When you are choosing stick electrodes, it helps to look beyond their similar appearance. The type you choose affects how you connect it to the machine, the positions you can weld in and how deeply the weld melts into the metal. Understanding those differences makes it easier to choose an electrode that suits the job.
This guide takes you through the electrode codes and the common choices for mild steel, then explains how to select a type for the metal you are welding. It also covers what happens once the electrodes reach the workshop, from storing them and checking their condition to deciding whether they can be dried for reuse.
In this guide:
What the AWS Electrode Code Means
The code on an electrode is a useful starting point for understanding what it is designed to do. For carbon steel stick electrodes, codes such as E6013 and E7018 come under the AWS A5.1 standard. The letter and numbers tell you about the electrode, the strength of its weld metal, the positions it can be used in and its coating type.
For the common types shown below, the final digit helps you identify the coating and the current you can use. The table gives you a way to compare those types, while the full classification and the manufacturer’s instructions provide the details for the particular product.
| Final digit | Coating type | Suitable current |
|---|---|---|
| 0 | Cellulose sodium | DC electrode positive only |
| 1 | Cellulose potassium | AC or DC electrode positive |
| 2 | Titania sodium | AC or DC electrode negative |
| 3 | Titania potassium (rutile) | AC or DC, either polarity |
| 4 | Iron powder titania | AC or DC, either polarity |
| 5 | Low hydrogen sodium | DC electrode positive only |
| 6 | Low hydrogen potassium | AC or DC electrode positive |
| 7 | Iron powder iron oxide | AC or DC, either polarity |
| 8 | Low hydrogen iron powder | AC or DC electrode positive |
Common Electrodes for Mild Steel
As you compare these common mild steel electrodes, consider both the weld they produce and the positions they can be used in. Penetration describes how deeply the weld melts into the metal. The position rating needs a closer look too, because an all-position electrode is not necessarily suitable for welding vertically downwards; the product instructions will tell you what is permitted.
| Code | Current | Positions | Penetration | Typical uses |
|---|---|---|---|---|
| E6010 | DC electrode positive only | All positions | Deep | Its strong arc gives deep penetration, making it useful for the first pass in pipe joints, known as the root pass, and for some site work. The joint still needs cleaning before welding. |
| E6013 | AC or DC, either polarity | All positions | Shallow | A common choice for general fabrication, thinner metal and repairs. It is easy to start and restart and produces a smooth weld, which often makes it useful for beginners. |
| E7016 | AC or DC electrode positive | All positions | Medium | Used where the job needs low hydrogen weld metal and a higher strength rating than E6013, with AC or DC electrode positive available as the current options. |
| E7018 | AC or DC electrode positive | All positions | Medium | Often specified for structural steel, thicker sections and joints that cannot move freely as they cool. It is a common low hydrogen choice where the welding procedure calls for it. |
| E7024 | AC or DC, either polarity | Flat welds and horizontal fillet welds only | Shallow to medium | Useful for filling larger welds quickly in flat or horizontal fillet positions, as iron powder in the coating adds more metal to the weld. |
Choosing AC, DC Positive or DC Negative
Once you have chosen an electrode, the next step is to use the current type and polarity required by its instructions and the welding procedure. AC means alternating current, while DC means direct current. With DC, polarity describes which machine terminal you connect to the electrode holder, as explained below.
- DC electrode positive (DC+). With the electrode holder connected to the positive terminal, this generally gives deeper penetration. It is the connection used by many low hydrogen and cellulosic electrodes.
- DC electrode negative (DC-). Connecting the electrode holder to the negative terminal generally gives shallower penetration when used with a suitable electrode, which can help on thin metal.
- AC. The current repeatedly changes direction, which can help reduce arc blow when you use an AC-compatible electrode. Arc blow is the magnetic effect that pulls the arc away from the joint.
If you would like to understand arc blow in more detail, our guide to common MMA welding problems explains the problem. You can also compare machines in the MMA welder range.
Choosing an Electrode for Your Metal
| Metal being welded | Typical electrode choice | What to check |
|---|---|---|
| Mild and carbon steel | E6013 for general work; E7018 when its strength and low hydrogen properties are required | Choose for the strength and other properties the job requires, as a much stronger electrode is not automatically a better match. |
| Low alloy steel used at low temperatures | Nickel-containing types such as E8018-C1 and E8018-C3 | These types are chosen for their ability to resist cracking under impact at low temperatures, with the steel grade and service requirements guiding the selection. |
| 304 and 304L stainless | E308L | The L means low carbon, which helps reduce the risk of corrosion caused by changes in the steel during welding. |
| 316 and 316L stainless | E316L | Its molybdenum content helps the weld resist small corrosion pits, particularly in conditions involving salts. |
| Stainless to carbon steel | E309L | Commonly used to join stainless to mild steel, and also as an intermediate weld layer before adding a corrosion-resistant surface. |
| Unknown, difficult or high strength steels | E312 | The weld metal’s resistance to cracking makes it useful for some difficult repairs. The material and repair requirements still need to be confirmed, as it is not a universal choice for unknown steel. |
| Grey cast iron | Nickel types such as ENi-CI | The weld metal can be machined, although the repair method and control of heat are just as important to the job as the electrode choice. |
| Worn surfaces needing rebuilding | Hardfacing electrodes | Start with the hardness and wear resistance the surface needs, then consider the required number of layers and whether the finished deposit can be machined or needs to be ground. |
Cast iron needs careful heat control
With cast iron, it is important to allow for the risk of cracking as the casting heats and cools. A cold repair method uses a low current within the electrode’s recommended range and short, straight welds, typically 25 to 50 mm long, with cooling time between them to limit heat build-up in one area. Where the method calls for peening, lightly tapping each weld while it is still hot helps reduce shrinkage stress. The repair method for the casting should guide the work, alongside the electrode maker’s polarity instructions.
Choosing Electrode Size and Current
| Electrode diameter | Example current range | Typical uses |
|---|---|---|
| 2.0 mm | 40 to 70 A | Thin sheet and small repairs |
| 2.5 mm | 60 to 100 A | Light fabrication and first passes in joints |
| 3.2 mm | 90 to 140 A | General fabrication and repairs |
| 4.0 mm | 130 to 190 A | Thicker metal, filling joints and the final weld pass |
| 5.0 mm | 180 to 260 A | Heavy plate, usually welded flat |
The ranges in the table give you a broad indication of the current different sizes may need, but the range printed on the box is the one to use for your electrode. Diameter is only part of the picture: different types can need different currents at the same size, with E7024 typically using more current than E6010.
- Use a small electrode for thin sheet. Larger electrodes usually need more current, so using one on thin sheet increases the risk of melting a hole through the metal.
- The first pass often needs a smaller electrode. The electrode needs to fit into the joint gap while allowing you to control how deeply the weld melts into the metal.
- Larger electrodes are harder to control vertically or overhead. The larger pool of molten metal they create can sag or run, so use the product’s permitted sizes for the position you are welding in.
When to Use Low Hydrogen Electrodes
One reason for choosing a low hydrogen electrode is that a weld can look sound immediately after welding and still crack hours later. Hydrogen can contribute to this delayed cracking, particularly where the steel is susceptible and the joint is under stress. Used with the correct welding procedure, low hydrogen electrodes help reduce that risk.
This is why low hydrogen electrodes are often required for higher-strength steels, thick sections and joints held so firmly that they cannot move as the weld cools. Where the welding procedure specifies them, they must be used.
Keeping the coating dry is part of achieving the electrode’s low hydrogen rating. Moisture absorbed from the air introduces hydrogen during welding, so the way you store and handle the electrodes matters as well as the type you select.
You may also see an H number, such as H4, H8 or H16, on the classification. This sets a limit on diffusible hydrogen, which can move through the weld metal and contribute to cracking. H4, for example, means no more than 4 ml per 100 grams of weld metal in the standard test, with lower numbers indicating lower limits. An R shows that the coating passes a moisture-resistance test, although an H4R electrode still needs correct storage and handling. The welding procedure determines which rating you need.
Storing and Drying Electrodes
Before deciding how to store or treat electrodes, it helps to distinguish between keeping them dry and removing moisture they have already absorbed. A holding oven keeps dry electrodes warm enough to limit moisture absorption. Re-drying uses a higher temperature to remove moisture, and is suitable only for electrodes that can safely be treated that way.
| Electrode type | How to store it | Can it be re-dried? |
|---|---|---|
| Cellulosic, E6010 and E6011 | Keep sealed in a dry place at room temperature | Do not bake them. The coating needs a controlled amount of moisture to work properly, so excessive drying damages the electrode’s performance. |
| Rutile, E6013 | Keep sealed in a dry place at room temperature | Some products can be re-dried according to their manufacturer’s instructions, but the high temperatures used for low hydrogen electrodes are unsuitable. |
| Low hydrogen, E7016 and E7018 | Once the pack is open, follow the product’s storage instructions. Holding ovens or heated quivers are often set around 120 to 150°C, depending on the electrode | The manufacturer’s instructions set the temperature and time, followed by transfer to a holding oven. These settings vary between low hydrogen products. |
| Vacuum packed low hydrogen | An intact vacuum pack normally keeps the electrodes ready to use, with the pack instructions explaining how to handle them | Opening the pack starts the permitted period in open air. Follow the product’s instructions for that time limit and for any heated storage or re-drying. |
In practice, the temperature and time need to come from the instructions for the exact product. A holding oven set around 120 to 150°C can keep dry low hydrogen electrodes in that condition, but damp electrodes need the appropriate higher-temperature drying process. Leaving them in a holding oven does not replace that treatment.
If you are choosing equipment for storage or drying, our guide to welding electrode ovens and quivers explains the options. You can also browse the ovens and quivers range.
Checking Electrodes Before Welding
- Chipped or cracked coating. Discard electrodes with damaged coating, as missing sections can expose the weld to air and cause gas holes.
- Uneven coating. Looking along the electrode helps you see whether the metal core sits centrally within the coating. If it is off-centre, the arc and weld can drift to one side.
- Rust on the metal core. Discard rusty electrodes.
- Bent electrodes. Replace bent electrodes because bending can crack the coating, even when the damage is difficult to see.
- Signs of damp. If the manufacturer permits re-drying, follow its instructions for the product. Electrodes that cannot be re-dried, or whose coating is damaged, need to be replaced.
It is worth looking at the connections as well as the electrodes, particularly if the arc is unstable. A loose or dirty work return clamp, often called an earth clamp, or a worn electrode holder can be the cause. You can find replacements in our ranges of electrode holders and earth clamps.
Understanding AWS and EN ISO Numbers
When you look at an electrode pack sold in the UK, you will often find both AWS and EN ISO classifications. Each system describes the electrode through its own codes and test requirements, so the designations need to be read in full. Use the classification required for the job rather than treating the two systems as directly interchangeable.
| Material | AWS standard | EN / EN ISO standard |
|---|---|---|
| Carbon steel | A5.1 | EN ISO 2560 |
| Low alloy and high strength steel | A5.5 | Depends on the electrode: EN ISO 2560, EN ISO 18275 or EN ISO 3580 |
| Stainless steel | A5.4 | EN ISO 3581 |
| Cast iron | A5.15 | EN ISO 1071 |
| Hardfacing | Varies by product | EN 14700 |
For work covered by a welding procedure, the electrode classification specified there should guide your choice. It is also worth confirming that your supplier can provide the product documents and any certificates the job requires.
Frequently Asked Questions
What is the difference between E6013 and E7018?
For general fabrication, thinner metal and repairs, E6013 is often useful because it starts easily and produces a smooth, relatively shallow weld. E7018 has a higher strength rating and a low hydrogen coating, which is why it is often specified for structural steel and thicker sections. E7018 also needs stricter moisture control, so the choice depends on both the job requirements and how the electrodes are handled.
Can I run E7018 on an AC welder?
E7018 is classified for AC or DC electrode positive, although the particular electrode still needs to suit your machine. Some small AC welders may not provide the starting voltage it needs, so the electrode manufacturer’s recommendations are a better guide to compatibility than the code alone.
Do I need to bake new electrodes before using them?
The packaging instructions are the place to start. Low hydrogen electrodes in an intact vacuum pack are normally ready to use, while other packaging may require drying before use or heated storage after opening. Re-drying should only be carried out where the product instructions allow it. Cellulosic electrodes such as E6010 need moisture in their coating to work properly, so never bake them to remove it.
What electrode joins stainless steel to mild steel?
E309L is a common starting point for joining stainless steel to mild steel, with the exact grades and job requirements determining whether it is suitable. You may also see E312 recommended for difficult repairs, but it should not be treated as a universal substitute when the steel is unknown.
What size electrode do I need for 3 mm plate?
For many general repairs, a 2.5 mm electrode is a useful starting point. Some products run at about 60 to 100 A, but use the range printed on the box for the electrode you choose. A 3.2 mm electrode may also suit the joint if you can control the heat, so thickness is one consideration rather than the whole decision.
Why does my E7018 keep sticking when I strike?
Start by checking the current and polarity against the electrode instructions, then make sure the electrode is dry and the work return clamp has a clean, firm connection. Low hydrogen electrodes can be harder to start than E6013, so the recommended starting technique is useful here, followed by a short arc once it is established. A hot-start setting can also help by briefly increasing the current at the start.
Can you weld cast iron with a stick welder?
Yes, provided the electrode suits the casting; a nickel type is one option for grey cast iron. The repair method matters just as much as the electrode choice. A cold repair typically uses a low current and short welds of about 25 to 50 mm, allowing cooling time between them. Where the method requires peening, lightly tapping the hot weld helps reduce shrinkage stress. Follow the instructions for both the casting and the electrode.
What does the L mean in E308L and E316L?
The L means low carbon. During welding, carbon can combine with chromium and leave parts of the stainless steel less resistant to corrosion, so using a low-carbon electrode helps reduce that risk. Choose the grade specified for the metal and its service conditions.
You can browse our full range of MMA stick electrodes and other MMA welding supplies. If you would like help choosing an electrode, use the technical enquiry form to send us the metal type, thickness and any welding procedure reference.
