Can You Weld Stainless Steel With Flux Core?

Yes, you can weld stainless steel with the flux core method. Both self-shielded and gas-shielded wires are valid options.

Using flux core welders on stainless steel can produce decent results if you choose the right wire and master the dragging technique.

How Can You Weld Stainless Steel With Flux Core?

Flux-cored arc welding (FCAW) relies on feeding consumable wires with the filler material, just like MIG. The main difference is the shielding mode.

The most common FCAW wire type is the shelf-shielded one. This wire is more than just a filler since it has a deoxidizer core that melts to release a shielding cloud. The cloud is what will protect the molten metal from reacting with the air.

It’s also possible to use double-shielded wires that protect the weld with both the core cloud and external gas.

Both flux core welding methods work just fine on stainless steel as long as the external layer on the wire you’re using is compatible with the piece’s SS grade.

The exact process and required equipment will differ based on the piece you’re working with, but here’s a general guide:

  1. Clean up your stainless steel surface (optional for a sleeker finish).
  2. Place the flux-cored wire in the nozzle.
  3. Check what gas composition you need (for gas-shielded wires only).
  4. Adjust the welder’s polarity to meet the wire’s recommendations.
  5. Strike and pull while welding.
  6. Clean up the slag with a chipping hammer or a steel brush.

Advantages of Welding Stainless Steel With Flux Core

There are a few things to love about FCAW for stainless steel.

Here’s where I think the method shines the most:

Good for Outdoor Welding Jobs

You can choose a flux core if you need to work outdoors often. The setup will be highly portable since you won’t have to carry a gas cylinder.

This also means that the FCAW method can work despite the wind that could blow away shielding gas. That’s why it can be a good fit for farm welders who need to weld stainless steel outside.

If you decide to work indoors, make sure you have adequate ventilation. The fumes from stainless steel flux-cored wires can be toxic.

Cuts Down the Costs

Using the FCAW method can help you save money if you only tackle welding jobs occasionally. That’s because you won’t need to invest in gas equipment, unlike with MIG or GMAW.

Just keep in mind that this applies only to self-shielded wires, not gas-shielded ones.

Suitable for Beginners

Welding stainless steel with a flux core can be easier than TIG. The high deposition rate also makes it good for thicker stainless steel pieces.

The learning curve shouldn’t be too hard to grasp after some practice. The key is finding the right settings.

I’d recommend getting scrap pieces of stainless steel and testing different settings before getting to the main project.

Disadvantages of Welding Stainless Steel With Flux Core

FCAW on stainless steel has its appeal, but there are still drawbacks to consider.

Requires Slag Removal

Flux cores usually leave a lot of spattering and bulky slag behind. That’s why it’s crucial to tackle the piece with a chipping hammer when you’re done welding. Brush bristles will do the trick for smaller splatters.

The catch is that you don’t want to overdo the clean-ups. Stainless steel shows scratch easily.

Keep in mind that you’ll be producing even more slag if you do a lot of passes. Thicker wires can leave more slag, too.

You could opt for TIG or MIG  if you don’t want to deal with slag on your stainless steel.

Good Wires Are Hard to Come By

You need to match the wire’s composition to the grade of stainless steel that you’re working with. You also have to consider the wire thickness.

One downside is that you won’t always be able to find suitable stainless steel wires. The available options are usually more expensive than regular wires, too.

Some people might use mild steel flux-cored wires. It might work as a temporary fix, but I wouldn’t recommend it as a go-to option. Stainless steel welds with non-compatible cores can rust quickly. Any splatter around the welded area will also be prone to rust.

Remember that the main appeal behind stainless steel is its shiny appearance and corrosion resistance. Using the wrong flux wire can compromise all that.

Equipment Required to Weld Stainless Steel With Flux Core

Here’s the basic equipment you’ll need to weld stainless steel with the flux core method:

  • FCAW welder
  • A Spool of flux-cored wire (to match your SS grade)
  • Gas shielder (for double-shielded wires only)
  • PPE (leather apron, welding goggles, helmet, boots, and gloves)
  • Chipping hammer or a steel brush

The common flux-cored SS wire grades are 308 and 309. You can pick up a spool of 316 if you’re working on surfaces that come in contact with food.

You might have to opt for gas-shielded wires if you need to work in vertical positions, though.

3 Stainless Steel Welding Tips

Let’s move on to three simple tips to keep in mind when you’re using flux core welds on stainless steel.

Always Drag With FCAW

Welding methods that produce slag require dragging. This means pulling the wire instead of pushing it. You can start with a drag angle of 10 degrees and see how it goes for your welds.

Check Your Settings

You’ll need to play around with the FCAW settings and find something that matches your skill level. This ensures the best results for your stainless steel welds.

You also need to check the welding parameters recommended by the manufacturer, including:

  • Wire speed (high speeds can be hard to control, and low speeds increase splatter)
  • Polarity
  • Amperage

Prioritize Safety

Some welders could get distracted by the splattering caused by the flux core.

Don’t worry too much about the slag and splattering since you’ll clean them up later. Just make sure you’re prioritizing your safety by watching where your beads are going.

Just like any other welding technique, you still need to stick to the recommended protective gear with FCAW.

Conclusion

Self-shielding FCAW is a portable option for welding stainless steel. It’s great for outdoor jobs since it eliminates the need for gas cylinders. The main downside is that you have to pick compatible wires if you want to avoid quick rusting.

Other welding options, like TIG, might be a better fit if you weld stainless steel indoors only.