Best Flux Cored Wire for Mild Steel Why These Are the Boom

By Bill Byers / March 8, 2019
Best Flux Cored Wire For Mild Steel

Welding with flux cored wire is one of the most popular welding processes around and for good reason.

I’ve researched for you the best flux cored wire for mild steel. I explain why these are the best and I give you some advice for all you home hobby welders.

Best Flux Cored Wire for Mild Steel Laid Bare

1. INE INETUB BA71TGS Mild Steel Flux Cored Wire (*Paid Text and Image Link)

INETUB Flux Core Wire For Mild Steel

  • Wire Diameter Sizes: 0.030 or 0.035
  • Weight Available: 2 lb. spool or 10 lb. spool
  • Welding Positions: An all position wire that supports single pass welding.
  • Low spatter, easy slag removal
  • A well liked wire with over 250 pieces of Amazon feedback much of which is very good. The small amount of bad feedback were where people found it didn’t suit their particular welder or wire nesting off the spool problems.

Have a think about getting US Forge 400 welding Gloves with this wire. (*Paid Link)

2. Blue Demon E71TGS Mild Steel Flux Cored Wire (*Paid Text and Image Link)

  • Wire Diameter Sizes: 0.030 or 0.035
  • Weight Available: in 1 lb. spool or 2 lb. spool or 10 lb. spool
  • Welding Positions: H, F, V, O – Horizontal, Flat, Vertical, Overhead.
  • Supports single pass welding.
  • A well priced, popular wire with much good Amazon feedback. The small level of poor feed back seen seemed to be around the wire not gelling with their Welder, excess spatter and wire winding issues

Contact tips or Cantesco Nozzle Tip Dip are useful to get with this wire. (*Paid Links)

3. Lincoln Electric Inner shield NR-211-MP Mild Steel Flux Cored Wire (*Paid Text and Image Link)

  • Wire Diameter Sizes: 0.030 or 0.035
  • Weight Available: 1 lb. spool or 10 lb. spool
  • Welding Positions: an all position wire that supports single and multi pass welding
  • Although there may be lower numbers of Amazon feedback, this is great wire and is very well regarded for running well and producing good welds. Seems the users who dislike the INETUB or Blue Demon got on well with the Lincoln Electric Innershield.

4.Hobart E71T-11 Mild Steel/Carbon Steel Flux Cored Wire (*Paid Text and Image Link)

  • Wire Diameter Sizes: 0.030, 0.035
  • Weight Available: 2lb spool or 10 lb. spool
  • Welding Positions: an all position wire. Supports single pass and multi pass welding.
  • Good solid feedback on the wire apart from some small shipping problems, and where the user just didn’t get on with the wire in their welder.

Think about getting with this wire Hobart Nozzle Gel and the Hobart Multi-function Pliers. (*Paid Links)

The one wire that nearly made the grade is the Forney flux cored wire. (*Paid Link) It is worth taking a look at particularly if you have a Forney flux core welder.

Note: These wires are available in larger diameter sizes and spool sizes. I’ve focused here on the diameter sizes and spool sizes likely to be used in the welders bought by the home workshop user.

Lincoln Electric NR-211-MP Wire In Welder

Lincoln Electric NR-211-MP Wire In Welder

Why are these the Best Flux Cored Wires for Mild Steel?

  1. Because they are branded products. Buying unbranded wire leaves you open to pot luck. You may get some good wire, you may not.

Unbranded wire manufacturers tend not to have as stringent quality control, the wire’s chemical make up may not be as consistent all the way through the spool, you may have feeding issues as the diameter of the wire isn’t the same at all parts of the spool.

  1. They have received a good level of feedback and have a good reputation in the market. Just because you weld at home doesn’t mean your projects are not important.
  2. Where you may lack in skill good quality wire is more forgiving.
  3. These are all self shielded flux cored wires which mean you do not need separate shielding gas to weld. It also means they can be used with the entry level flux core only welders.

What is Mild Steel?

Mild Steel is also known as low carbon steel that has no more than 0.05% to 0.025% of carbon. It is widely used for a variety of parts and uses, as it is low cost to make and shape. Where metal rusts, the odds are it is mild steel. Has a dull sheen means it may be galvanized. (Note a high sheen may mean the metal is stainless steel, and you should then choose a flux core welding wire suitable for stainless steel).

Much of the metal you will find about the home and yard is made with low carbon steel and so is very weld-able by the home user with a competent welder.

Welder Welding Mild Steel With Flux Core

Welder Welding Mild Steel With Flux Core

Will Flux Cored Wire for Mild Steel Weld Galvanized Steel?

Yes, flux cored wire will weld galvanized and zinc coated steel. Note that when you weld with mild steel the steel will not retain its galvanization.

The galvanization will burn off and much will be converted into the smoke coming off the weld.

(Keep your head out of the weld smoke when welding with flux core and particularly when welding galvanized steel or zinc coated steel.)

Once welded, to restore the galvanization the weld will need to be painted to protect it or spray galvanized.

Why is Flux Core Wire Generally Higher Priced than Solid Wire?

Yes, you do pay a premium for flux core wire and there is good reason for that.

Actually the flux core wire itself is only a fraction of the overall cost of flux core welding when you compare it to welding with solid wire and shielding gas.

Let me explain …

1. If you were welding with solid wire and gas you have not only the wire cost – which ok is cheaper – you have the cost of a cylinder of gas, transportation and storage of the C25 gas (75% Argon, 25% Carbon Dioxide).

2. You can do things with flux core wire that you can’t do with solid wire.

Vertical up welding, welding over galvanized, or for welding difficult to weld steels. Flux core is a better option and you can get your weld done faster.

3. Welding outdoors? Flux cored welding for mild steel is better for welding outdoors because you have less to carry with you to the weld site (no shielding gas to carry.) You would need some tenting set up to protect your weld area if you were using separate shielding gas – extra cost in terms of materials and convenience.

Flux Core Weld of Mild Steel

Flux Core Weld of Mild Steel

4. Flux core is more tolerant of dirty steel than welding with solid wire.

Even though it is best to start with clean steel, as clean as you can get it, where you can’t get the weld scrupulously clean flux core wire is your savior.

5. Self shielded flux cored wire for mild steel is more easily used by the beginner or home work shop and garage welder as it is a simple set up. (As no separate shielding gas is needed.) And is more forgiving of the skill or rather lack of skill of the person welding.

Set your welder’s voltage and wire feed and armed with your welder filled with flux cored wire for mild steel you are good to go.

6. You’ll get better penetration of thicker mild steel with flux core wire.

7. You can get away with having a flux core only welder. If you are only welding occasionally, small amounts and welding mild steel then a flux core only welder is a cheaper welder to buy.

YouTube Video Comparing Two Weld Wires

This YouTube video is a good primer comparing the wire from Harbor Freight to Lincoln Electric Innershield. I hope you enjoy it as much as I did.

Harbor Freight Flus Core Wire Vs Lincoln Flux Core wire part 2 of 2

Video Credit:

What are the Disadvantages of Flux Cored Wire for Welding Mild Steel?

  1. More plume and smoke is produced particularly if you are welding dirty steel or galvanized steel. Those compounds should not be breathed in. Keep your head out of the plume or wear a respirator if welding in a tight enclosed space.
  2. Flux cored wire can produce more spatter as you weld. (Choose a good quality low spatter wire.)
  3. More slag is produced, as the impurities in the weld are held in the slag. This slag needs to be removed between each weld pass.
  4. Flux core wire is more expensive to buy.

Flux Core Wire Types

A flux cored wire is literally a wire with a hollow center. The welding material – mild steel is around the outside of the core. In the center the flux is held.

Inside Flux Core Wire

The flux consists of compounds that when melted and welded form a protective barrier around your weld pool shielding the pool from the contaminants in the surrounding air.

The flux also contains compounds that help shape the weld pool and increases the deposit rate of the metal – in this case mild steel. Scavengers or Deoxidizers help to remove impurities from the weld site and trap them in the slag that can be later chipped off.

There are two types of flux core wire, one that is gas shielded and the other is self shielded

Gas shielded flux core is mainly used in the commercial space and is available in large spools to reflect that. That is why I have concentrated on the self-shielded gasless flux core wire for mild steel in this article.

Lincoln Electric NR-211-MP

Lincoln Electric NR-211-MP

What does the Specification Code on the Flux Core wire for Mild Steel Mean?

The specification and standards are set by the American Welding Society (AWS).

The E means the wire is an electrode. i.e. a continuously fed wire that acts as the electrode and is consumed into the weld pool. The wire is fed through your welder up through the hose to the MIG gun.

The 7 means the wire tensile strength is up 70,000 pounds per square inch

The 1 means the wire is an all position wire, supporting all welding positions vertical, flat, horizontal, overhead.

The T means this wire is a flux cored wire

-11 is the use-ability characteristics. DC polarity, all position, multi pass

The GS – means this wire is a general wire suitable only for single pass welding.

Preparing your work piece

Although Flux cored wire welding is more tolerant of ‘dirty’ steel you will do yourself a favor by cleaning off as much rust, paint and oil from the weld joint that you can.

Using either a metal brush or grinder.

Also remember to clean where your grounding clamp connects to the work piece. The cleaner the metal and the well grounded your ground clamp is the better your weld will be. Welding is an electrical process and good electrical connections are important to successful welding.

Flux Core Wire Welding Mild Steel

Flux Core Wire Welding Mild Steel

Using Mild Steel Flux Cored Wire in your Welder

  1. Should your welder be a MIG welder and you can swap between solid wire and flux core wire, be sure to use the right drive roll for welding flux core wire. Knurled drives rolls grip the flux cored wire better and feeds the wire to the MIG gun smoothly.
  2. While you are at it, if you have a MIG welder and are swapping between flux cored and solid wire check and change the polarity.
  3. Check and ease off the wire tension in your welder when moving between solid wire and flux core wire. Flux cored wire has a soft center and too much tension will squash and distort the wire leading to feeding and welding problems.
  4. Use the right diameter on the drive rolls slot for the diameter of wire you are feeding. Using 0.030 wire use the 0.030 side of the drive roll and double check if you are getting feeding problems.
Knurled Drive Roll

Knurled Drive Roll

  1. Match the contact tip size to the mild steel flux core wire diameter you are using. 0.030 contact tip with 0.030 wire.
  2. Match the wire diameter with the gauge of mild steel your welder recommends. for example 0.030 mild steel flux cored wire could weld 18 gauge up to 1/4 inch depending on the power/Amp your welder is able to produce.
  3. Choose the size of spool your welder can feed. A 2 lb. spool = 4 inch spools. A 10 lb. spool = an 8 inch spool. If you are only welding with flux core a little and occasionally although the cost per lb. is cheaper with a 10 lb. spool, you will have to properly store the wire you don’t use. You may be better off with 2 lb. spools if you can’t store the wire well.
  4. Remove and store unused wire when you have finished welding. You really don’t want a massive clean up job when your wire has rusted in your welder when you come back months later to do some welding.

Storage of Flux Cored Wire

  • Protected from the air in particular moisture. Mild steel flux core wire will
  • rust with exposure to the air.
  • Store somewhere at a temperature similar to where you weld as even moving wire from a very cold storage place to your much warmer weld site can cause condensation inside the packaging.
  • Condensation or rust will cause you wire feed problems and difficulty striking an arc for your welding.

Mild Steel Flux Cored Wire Polarity

Mild steel flux cored self shielding wire needs DCEN (direct current electrode negative). This means your MIG gun connected to the negative terminal. Flux core only welders are set up this way by default. Should you have a MIG welder that will also weld with shielding gas you will need to remember to change over the polarity from DCEP to DCEN.

Last Words

I trust you enjoyed my article ‘Best Flux Cored Wire for Mild Steel Why These Are the Boom’. And found the above advice useful to help you choose and understand the answers to the more popular questions surrounding the use of flux cored wire.

I have a document on the site that explains the flux core welding process in greater detail. If you are flux core welding it’s good to understand more about the principals of the process. It’s called “What is Flux Core Welding for Beginners and Everyone Else“. You can use the link.

And if you want to learn more about flux core welder machines generally then check out my article “What is a Flux Core Welder? Learn Exactly in 10 Minutes“.

I wish you well with your welding projects.



Other Resources

Flux-Cored Wire Selection

Start with the Basics: Understanding Flux-Cored Wires

FCAW-G Electrode Usability Designators

Product Data Sheets/Wire Welding Parameters



INETUB Data Sheet

Blue Demon E71T-GS

Lincoln Electric NR-211-MP

Hobart Fabshield E71T-11