Tips On How To Weld With A Flux Core Welder

Before we go deep into the tips on how to weld with a flux core welder, it is important to go through problems that may arise during the process.

 Below are the most common problems that arise in flux core welding and how to avoid them:

Wire Feed Stoppages

This is a very common problem experienced by most welders. These malfunctions can cause a lot of time wastage. The two common wire feeding problems are:

1. Burn back: This happens when the wire feeding speed is slow. The flux core welding wire melts into a form of a ball on the contact tip.

This can also be caused by positioning the gun too close to the metal being on. To prevent this from occurring, ensure that you feed speed is correct and maintain distance of 1 ¼ inch.

2. Birdnesting: This happens when the arc is extinguished prematurely. To prevent this from happening use V or U groove drive rolls in the wire feeder. This occurs when a wire is tangled hence hindering wire from being fed.

Birdnesting can also be caused by blockages in the inner liner or usage of a wrong liner.

 Conduct a routine inspection on your welding gun and ensure that you use the correct tools to trim the liner. The liners shouldn’t have any sharp edges.

Prevent Porosity And Worm Tracking

Porosity occurs as a result of gas being trapped in the weld metal. This makes a weld look bad. Ensure that your metal is free from grease, oil, rust, paint and moisture to prevent porosity. Use thee correct electrode and the wire shouldn’t go beyond 1 ¼ inch from the contact tip.

Worm tracking is a common problem just like porosity. To avoid worm tracking, use the correct voltage recommended for your wire feed and amperage.

Slug Inclusions

This usually happens when the slag generated by the molten flux is trapped inside the weld. To avoid the following tips might help:

  • When making multiple passes avoid incorrect bead placement.
  • Use the correct travel angle and speed.
  • Use proper heat output.
  • Use your chipping hammer, brush or grinder to clean your weld before welding again.

Avoid Undercutting

Avoid deep penetration or lack of penetration. Use the appropriate heat output to avoid excessive penetration or less penetration.

We have gone through common mistakes that might occur during flux core welding projects. Let’s dig into tips on how to weld with a flux core welder.

8 Tips On How To Weld With A Flux Core Welder

1. Equipment

Gather all your equipments together before you start working. The most important of all your safety gears should be at the top. These are:-

  • Glasses – They are very important because they prevent damage on your eyes. The UV light can be very dangerous thus it’s important to have glasses.
  • Welding mask
  • Welding leather boots
  • Leather apron or overalls
  • Ear protection
  • Gloves
  • Pliers
  • Chipping Hammer
  • Wire brush
  • Fume extractor
  • Metal Ruler
  • Welding Machine

2. Cleaning

Ensure that your metals are cleaned. They should be free from dust, oil, paints, rust and moisture. Use the wire brush and the grinder with a wire wheel to do the cleaning.

Removing contaminations ensures that your weld is of high quality. Before cleaning secure your work piece with C clamps because the

3. Cut The Metal

Before cutting the metal, ensure that your measurements are of correct lengths. Start by making a mark on the metal piece using the soap stone and the metal ruler.

Ensure that you’ve clamped the work piece so that it doesn’t move when cutting.

4. Work Piece Setup

For you to be able to weld your work piece appropriately, set it up before you start to weld. You can use a magnet to ensure that your work piece stays in place. Double check your work piece before you lay your first weld. Planning is very important here, welding loose metals will frustrate your flux welding project.

5. Adjust The Welder Settings

You can have everything planned out well but if this step is left out, an end result will be a bunch of mistakes. Ensure that you adjust the flux core welding settings to fit your needs.

 If you’re welding a thick metal, increase the voltage and the wire speed. Read the suggested settings if you have no idea on what settings suit you.

6. Weld The Work Piece

After adjusting the setting on your welder, start by tack welding each corner of the metal together. When doing this, ensure that you fuse both sides of metals together.

Hit the metals where they come in contact with each other. When you focus on one metal than the other the end result will be lack of fusion. This leads to metals being joined poorly.

 Use the wire brush to clean the welded area so as to remove slag. Slag comes from the tack weld. After you’ve confirmed that the corners are tacked together, the work piece will now take the intended shape. Check for mistakes and fix them immediately.

7. Fill In The Remaining Seams

Use bead welds to fill in the remaining areas. Maintain consistency in travel speed, torch angle and electrical stick-out because they affect your weld’s appearance. Travel speed should be constant and fast.

Don’t change the speed a mid weld. Maintain electrical stick-out of 3/8”. If your weld comes out ugly, be patient and practice.

8. Cleaning Again

Now that you’re done with your welding, it’s time to remove that slag left. Use the wire brush and the chipping hammer to remove the slag. This slag is usually left by flux.

Use the pliers to clamp the edges of your weld. Take the grinder and use it to remove the outer layers of the work piece. Aim to end up with a seamless transition that doesn’t have any holes and cracks.

If you notice any defects, you can re-weld your work piece and clean it again.

Final Word

Many constructions use the flux core welding technique. It is reliable and can bring forth quality welds. If you combine your basic skills and master the art of solving malfunctions then you can easily become a pro.


Edward, a seasoned welding expert, shares his extensive knowledge and insights on to help you enhance your welding skills. is reader-supported. When you purchase through links on our site, we may earn an affiliate commission at no additional cost to you. See affiliate disclaimer.