Introduction: Basic Guide to Flux Cored Arc Welding

Picture of Basic Guide to Flux Cored Arc Welding

Hello and welcome to the SLO Makerspace guide to Flux Cored Arc Welding! This Instructable is intended to teach you how to use the Lincoln Weld Pak HD flux cored arc welder. This machine is one of the most basic welders available on the market today and is known for being both user-friendly and cost efficient. Although there are several limitations as to what you can get away with welding on this machine, it is a great welder for beginners and is perfect for doing non-structural, ornamental welding.

Here are some Weld Pack HD product specifications provided by Lincoln Electric:

  • Welds mild steel with a gasless, flux core wire electrode
  • Welds up to 1/8 in. mild steel
  • Plugs into household 115V, 20 amp outlet
  • 35-88 amps output
  • Cold contactor safety feature keeps welding wire electrically cold until the gun trigger is pressed

For more information in regards to this particular welder, please read the operator's manual: HERE

The first and most important thing to consider while using this machine is... you guessed it, SAFETY! Not only is the electricity required for arc welding extremely hot, but it also generates dangerous UV light that can easily damage your eyes if you look directly at it. This is why you should always use the proper Personal Protection Equipment (PPE) while working on your welding project. This includes, but is not limited to: safety glasses, leather welding jacket, welding gloves, and of course, the welding mask (also known as a welding hood). It also really helps if you have long pants and close-toed shoes. Flux Cored Arc Welding (FCAW) is known to generate lots of sparks that can easily burn any unprotected areas of your body, so cover up! These sparks can also easily start a fire so any flammable materials should be kept at a reasonable distance from the welding area.

That being said, welding can be a fun and exciting way to make things out of metal and after a bit of practice, there is endless potential to make some really cool stuff, so lets get started!

Step 1: Gather Necessary Equipment

Picture of Gather Necessary Equipment

Before you start welding you will need to make sure you have all the tools required for the project at hand. The following list should contain everything you will need over the course of your welding project:

  • Safety Glasses
  • Welding Mask
  • Gloves
  • Leather Jacket
  • Ear Protection
  • Pliers
  • Chipping Hammer
  • Wire Brush
  • Grinder with cutting/grinding/wire wheels
  • Clamps
  • Magnets
  • Tape Measure/Metal Ruler
  • Fume Extractor
  • and if course, the Welder!

Step 2: Clean Your Metal

Picture of Clean Your Metal

Although FCAW is known for being a process that can get away with welding dirty metal, it is still important to clean the area of the metal you plan on welding. This is generally done with some sort of wire brush, grinder, or even better, a grinder with a wire wheel. Removing contaminates such as rust or paint will drastically increase the quality of your welds, so taking the time to clean up your project before you start welding is always a good idea.

Prior to taking the grinder to your work-piece, you should always take steps to make sure the metal you plan on grinding is secure. This generally done with clamps, preferably not spring clamps as they don't always exert the necessary force required to keep the metal in place while grinding on it. Personally, I like to use either the table vice or a C-clamp, as they allow you to control the amount of pressure being applied to the work-piece.

Once the metal is secure, you are free to grind away until you have removed the majority of whatever it is that is getting in the way of the bare metal that is necessary for a good weld.

*Reminder: While grinding, be sure to direct any sparks in a safe direction (i.e. not towards a person or a flammable object)

Step 3: Cut Your Metal

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In addition to welding metal that has been sufficiently cleaned, you should also make sure your metal has been cut to the appropriate length. Correctly cutting your metal can be equally if not more difficult than the actual welding, depending on what you are working with.

An accurate cut starts with accurate an accurate scribe, or mark, on the work-piece. This is generally done with a soap stone or sharpie, and a ruler with a straight edge. For this demonstration I've chosen to keep it fairly simple and make a 2" x 2" x 2" container out of sheet metal. Therefore, I will need 5 2" x 2" squares in order to complete my project. I first scribe a line 2 inches away from the edge of my sheet metal, going all the way across it. Then, I scribe a series of vertical lines going from the edge of the sheet metal to my first scribed line until I have 5 squares drawn in sharpie on my work-piece. Now I am ready to cut!

When cutting extended lengths of sheet metal it is a good idea to use some sort of guide to ensure a straight cut. I decided to use a long piece of square bar stock to help me maintain my first, and most important cut. After that I just did my best to follow my scribe lines and thankfully they turned out alright. For each cut you should clamp the work-piece down so that it doesn't go anywhere once you begin cutting.

Step 4: Set Up Your Work Piece

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Once you have cleaned your metal and cut it to the appropriate dimensions, it is time to get your work-piece set up so that you can easily tack-weld it together without having to fight with it too much. For mass production work, this is where you would typically devise some sort of jig that would allow you easily to set your pieces into place without having to think about it. For this project, I'm just going to use a magnet with a 90 degree angle in order to make sure my square container doesn't turn into a trapezoid container.

Making sure that the pieces you plan on welding together are secured in the exact position you plan on welding them is extremely important. Welding loose materials can lead to countless mistakes and can add unwanted extra work to your project, so make sure to double and triple check your work-piece before you lay down your first tack weld. After you've lined everything up accurately, it is time to start welding!

Step 5: Turn on Welder and Adjust Settings

Picture of Turn on Welder and Adjust Settings

Of course, adjusting the welder to the appropriate settings is another essential part of this project. Since the sheet metal for our container is a fairly thin gauge (approx. 1/16"), I will be welding on the LOW 1 setting with the wire speed set to 7. As the metal you are welding increases in thickness, you will want to increase the voltage and wire speed as you see fit. It is always good to do a couple test welds on some scrap metal to make sure your settings are right where they need to be before you actually start on your project.

If you are unsure about what settings you should use for your own project, refer to the "suggested settings" section of the welding parameter image that has been provided.

For additional tips, the last four sections of that same image give some valuable information on proper technique while welding.

Step 6: Tack-Weld the Work Piece

Picture of Tack-Weld the Work Piece

After you've got everything lined up correctly and set your welder to the appropriate settings, tack-weld each corner of your work piece together. When tack welding, it is important to make sure that you are actually fusing both sides of the metal together. When you pull the trigger on the torch, pay attention to where you are depositing the weld metal and that you are hitting the work-piece exactly where one piece comes in contact with another. Welding one side more than the other will lead to a lack of fusion which can result in the two pieces of metal not joining together properly. Remember to clean up the area you just welded with the wire brush to remove any slag generated from the tack weld.

Ideally, once you have tacked each corner together, the box will have taken shape and you will be able to see if each side is aligned and welded into the right position. If not, now is the time to fix your mistakes, as they will be much harder to correct after you finish welding!

Step 7: Fill in the Remaining Areas With 'Bead' Welds

Picture of Fill in the Remaining Areas With 'Bead' Welds

Assuming that you tacked everything together correctly, you can now go back and fill in the remaining seams with bead welds. This is where you will really get to hone in your welding skills, so pay close attention to how your torch angle, travel speed, and electrical stickout affect the appearance of your welds.

The most important thing to consider while performing these welds is maintaining consistency in the above categories. In other words, once you've figured out the proper torch angle, don't change it mid-weld. Your travel speed should be fairly fast, and you don't want to speed up or slow down mid weld, but maintain a constant pace. Lastly, your electrical stickout should never be more than 1/2" or less than 1/4", so keeping it at around 3/8" will be your best bet.

Mastering the consistency of your welding technique is the key to being able to weld proficiently, and it's going to take some practice before your welds come out looking perfect. Keep this in mind if they don't look great on your first try, just be patient remind yourself that practice makes perfect!

Step 8: Clean Up Your Piece

Picture of Clean Up Your Piece

After you've welded everything together, there is going to be a bunch of spatter and slag left over from the flux. Now is the time to use the chipping hammer and wire brush to remove as much of this as possible before we start grinding.

Once you've removed as much as you can by hand, grab your pair of locking pliers and clamp it to one of the outside edges of the container. Carefully use the bench grinder to grind down your welds until you've basically removed the outer layers of your weld and the corners are flush with the sides. While grinding, make sure you keep the work-piece safely rested on the guard. You will probably have to re-clamp your locking pliers once or twice in order to effectively grind each corner. If you welded the edges correctly, each corner should look like a seamless transition on each side and should be free of any holes or cracks. If not, you may need to go back and re-weld the areas with defects and repeat the cleaning/grinding process until you reach the desired results.

At this point you are basically done with your container! If you still aren't satisfied with how it looks you are welcome to add your own modifications like a lid, or maybe some paint. Great job!

Step 9: Clean Up the Area

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Pretty self-explanatory.. Clean up the area you were working at and put all the tools back where you found them.

Thank you!

Step 10: Profit!

Picture of Profit!

Once you're comfortable welding, try to get creative and make something awesome like this robot!


kbbaktha (author)2017-12-03

very informative for a novice like me, who is planning to enter into this hobby. Thanks for such a nice instructables.

daybyday2k75 (author)2017-02-08

Would you specify about the placement of the Welder's grounding electrode? I did not see where it was placed in this example? Does it attach to the metal table my workpiece is resting on or does it clamp directly to the workpiece I am welding? Thanks!

Usually the rule of thumb is closest u can get the ground the better if its possible attach the ground to the work piece usually i likento make a nice shiny corner specifically for attaching my ground

Thanks for your interest. There are different reasons to do either. While it is very common practice to just attach the clamp to the table, do be careful to make sure that your work piece has a good contact with the table. If it is light, can roll or otherwise move around, be sure to clamp it to your table. This is a serious point of safety. Welding can be very dangerous, stay safe!

BertonP (author)2016-08-24

Step number nine is the most imortant.

roccitman (author)BertonP2016-10-30


Marsh (author)2014-10-27

Very good effort. Well presented!
About that vacuum cleaner though. Never use a vacuum clean as a fume extractor for welding. Ever hear of a dust explosion? Suck a hot spark into a vacuum cleaner tank and you may get to see one first hand.

SLOMakerSpace (author)Marsh2014-10-29

The fume extractor pictured is not a vacuum cleaner. It is a portable fume extractor made by Lincoln Electric. Thank you for the input though, I'll keep that in mind if I ever catch somebody trying to use the shop vac to extract welding fumes!

Marsh (author)SLOMakerSpace2014-10-29

Sorry man. Totally looked like a shop vac to me.

briquettemachine (author)Marsh2015-12-12

i know lincoln electric company. i am from china and this company has a branch in our city. but i am only engaged in produce welding wires & fluxes for submerged arc welding process. But still, i think this article is really helpful to me. It brings more knowledge about welding to us. To know more about welding fluxes.

AdeelR (author)2015-10-06

Excellent Article on this forum. FCAW process was introduced as a combination of Stick and MIG process for those welding jobs that require specific conditions common in both processes. Besides suitable welding parameters, the maintenance of flux wires is another major factor to produce quality welds. you can find further useful information on FCAW process here

YvonL (author)2015-06-18

I'm sorry to hear that mikecz, I knew that you had to take some precautions after having a pacemaker, but I had no idea at the extent or variety of risks. Is there any reason why arc welding is a problem and does that include other types of welding? I am in an auto shop class right now, and we are just learning about welding, it's pretty fun, and I'd hate to have to avoid it all the time.

Yvon Lebras |

mikecz (author)2014-10-26

BEWARE!!! Just last week they put a heart pacemaker in me. (So far, so good with the pacemaker.) But, AFTER they put it in they tell me:

No arc welding ! (Don't even get close!)

Don't stand/lean over a running engine!

Don't play with commercial or even ham radio transmitters!

Don't stand near radar units! (Guys are putting them on pretty small boats now.)

Hold your cell phone in right hand (pacemaker in upper left chest).

I guess I really needed the pacemaker, but still, I wish they would have told me all these problems with the things BEFORE they put it in me!

gadjetramjet (author)mikecz2014-10-26

Something else, sort of related, do not have your cell phone on you or near the are you are welding, you WILL be buying a new one! I'm on my third! The plasma arc of the weld, (inductive energy) puts off a great deal of radio wave energy which blows the sensitive receiving section of your phone. (yes, a very simplified explanation) I didn't think you would all want the really technical explanation. It's the same reasons for the pace maker, etc.

IanM6 (author)gadjetramjet2015-01-30

thats a bunch of bull unless it applies to some type of extremely old technology.

i've been welding for years with phones in my pocket, samsung lg, galaxys s1 s2 s4, etc never had a single one fail and i've spent the better part of a week on welding projects. never take my phone out of my pocket and the weld table is about waist height. that include SMAW, GMAW, TIG, plasma cutters, all electrical processes. never had a problem, it equates to the same warning abouts using cell phones on airplanes.

LordBug (author)gadjetramjet2014-10-27

Hmm, the only trouble I've had with having my phone near the arc when welding is a bit of spatter creating a new (albeit tiny) crack on my screen.
What phones have you had issues with? I've been fine around MIG, stick and plasma cutting, HF start TIG would be the only one I can really see causing a problem.

gadjetramjet (author)LordBug2014-10-27

Samsung and LG, I leave the cell phone "away" and generally off now when I'm welding. Albeit, there may be a difference, I use a larger Stick Arc welder at the same times as the MIG (or flux) (depending on what I'm doing) and plasma cutter, so that might have something to do with it ... generally, up to 1/2" steel, so there would be "more" and "stronger" RIF plasma arcs

mikecz (author)gadjetramjet2014-10-26

WOW! So they are REALLY serious about not getting sensitive electronics (my pacemaker. your cell phones, etc) around welding arcs!

fidgety2 (author)mikecz2014-10-27

i have been welding for 25 plus years and have never had a phone die due to arc exposure imo this is rediculous

Phil B (author)2014-10-23

I appreciate this. A number of people I know would benefit from having and using a welder, but hold back for various reasons.

Some of the pictures have not loaded. If your picture files were a megabyte or so, could you repost them at 100 to 200 killabytes?

MIG means metal inert gas and implies a shielding gas covers the weld until it cools. Flux core has a chemical composition powder in the center of the welding wire, and it cover the weld to protect it from exposure to air before it cools. Technically, your welder is not a MIG welder, but a Flux core welder.

hiboyford (author)Phil B2014-10-26

Depending on how this welder is set up it can be a MIG or a FCAW. It all depends on what wire is use. I have 2 of these one is set up as a MIG welder for stainless work, the other is set up for carbon steel this one also has access to gas in case I need to weld in a Double shielded condition. These small welders do most anything a small shop/hobbyist needs to do.

Phil B (author)hiboyford2014-10-27

The Lincoln Weld Pak HD, which is what this welder is according to the photo, is flux core only with none of the necessary equipment or capabilities for adding shielding gas.

hiboyford (author)Phil B2014-10-27

Sorry I use Weld Pac 140HD which are gas capable

Phil B (author)hiboyford2014-10-27

I am not that familiar with Lincoln machines and had to do some on-line checking. I do believe there is a difference between the simple HD and the 140HD. As you well know from personal experience, your 140HD is equipped for shielding gas. Having said that, the "HD" lists for $269 at Home Depot. I would love to get a MIG machine for that price!

hiboyford (author)Phil B2014-10-27

I have a cheap MIG that I bought at harbor freight, it does a good job for what it cost. I think it was around $290 plus I had a 20% off coupon but it is a 240 volt unit not a 120 volt. I bought both of my 140hd's on Craigslist for $500 plus there was a bunch of other welding stuff and tools. Deals are out there just gotta be patient an keep at it. I have a decent amount of tools and almost all have been used.

seamster (author)Phil B2014-10-23

The photos should be loading correctly now. (It was an problem on the site.)

PurplePeople (author)seamster2014-10-23

Phil B is right... unless your setup has a pressurized tank with a shield gas (such as argon or a mixture of argon/CO2), you really should remove the term "MIG" from your tutorial.

hiboyford (author)PurplePeople2014-10-26

FCAW can also use Pressurized gas depending on what and how you are welding ie. outside, dirty, wet

Phil B (author)seamster2014-10-23


SLOMakerSpace (author)Phil B2014-10-24

Fixed the title in response to this comment. Thank you!

LordBug (author)2014-10-27

I'd suggest adding a mention that the FCAW process has a fairly steep learning curve compared to GMAW (aka MIG), that it is a very messy process, and that there is a definite difference between cheap no-name and more expensive name FCAW wire.

Kafukai (author)2014-10-23

Wow, this awesome for begginers.

Why didn't you used cutting electrodes instead of the grinder?

SLOMakerSpace (author)Kafukai2014-10-24

What do you mean by "cutting electrodes"? If you are talking about carbon arc gouging, we are presently not capable of that at this shop. Also wanted to use something that was easily accessible.

Kafukai (author)SLOMakerSpace2014-10-24

Not torch(plasma) cutting. The electrodes can cut/melt metal. My freind use them to disassembly buildings, instead of using the torch cutter - the gas is very expensive in my country.
My freind using Zika's electrodes( But I guess you can find more companies in the US.

SLOMakerSpace (author)Kafukai2014-10-24

Oh alright. Here in the states I believe we call this type of cutting "carbon arc gouging". It is great for cutting very thick or hard to reach areas, however the cut is usually very dirty and uneven, therefor it is inappropriate for this application. It would be nice to have access to one here at our shop, though.

LordBug (author)SLOMakerSpace2014-10-27

If you convert from gassless to gas shielded, and preferably an argon mixture over a CO2, you can use the MIG to cut. It ain't pretty, but it saves time :)

I would agree, the more straight and clean a cut is, the easier it is to weld!

bodger-bill (author)2014-10-27

I haven't actually tried this yet !, but I understand that to get the best results using cored wire, that the polarity of the leads should be reversed

I do know, that doing this when using conventional gas will allow much thinner metal to be welded, because the positive and negative leads have a 40/60% ratio, in terms of their heating power

Many years ago, we used to demonstrate this phenomenon by welding two layers of "Coke" can together, using 0.8mm wire

gadjetramjet (author)2014-10-26

A point to grinders, the smaller grinders can be purchased inexpensively, to the point they are almost disposable. I have 5 on the go for any project, Wire brush cup, 1/8" cutting wheel, standard grinding wheel, metal "sanding" style disc, wire brush, with wires brush on the horizontal axis. I rarely use a bench grinder. It is a great time saver if you do not have to keep switching discs for different tasks.

A hint for flux, the quicker you get to it the easier to chip off, I try to get to it as soon as the colour cools off, i.e. red to blue / black. Additional, do not weld over cooled flux, "ALWAYS!" clean off flux before starting a adjoining weld. Rule of thumb, if you stop, clean!

eslighton (author)2014-10-26

Does flux core welding work with 316 stainless steel?

gadjetramjet (author)eslighton2014-10-26

you are better to use "TIG" for stainless, much better looking weld.

Greg1101 (author)2014-10-26

Thank you for this.

Very good presentaion.

emachine56 (author)2014-10-26

Nice instructable for beginning wire welders. I think "aheibi" may be referring to E6010 (DC only) or E6011 (AC) stick electrodes. While designed for a deep, penetrating weld for tight fit-ups and for dirty conditions like corrosion, paint, dirt, oil in situations where proper prep may not be possible. I'm no pro but I have used both with similar results. Many consumers have an AC or AC/DC box like the Lincoln AC125 or AC 225/125 both will cut with the E601* sticks when duty cycles are observed. I know of 2 electrodes available overseas, the HILCO Cutil 4KG both designed specifically for this task...I'm sure there are many more. Great job though, keep it up!

SparkySolar (author)2014-10-24

Thank you for your nice instructable.


kakashibatosi (author)2014-10-24

I thought it was humorous that all of the welding turned into a cheerful robot at the end. I was expecting it to be just a metal box. Nice job.

donttrustthepig (author)2014-10-23

If you want really clean welds, wipe the metal down with a degreaser before welding.

seamster (author)2014-10-23

This is an excellent tutorial on welding. Thank you.

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