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How to Clean Metal Before Welding

Published October 3, 2026 · Built by Jeremy Panasuk

Cleaning is not one chore. A coating that can make toxic fume is an OSHA step. Rust and dirt are an electrode choice. Oxide on aluminum is a different metal and a different article, how to weld aluminum. This page is about steel: what has to come off before the arc, and what this site’s stick function does when you tell it the steel is still dirty.

Coatings that can become fume

OSHA’s fact sheet on welding fume says welding surfaces should be cleaned of any coating that could potentially create toxic exposure, such as solvent residue and paint. Zinc is on the list of metals that show up in welding fume. The controls around that sentence are not “wipe it and weld.” OSHA also says to position yourself so you are not breathing the fume, to use general ventilation and local exhaust, not to weld in a confined space without ventilation, and to use respiratory protection if work practices and ventilation do not reduce exposures to safe levels. Workers who get eye, nose, or throat irritation, dizziness, or nausea should leave, get fresh air, and obtain medical attention. Galvanized steel is the case that needs the full wording, on how to weld galvanized steel safely. Removing a stripe of paint does not retire those paragraphs.

Which electrode Lincoln ties to the surface

Lincoln’s classification notes sort electrodes by the metal you actually have, not by a single “welding rod.” E6011 is described for all-position AC welding and for rusty, dirty, less-than-new metal. Lincoln calls it a first choice for repair or maintenance when DC is unavailable, and says it has a deep, penetrating arc. E6010, DC only, is described as the most penetrating arc and as able to dig through rust, oil, paint, or dirt. E6013 is the one Lincoln ties to clean, new sheet metal, with a softer arc. E7018 is the low-hydrogen electrode, usually DC, used when quality is the issue or the metal is hard to weld. Lincoln’s technique note for that family is to drag the electrode lightly. Low-hydrogen electrodes rely on the molten slag for shielding, so a long arc, whipping, leaving the crater, or moving too fast can cause porosity. On a multiple-pass weld, clean the slag after each bead.

The practical split this calculator can show is the one it actually codes: clean metal maps to 7018, and rusty, painted, or dirty metal maps to 6011. It does not offer 6010 or 6013. If your procedure names one of those, the Lincoln page is the description. The calculator will not invent a window for an electrode it does not contain.

Worked example: 1/4 inch, clean, then rusty

One-quarter inch is 250 mils. On the stick tab, enter 250 and choose clean. Half of 250 is 125. That is above 66 and above 100, and it is at or under 128, so the diameter is 1/8 inch. Clean selects E7018. The stored window for 1/8 inch E7018 is 90–140 amps. The power-class line says a 120 volt machine is OK, because 140 amps is the top of that window and the top of the Handler 140’s published range on 115 volts. The line follows the rod window, not the 250-mil thickness. The 7018 note in the function says DCEP only.

Change only the condition, to rusty. Thickness stays 250. The diameter stays 1/8 inch, because diameter comes from thickness, not from rust. The electrode flips to E6011, and the stored window for 1/8 inch E6011 is 75–125 amps. Power class stays “120 V machine OK,” because 125 amps is also inside 25–140. Same plate, same rod diameter, different process family and a lower amp window.

That is the calculator’s whole opinion about dirt. It does not tell you how far back to grind, what grit to use, or whether mill scale is gone. Those details are not in the sources this page is willing to cite, so they are not filled in. What the sources do say is: get coatings that can create toxic exposure off the surface, match 6011 to metal that is still rusty or dirty, and do not run 7018 with a long arc or over slag you did not chip.

A common mistake

The mistake is leaving the condition on “clean” because the plate is thick. Thickness picked the 1/8 inch diameter. Condition picked 7018 versus 6011. A rusty 1/4 inch joint run as 7018 at 90–140 amps is the calculator being lied to. Lincoln’s reason for 7018 is quality on metal that can support a low-hydrogen bead. Rust, paint, and oil are the duty Lincoln assigns to 6010 and 6011. The other mistake is treating a ground stripe as permission to ignore OSHA’s ventilation lines. Paint and zinc are fume sources until the controls, not just the grinder, are in place.

Limits

Chip slag between passes when you are on 7018, as Lincoln says, and confirm the bead on scrap. A structural or code joint that specifies an electrode and a cleaning distance is that specification, not this menu. If you cannot tell paint from galvanizing, assume a coating and use the galvanized page before any amp. This calculator will still print a number for dirty steel. The number is a rod window. It is not a statement that the fume is acceptable.

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E6011 welding rods

Compiled with AI assistance from the sources below. Spot an error? Email [email protected].

Sources

• OSHA, “Controlling Hazardous Fume and Gases during Welding,” Fact Sheet DSG FS-3647 (March 2013). https://www.osha.gov/sites/default/files/publications/OSHA_FS-3647_WELDING.pdf. Accessed October 3, 2026.
• Lincoln Electric, “AWS Classifications.” https://www.lincolnelectric.com/en/welding-and-cutting-resource-center/process-and-theory/aws-classifications. Accessed October 3, 2026.
• Lincoln Electric, stick electrode welding guide (technique notes for EXX18 electrodes). https://harrisweldingsupplies.com/content/catalogs/lincoln-stick-electrode-welding-guide.pdf. Accessed October 3, 2026.