Flux Core Wire Types Title Image

When you’re curious, and you’ve heard there were different types of flux core wire.

When you want to be careful to get yourself the right type of flux core wire for your welder.

Because you want the best repair you can get.

Because your building or creating a new project from scratch. And you want the satisfaction and pride of a good job well done.

Here’s your ABC rundown on the different types of flux core welding wire.

You’ll Find Two Types Of Flux Core Wires.

Self shielded gasless. And you won’t need a tank of shielding gas to weld with it.

Then there’s gas shielded. Because you’ll need a tank of compressed gas.

For both you can buy wire types that’ll weld on the flat or out of position.

Gas shielded flux core welds fast and clean. But costs more to use.

Flux Cored Wire Is A Type Of …

Welding wire you use in your arc welder.

Flux cored wire is called flux core because the welding wire is made like a metal tube.

And the hollow center is filled with flux.

What is this thing called flux?

Flux Core Wire
Flux Core Wire

The flux is a chemical compound that melts in the heat of your welding arc.

The compounds turn to gas in your arc’s heat. And gives your hot metal the protection it needs from the air around your weld joint.

The flux has compounds that puts in – deposits your filler metal at a high rate.

Flux core wires high deposition rates vary from type to type of wire.

The metal on the outside of your flux core welding wire drips into your weld and helps fill up your joint.

Flux Core Wire Welding Mild Steel
Flux Core Wire Welding Mild Steel

When you’ve finished welding your flux core wire leaves a covering over your weld called slag. The slag also works to protect your hot metal from the air as it cools.

And when your welding slag is cool you chip it off. Leaving your shiny clean weld behind.

All types of flux core wire come on a spool. You install your spool of flux core welding wire in your flux core only welder. Or in your MIG welder that welds with flux core wire.

The First Type Of Flux Core Welding Wire You Can Buy

Gasless flux core wire is the first main type of flux core welding wire.

It’s called gasless because you won’t need a separate cylinder of compressed gas to weld with it.

The gasless name doesn’t mean that there is no gas used to protect your weld.  Welding always needs protection from the air. Otherwise your metals won’t fuse together and you’ll get a bad weld.

Why You’ll Like The Gasless Type Of Flux Core Wire

When you want the ease of just using your flux core welder and some wire.

When it’s difficult to buy or take a tank of shielding gas with you.

Or you don’t have the type of gas cylinder you need for the metal you’re welding.

You’ll also appreciate using gasless flux core wire when you’re new to welding. As this type of flux core wire is easier for a beginner to use.

And if you don’t get your weld settings quite right. No matter, you’ll likely get a weld that’ll hold anyway.

Welding with self shielded flux core wire can be cost effective.


Entry level welders often are flux core only welders so your welder itself is cheaper.

There’s no cost for a tank of gas, a regulator or hose to buy.

Welder Welding Icon

The Second Type Of Flux Core Wire

The second type is called gas shielded flux core wire. You’ll also find it’s named dual shielded or double shielded flux core wire.

It’s called gas shielded because when you use this flux core wire you’ll need a cylinder of compressed gas. The gas you use can be 100% Carbon Dioxide, as well as Argon Oxygen mixes. Depending on the flux core wire you pick.

You’ll need a regulator to adjust the speed your gas is fed out at. A hose your gas can travel along to your welder. And a large enough arc welder.

What does that mean?

You’ll find gas shielded flux core in large spool sizes. And your welder needs to be big enough to hold the spool of flux core wire.

The wire also comes in larger diameter sizes. It’s possible to find 0.035 inch diameter gas shielded flux core wire. But typically you’ll find it in sizes of 0.045 inch diameter and larger.

When you’re welding with large diameter flux core wire. You need a welder that can deliver to you enough electrical output. Enough arc output to melt that wire. And the base metals you’re welding.

And that often means a welder that runs on 230+ volts.

All this means gas shielded flux core is a more expensive type of arc welding.

Got all that equipment?

Then …

Why You’ll Like Gas Shielded Flux Core Wire

You’ll like using gas shielded flux core wire when you’ve a lot of welding to do. And you need to do it fast.

Gas shielded flux core welding has the highest deposition rate of your filler metal into your weld of all the welding wire types.

And that’s the main reason you’ll find it in large spool sizes.

And where you weld thick metal – 1/4 inch, 1/2 inch and above.

And why in commercial welding on large projects. You’ll find gas shielded flux core welding.

You also get fantastic welding results. 


Because of the double protection your weld pool has from the air.  It’s protected by the flux inside the flux core wire. And by the shielding gas you use.

Compress Gas Tank Icon

The Different Types Of Flux In Your Flux Core Wire

Your flux core wire has flux in it that does more than just shield your weld from the air.

Mild steel flux core wire has a type of flux made for welding mild steel.

And you’ll find different flux compounds inside flux core wire for stainless steel.

Plus in the flux you get compounds called scavengers or deoxidizers in your flux core wire. They work to help remove impurities from your pool of hot metal.

Why is that useful?

They lift those impurities that would otherwise cause a poor weld. Up to the top of the weld pool where they’re trapped in the welding slag.

And when your welding slag cools you can chip if off. Leaving your great looking weld behind.

Types Of Flux Core Wire For Welding Out Of Position

Some flux core wires have chemicals that help shape your weld pool. Welding out of position means you need a thicker weld pool.

A weld pool that doesn’t simply drip your metal out onto the floor.

Instead that type of flux core wire melts your metal. And your flux core filler wire. Yet keep it as much as possible where you want it.  In your weld.

Pick The Type Of Flux Core Wires For Your Metal

You pick your flux core welding wire to match the metal you’re welding.

Mild Steel Flux Core Wire Type E71T-GS

The flux core wire for mild steel has mild steel. Or low carbon mild steel on the outside of the flux core.

You’ll find it has the letters and numbers E71TGS as part of its name or on the spool. This means it’s made for mild steel and has a strength of up to 70k psi (pounds per square inch). It’s an all positions wire flux core wire made for single pass welding.

Look for the codes E71T-11 when you want a mild steel all positions wire that you can use for multiple passes.

Want to look at the best examples of gas less mild steel flux core wires? Take a look at this document here.

Stainless Steel Flux Core Wire Comes In Different Types.

And you pick your flux core wire to match the type of stainless steel you’re welding.

When you want to weld stainless steel without using gas.

You’ll find some excellent ones here.

And when you want to use gas shielded stainless steel flux core.

Pick the stainless steel flux core wire to match the stainless steel you plan on welding.

You can see some great ones here.

Look Closer – Different Welding Positions Have Their Own Types

Types of flux core wire for the different ways you can weld.

What does that mean?

When you can take the part you plan to repair into your workshop and put it on your welding bench. Then you buy the type of flux core wire that’s for welding on the flat and horizontal.

But when your part is a tractor part. Or you’re welding a gate or fence. Something you can’t take to your workshop or move from where it is. Then you could be welding your metal from top to bottom while you stand or kneel by it.

And what about welding over your head. Or while you’re flat on your back?

Then you’ll want a flux core wire that will work for you no matter the position your weld is in.

This called out of position welding … flux core welding out of the usual flat position.

You can buy both gas less or dual shielded flux core welding wire for out of position welding.  It’s called all position flux core wire.

The Kind Of Flux Core Wire For Single Or Multi Pass

Look closer and you’ll find your flux core wire is made for single pass or multi pass.

What’s that?

When you buy flux core wire for single pass welding. This means that your metal is thin enough. And your flux core welder strong enough to allow you to weld your metal by passing along the joint once.

That’s a single welding pass.

But when you’re welding thicker metal than your welder is up to welding in one go. You bevel the joint. And make as many passes as you need to fill your thicker metal joint with filler metal.

That’s multi pass welding.

Flux core wire for multiple passes are made to bring all the impurities in the weld to the surface at each weld pass.  And for the welding slag at the top of your weld to easily chip off.

Your impurities are in the slag. And the last thing you’ll want is slag buried in the weld you want strong and to look good.

Double shielded flux core wire is excellent for the finish you get after welding. It’s known for the welding slag coming cleanly off.

But don’t worry with the right settings gasless flux core wire also has slag that comes off easily.

Both types of flux core wire can leave a fine weld behind for the next weld pass if you need it.

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