joint or area to be soldered is cleaned the metal is evenly heated and the “flux” is applied; it’s usually brushed on. When the metal is heated solder is added manually and the metals become joined. (The same process holds true with “brazing.” In brazing steel, the area is cleaned, the metal is heated and the brazing rod is heated and dipped into the can of “flux” and used that way.)

However, “welding” metals, fusing them together, requires more than just heating the metals to be joined. When welding, the base metals along with the welding rod or wire electrode need to be taken to high temperatures for fusion. This causes chemical reactions that do not exist at low or moderate temperatures.

Flux, Rod, Gases And Heat: The electrode, a coated rod or wire, the base metal (s) and the heating action itself react chemically with the oxygen and nitrogen in the air. During the process the metal must be protected from these reactions so the strength and integrity of the welded joint can be assured. Therefore, the stick or wire electrode and the flux it provides, cover the arc and the molten pool with a protective shield of gas and vapor. “Shielding the arc” is the term most often used.

With welding rods and wire electrodes the “flux” is applied in the factory. The flux has several functions:

  • It helps to clean the metals surfaces.
  • It helps to join the filler metals to the base metals.
  • It provides a protective barrier against igniting.
  • It helps with heat transfer from heat source to metal surface and it helps in the removal of surface metal wastes.
  • It also helps the deposits of metal from the electrode.

With any low-hydrogen or wire electrodes, it is imperative to use proper storage procedures. Welding rods and wire electrodes need to stay in their sealed container. Once opened and the electrode is exposed to the air (even for a few hours in humid conditions) they should be reconditioned and then stored in a rod oven until used. (When in doubt always consult the manufacturer or suppliers recommendations.) has a wide range of reconditioning and holding ovens, in all sizes, models, and shapes. We also carry unheated storage containers and replacement parts for ovens. We feature a 30-day money-back and guarantee FREE shipping to your business.

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