Can Welding Wire Go Bad?

By Mgschuler - Own work, CC BY 3.0,

Welding wire, in general, goes bad after a period of time, but depending on the type of welding wire, there are various things to consider in order to prevent it and what to do with it if it does go bad.

Various welding applications require different welding wire. However, like all things metal, welding wire can go bad if it is not taken care of properly. The first thing to do is to know the different welding processes because each welding process uses certain welding wires and may require varying levels of care. 

Keep reading to find out the various welding processes and types of wires, what they are used for, and how to handle those wires when they go bad.

Types of Welding Processes

There are four main types of welding processes, which are listed below.

Metal Inert Gas welding, or MIG, also known as Gas Metal Arc Welding (GMAW)

  • Most common industrial welding process
  • Suitable for fusing mild steel, stainless-steel, as well as aluminum
  • Combines two pieces of metal together with a wire connected to an electrode current
  • Uses a shielded gas along the wire electrode, which heats up the two joining metals 
  • Requires a constant voltage and direct current power source

Flux-Cored Arc Welding (FCAW)

  • Used with or without shielding gas
  • Similar to MIG or GMAW, but it uses a tubular wire filled with flux (solid shielding material used in the welding process) instead 
  • Extremely inexpensive
  • Easy to learn
  • Limitations
    • Not always aesthetically pleasing, unlike other welding methods
    • High levels of noxious fumes
    • Less portable equipment

Arc Welding, or Shielded Metal Arc Welding (SMAW)

  • Most basic of all welding types
  • It uses a welding stick, or metal rod, rather than a wire
    • Uses electric current to form an electric arc between the stick and the joining metals
  • The inert gases, which coat the stick, vaporizes during the welding process and protects the metal
    • Downside is that it produces a lot of slag and requires a fair level of cleanup
  • Often used in the construction of steel structures and in industrial fabrication, as well as for manufacturing, construction and repair work

Tungsten Inert Gas (TIG), or Gas Tungsten Arc Welding (GTAW)

  • Uses a non-consumable tungsten electrode, which heats the base metal into a molten puddle
    • Like SMAW, it uses a filler rod as opposed to a wire
  • It uses inert gas to protect the weld
  • TIG requires a lot of expertise
  • It is mainly used to carry out high-quality, finished work, without the use of sanding or grinding

Types of Wires and Whether They Go Bad

The two main wires include:

1) GMAW wire

Yes, GMAW wires can go bad if they do not have the right protection and maintenance.

Generally, GMAW wires require a shielding gas, which is delivered from a pressurized gas tank, to protect the weld from atmospheric contaminants.

Within this category, the two subcategories are solid GMAW wire and composite metal-cored GMAW wire.

In order to decide which wire is required for a GMAW project, the following factors must be considered:

  • What is the base metal? Compare the base metal to the electrode and match it as closely possible.
  • What is the deposited metal made of? The metal that you want to weld to the base metal may require a certain type of GMAW wire.
  • What deoxidizing agents do you need? They are added to the wires to protect the wires from damage and porosity.

If not, the wires and the welds will be compromised.

Solid GMAW Wires

By Mysid, TTLightningRod. - This vector image includes elements that have been taken or adapted from this:  MIG cut-away.jpg.Vectorized by Mysid on a JPEG by TTLightningRod., CC BY-SA 3.0,
By Mysid, TTLightningRod. – This vector image includes elements that have been taken or adapted from this: MIG cut-away.jpg.Vectorized by Mysid on a JPEG by TTLightningRod., CC BY-SA 3.0,

Both solid and composite GMAW wires have similar performance characteristics and increase efficiency of the weld. They require little to no cleanup. However, they handle varying levels of damage.

Solid GMAW wires are highly deoxidized. They can only handle light to medium exposure to atmospheric elements before it goes bad. On the other hand, composite GMAW wires fare better due to their metallic components. The metal-cored electrode is able to deoxidize the weld scale more effectively.

The level of deoxidizers needed is determined by the number on the end. In the case of ER70S-6, the number is 6. It has higher levels of silicone and manganese than an ER70S-3. The lower the number, the lower amount of deoxidizing agents needed. Again, the level of deoxidizers needed depends on the type of welding project.

Composite GMAW Wires

Composite GMAW wires have a tubular metal core. Like solid GMAW wire, it procures a slagless weld. Therefore, it requires little to no cleanup.

If there are any contaminants on the base metal, composite GMAW wires are able to deoxidize the scale due to their metal-cored components.

The only cleanup required after the weld is complete is removing silicone deposits from the electrode. There is very little spatter and, therefore, very little to clean up.

2) FCAW wire

By Mgschuler - Own work, CC BY 3.0,
By Mgschuler – Own work, CC BY 3.0,

FCAW wire is a hollow wire that is filled with flux.

Flux is a purifying agent, made up of a combination of carbonate and silicate materials. Ultimately, it shields the welds from damage by pushing back any atmospheric gases back and away from the metal.

This composition, paired with a shielding gas, allows for an added layer of protection against atmospheric elements.

Another subcategory of FCAW wire is self-shielded, which is exactly as the name implies. It does not require an external shielding gas in order for it to be protected from atmospheric forces that could threaten the integrity of the wire and the weld.

However, since the wire is not solid, this still allows contaminants, such as moisture, to penetrate the wire.

So yes, FCAW wires go bad if it is exposed to moisture for an extended period of time.


  • Optimal for thicker metal
  • Tolerates more than GMAW wire if base metal is dirty
  • Ideal in windy weather conditions
  • It can work more consistently and reliably for a longer period of time than GMAW wires
  •  Results in usually very strong welds


  • The flux-cored wire puddles, runs out too flat and quickly when used for thinner metals
  • Flux can burn, leaving discoloration on the weld
  • Wire is hollow
    • Builds up moisture on the open end, which can ultimately lead to rust
  • It requires a lot of cleanup at the end, since it produces a lot of slag

How does it go bad

There are many ways that wires could go bad, but the main reason is from atmospheric contaminants. Over time, the wires are constantly in contact with oxygen. They react to it, causing the wires to rust.

This, in turn, affects the wires functionality. A rusted wire will not have the same effectiveness when joining metals compared to a normal wire.

Next to oxidation, wires are also affected by moisture. If the temperature allows for moisture, then the wire will rust. As mentioned above, FCAW wires are particularly susceptible to moisture because the core is hollow, which allows water to seep in more easily.

After rust and moisture, in the actual process of welding, there is the possibility of weld slag, weld scale, and weld spatter.

How to prevent it

The most common ways to prevent it are to learn proper storing techniques, as well as using deoxidizing agents and shielding gases.


Deoxidizing agents vary. Silicone, manganese, and aluminum, and occasionally, titanium and zirconium, are the most common.

Essentially, deoxidizers defuse the oxygen as the metal cools. It reduces the chances of rust without compromising welding performance or arc quality.

Although manganese provides deoxidizing capabilities and increases the strength of the overall weld, it causes some health concerns due to the fumes it produces.

Silicone works well to provide a smooth and flat weld product and aluminum works well as an added deoxidizer since too much aluminum compromises the stability of the weld. The more aluminum in the filler metal, the more brittle the weld is.

Shielding Gases

Shielding gases minimize exposure to the atmosphere. However, depending on the welding process needed, a shielding gas may or not may be required. Once the welding process has been determined and a shielding gas is required, the next step is choosing the right gas.

Shielding gases are typically used in MIG welding, or GMAW. The most common shielding gases are argon, helium, carbon dioxide and oxygen.

Carbon Dioxide

Out of these, carbon dioxide is the most common of the shielding gases. It is inexpensive and is the only one that can be used in its pure form without the use of inert gases. While these are intriguing factors to consider, there are some concerns on the actual effectiveness of carbon dioxide, since it produces a less stable arc and more spatter when mixed with other gases.


Helium is similar to carbon dioxide in terms of its functionality. However, it is more expensive and it requires a lot more of it to achieve the same result.


Oxygen serves a specific function for stainless steel, mild carbon, and low alloy welds. It improves arc stability and penetration. Even though it can perform these functions, since it is oxygen, it causes oxidation of the weld metal, which allows the welding wire to rust.


Argon, on the other hand, is best used in a mixture to increase arc stability.  If the weld uses aluminum, magnesium, or titanium, it is preferable to use one hundred percent pure argon, since these metals are non-ferrous. This means that these metals do not contain iron, are not magnetic, and are more resistant to corrosion.

Argon conducts a low amount of heat, which is why it is mainly used with the metals mentioned above. Even though these metals are strong, they are light-weight and do not require a high amount of heat to manipulate them.

Other Considerations

Another thing to consider when figuring out whether wires can go bad is the consistency of the wire. No two wires or electrodes are the same. When looking for the quality of the wire, look for consistent chemistry, wire diameter, and arc performance. Any inconsistencies affect the functionality, the operating cost, and the overall quality of the weld.

Additionally, proper handling technique plays a major role in the maintenance of welding wire. Moisture and cool weather causes a lot of damage. Rust and other contaminants damage the quality and integrity of the filler metal. Because of this, store welding wire in a temperature-controlled storage cabinet when it is not being used.

Follow these simple procedures and welding wire will last for years without going bad. If there is any bad wire, read below for what to do. 

What to do with bad wire

Usually, when something goes bad, the first thought is to throw it away. However, that does not always have to be the case.

Typically, there is only partial damage to the wire. If so, all one needs to do is remove the damaged wire and the rest of the spool is good as new.

Toss the rusty wire or save it for another project. There are endless possibilities of how the rusty wire could come in handy.

In the end, welding wire can go bad, but there are many ways to prevent it. By following those precautions, welding wire could last over ten years and even if it does go bad, there are other options besides throwing it away.

3 responses to “Can Welding Wire Go Bad?”

  1. Great information, however, it’s very difficult to read your page with the light gray text on a white background. I had to highlight the text in order to read it without eyestrain.

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