The Fabricator - August 2009

A A Welding Tips

Stick welding:

Tips for top performance

5 steps can help a

welder avoid getting stuck with poor welds

By Brad Hemmert and

Amanda D’Arcy

For those who are new to it or perhaps who don’t weld every day, stick welding—also known as shielded metal arc welding (SMAW)—is one of the more difficult processes to learn. Experienced welders who can pick up a stinger, pop an electrode in, and lay down great welds time after time can inspire great awe in other welders. They make it look easy.

The rest of us may struggle with it, however. That doesn’t have to be the case if you pay attention to five basic elements involved in establishing a good, consistent technique:

1. Current setting

2. Length of arc

3. Angle of electrode

4. Manipulation of electrode

5. Speed of travel

Together, this is known as CLAMS. Properly addressing these five basic areas can improve your stick welding results.

Preparation Prevents
Aggravation

While stick welding may be the most forgiving process on dirty or rusty metal, don’t use that as an excuse for not properly cleaning the material. Use a wire brush or grinder to remove dirt, grime, or rust from the area to be welded. If you don’t, you’re hurting your chances to make a good weld the first time. Unclean conditions can lead to cracking, porosity, lack of fusion, or inclusions.

The FABRICATOR® | An FMA Publication www.thefabricator.com | August 2009

While cleaning the material, make sure you have a clean spot for the work clamp. A good, solid electrical connection is important to maintain arc quality.

Next, position yourself so you have a good view of the weld puddle. For the best view, keep your head off to the side and out of the smoke; this gives you a clear view to ensure you’re welding in the joint and keeping the arc on the leading edge of the puddle. Maintain a comfortable stance so that you can support and manipulate the electrode with ease.

CLAMS Takes Time to Learn

Pulling all the CLAMS points (current setting, length of arc, angle of electrode, manipulation of the electrode, and speed of travel) together may seem like a lot to think about while welding, but it becomes second nature with practice. Don’t get discouraged. After all, learning to stick weld requires a learning curve. Everyone sticks the electrode to the workpiece in the early days—leading most to wonder if that’s how the process got its name.

Current Setting. The electrode you select will determine whether your machine should be set up in DC positive, DC negative, or AC. Make sure you have it set correctly for your application. (Electrode positive provides about 10 percent more penetration at a given amperage than AC, while DC straight polarity, electrode negative, welds thinner metals better.)

The correct amperage setting primarily depends on the diameter and type of electrode you select. The elec-

CFIGURE 1 Unless the electrode manufacturer states otherwise, use 1 amp for each 0.001 in. of electrode diameter. Here a 0.125-in. electrode is used, so the operator starts at 125 amps. Adjustments are made in 5- to 10-amp increments, if necessary, to find the optimal setting for his technique and application.

CFIGURE 2 If you’re welding with amperage set too low, your electrode will be especially sticky when striking an arc, and you’ll be unable to deliver a smooth weld.

CFIGURE 3 When the amperage is set too high, the puddle will be excessively fluid and hard to control. This can lead to excess spatter and higher potential for undercut.

Length of Arc. The correct arc length varies with each electrode and application. As a good starting point,

arc length should not exceed the diameter of the metal portion (core) of the electrode (see Figure 4). For example, an 0.125-in. 6010 electrode is held about 1⁄ 8 in. off the base material. Holding the electrode too closely to the joint decreases welding voltage. This creates an erratic arc that may extinguish itself or cause the electrode to freeze faster. The result is a weld bead with a high crown (see Figure 5).

Excessively long arcs (too much voltage) produce spatter (see Figure 6), low deposition rates, and undercuts, which is when the area outside of the weld is concave or recessed. Long arcs also often leave porosity.

When first attempting to stick weld, it seems natural to use a too long arc, possibly to help get a better view of the arc and puddle. If you have trouble seeing, move your head, don’t lengthen the arc. Start by finding a good body position that gives you an adequate view of the puddle, while also allowing you to stabilize and manipulate the electrode. A little practice will show you that a tight, controlled arc length improves bead appearance, creates a narrower bead, and minimizes spatter.

trode manufacturer usually indicates the electrode’s operating ranges on the box or in enclosed materials. Select your amperage based on the electrode (see Figure 1), welding position (about 15 percent less heat for overhead work compared to a flat weld), and visual inspection of the finished weld. Adjust your power source by 5 to 10 amps at a time, until the ideal setting is reached.

If your amperage is too low, three scenarios may occur:

• Your electrode will be especially sticky when striking an arc

• Your arc will keep going out while maintaining the correct arc length

• Your arc will stutter (see Figure 2)

Once you get an arc going, if the puddle is excessively fluid and hard to control, your electrode chars when it’s only half gone, or the arc sounds louder than normal, your amperage might be set too high (see Figure 3) . Too much heat also can affect the electrode’s flux properties negatively. If the electrode starts to glow, you have a problem.

CFIGURE 4 The optimal arc length, or distance between the electrode and puddle, is the same as the diameter of the electrode (the actual metal part within the flux covering). CFIGURE 5 An arc length that is too short could lead to the electrode sticking to the base material.