AWS A5.3/A5.3M · Aluminum
E4043 Welding Electrode
E4043 is the covered aluminum stick electrode — a legacy repair consumable for field work where no TIG or MIG machine is available, largely superseded by ER4043 wire.
- 14 ksi tensile
- Polarity DCEP
- 2 positions
- Medium penetration
- Stick (SMAW)
What E4043 means
| Part | Meaning |
|---|---|
| E | Covered electrode for shielded metal arc welding |
| 4043 | Aluminum Association alloy 4043, nominally 5% silicon |
E4043 specifications
| AWS specification | AWS A5.3/A5.3M |
|---|---|
| Process | Stick (SMAW) |
| Form | Covered electrode |
| Polarity | DCEP |
| Welding positions | Flat, Horizontal fillet |
| Tensile strength (min) | 14 ksi (95 MPa) |
| Impact toughness | Not applicable |
| Coating / core | Salt-based flux, extremely hygroscopic |
| Penetration | Medium |
| Deposition rate | Medium |
| Slag | Corrosive salt flux — must be removed completely with hot water after welding |
| Arc character | Fast, fluid, unforgiving |
| Shielding gas | None — self-shielding |
E4043 amperage by diameter
Typical operating ranges. Start near the middle of the range, then adjust by sound and bead profile. Reduce 10–15% for vertical and overhead work.
| Diameter | Amperage range | Typical start |
|---|---|---|
| 3/32 in (2.4 mm) | 40–70 A | 55 A |
| 1/8 in (3.2 mm) | 60–95 A | 78 A |
| 5/32 in (4.0 mm) | 90–130 A | 110 A |
| 3/16 in (4.8 mm) | 120–170 A | 145 A |
Polarity: DCEP only. The reverse-polarity arc provides the cathodic cleaning that breaks up the aluminum oxide film.
What E4043 is used for
- Field repair of aluminum castings where no TIG or MIG is available
- Emergency repair on heavy aluminum sections
- Legacy maintenance work specified with covered aluminum electrodes
- Filling and building up worn aluminum parts
Base metals
- Aluminum castings
- 1xxx, 3xxx and 6xxx wrought alloys
- Repair of thick aluminum sections in the field
Characteristics
- Largely obsolete — GTAW and GMAW with ER4043 produce far better welds
- Flux residue is corrosive and must be washed off with hot water and scrubbed
- Requires preheat of 300–400 °F (150–200 °C) on sections over about 1/4 in because aluminum conducts heat away so fast
- Coating absorbs moisture very quickly — porosity is the usual failure mode
- Needs a fast, steady travel speed; the puddle gives little warning before it drops out
Storage and handling
Extremely moisture sensitive. Keep hermetically sealed and store in a heated cabinet; open only what you will use immediately.
- The flux coating picks up water from humid shop air within hours.
- Store in a heated cabinet at roughly 250 °F (120 °C) once opened.
- Damp electrodes produce gross porosity that cannot be welded out — discard them.
- Because of this sensitivity, most shops buy ER4043 wire instead and keep no covered aluminum rod on the shelf.
Welding tips
- Preheat anything thicker than 1/4 in and hold the temperature while you weld.
- Wash the joint with hot water and a stainless brush immediately after welding to remove corrosive flux residue.
- Travel fast and keep a short arc — hesitation drops the puddle through the joint.
- If a TIG or spool-gun MIG setup is available at all, use ER4043 instead; the weld quality is not close.
E4043 frequently asked questions
Can you stick weld aluminum?
Yes, with covered aluminum electrodes such as E4043 under AWS A5.3, but the results are markedly worse than TIG or MIG. The process is limited to flat position, the flux is corrosive, and porosity is common. It is a field-repair method, not a production one.
What is the difference between E4043 and ER4043?
E4043 is a flux-covered stick electrode for SMAW; ER4043 is bare wire or rod for MIG and TIG. Both deposit the same 5% silicon aluminum chemistry, but ER4043 gives cleaner, stronger, more controllable welds.
Why does aluminum stick welding need preheat?
Aluminum conducts heat roughly four times faster than steel, so heat runs out of the joint before fusion is established. Preheat of 300–400 °F on thick sections keeps enough heat in the weld zone.
Does the flux need to be removed after welding?
Yes, completely. The salt-based flux residue is corrosive and will attack the aluminum. Wash with hot water and scrub with a dedicated stainless brush.
What is the tensile strength of E4043 weld metal?
AWS A5.3 sets a minimum of 14,000 psi as-welded for E4043 covered electrodes. Bare ER4043 filler deposited by TIG or MIG typically reaches a higher value under cleaner conditions.