.030 vs .035 Flux Core Wire: What’s the Difference?

Flux core welding is a semi-automatic process similar to MIG welding. Both processes use similar equipment, continuous wire feed electrode, and they have a relatively high production rate. The main difference between the two processes is the type of electrode used and how the weld is shielded from contaminants.

MIG welding uses a solid wire and a bottle of gas for its shielding, but the method has its share of drawbacks when welding in drafty conditions. On the other hand, flux-cored welding uses a hollow wire filled with flux, hence the name “flux core”.

The flux shields the weld from atmospheric contaminants and oxidation. Using a flux core wire allows the operator to weld outdoors or in windy conditions since no shielding gas is involved.

Flux-cored wires are available in a range of sizes to suit different applications. One of the most frequently asked questions among welders, especially beginners is, “what size flux core wire can I use with different materials?” Flux core wires are available in a variety of sizes (i.e., the size of diameter), but the common flux core wire sizes are 0.030 and 0.035 inch wires.

This article will settle the debate of .035 vs. .030 flux core wire to determine what wire to use and for what project.

Here is a quick comparison

.030 flux core wire	.035 flux core wire
Ideal for thinner metals	Ideal for thicker metals
Welds materials up to 1/4 inches	Welds materials up to 1/2 inches
Low amperage	High amperage
Affordable	Costly

Similarities between .030 and .035 flux core wire

Both wire sizes are flux-cored, meaning they do not require shielding gas, and they are ideal for outdoor welding in windy conditions. The wires produce a shielding gas as the flux coating melts to protect the welded area.

This also means that they are more portable since you don’t need to carry an external shielding gas bottle. Furthermore, you can use both for out-of-position welding processes since shielding gas is not a requirement. Also, they are ideal for all kinds of applications from general fabrication and manufacturing.

Additionally, both wires are more forgiving when working with dirty or rusted materials. As such, you can weld any metal, whether clean or dirty, with both wires. However, you may still need to clean the metals before welding to minimize the risk of porosity.

What is the difference between .030 and .035 welding wire?

Now, as you may have understood, the only difference between the welding wires is mostly about the difference in diameter. From the two numbers, it is no brainer that the .035 is thicker than the .030(a difference of .005 inches).

So, what does this difference in diameter mean?

The wire diameter is simply about the wire’s capability to let you work with a range of material thicknesses.

If you are working with thin materials up to 1/4 inch, the .030-inch wire is an ideal option to start with. It is typically more affordable than .035 welding wire, and it has a high deposition rate with low splattering.

The market is filled with different .030 flux core wire models that you can use to work on various materials including, galvanized metal, auto body parts, and more. Provided that you choose the correct size metals, then you don’t have to spend a lot of time cleaning up the welded part.

On the other hand, if you are looking for an all-around welding wire to weld thicker sheet of metals, then you can use the .035-inch wire. This wire diameter also allows you to use a higher heat level, although this will be dependent on the welding machine output range and the type of flux core welder you’re using.

And because thicker electrodes burn hotter than thin ones, the .035 flux core wire offers deeper weld penetration. However, it will require a higher amperage machine than a .030 wire. As such, when using a .035 electrode, you may want to invest in a more powerful welder.

.030 vs .035 flux core wire-Which is the best choice?

When comparing the .030 wire to .035, it is important to note that the ideal choice is dependent upon the welding task at hand. When done correctly, both wire sizes can produce stable welds with the desired appearance.

The difference in thickness is very small, and it is sometimes challenging to determine the ideal choice in different situations. For thinner materials below 1/4 inch in thickness, the .030 welding wire works best.

For thicker materials (1/4 inches and above), .035 can work outstandingly well. It welds through thick and heavy metals pretty fast, but you should avoid thin materials to prevent burning through.

So do we have an outright winner? The correct answer to that is a straight “No”. The question of which one is best will depend on your specific welding needs.

Instead of trying to establish which is superior to the other, you should focus on the materials you have before choosing the most suitable welding wire.

Ideally, both welding wires are relatively easy to use and beginner-friendly, but the .035 wire is more costly. Also, as a beginner, you’ll find the .030 flux core wire more convenient to use. Regardless, it is critical to ensure that you adhere to safety precautions with any welding application.

As the first step, ensure you determine the type of material you are working with and the nature of your welding machine to determine which welding wire to choose.