Introduction: Basic Guide to Flux Cored Arc Welding

By SLO MakerSpace, Inc.
About: SLO MakerSpace offers tools, training, and consultation services that enable community members to experiment with and master a wide variety of Maker skills. We are dedicated to the following values: Commun…

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

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

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

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

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

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

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

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

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

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!

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

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