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How to Weld

Published October 3, 2026 · Built by Jeremy Panasuk

A first weld is a sequence, not a machine slogan. Measure the metal. Decide whether it is clean. Pick stick, MIG, or TIG. Read the amp window that choice produces. Then read the duty cycle at those amps, which is minutes out of ten, not the biggest number on the box. Machine shopping for a home garage is already on what size welder for a beginner home garage and beginner welder size. This page walks one stick path through the calculator so the sequence is visible.

Start with thickness and condition

The stick tab wants thickness in mils, thousandths of an inch, and a condition: clean, or rusty, painted, or dirty. One-eighth inch is 125 mils. Lincoln describes E7018 as the low-hydrogen electrode used when quality matters, and E6011 as the electrode for rusty, dirty, less-than-new metal and for repair work. The calculator encodes that split as the condition menu. Clean selects 7018. Rusty selects 6011. If you do not know which the joint is, look at it before you open the tab. Cleaning is a separate step, and coated metal is a fume problem, not a menu choice. See galvanized steel before you strike an arc on a zinc coating.

Worked example: 125 mils, clean, stick

On the stick tab, enter 125 and choose clean. The function takes half of 125, which is 62.5, rounds it to 63, and refuses to go below 62. A result of 63 is at or under 66, so the rod diameter it prints is 1/16 inch, not 1/8 inch. Clean metal selects E7018. The 1/16 inch E7018 window stored in the function is 40–80 amps. Polarity text for 7018 says DCEP only. The power-class line says “120 V machine OK.” That line looks at the rod window, not at the 125-mil thickness. The Handler 140 spec sheet lists a welding range of 25–140 amps on 115 volts. Forty through 80 sits inside that range, so the function treats a 120 volt machine as enough for this rod.

The sheet is a MIG machine rated 90 amps at 20 percent duty cycle, so it is not itself a stick procedure. It is the published 115 volt range the voltage line is checked against. A 1/16 inch rod at 40–80 amps is a small arc. The line is not a claim that every 1/8 inch plate should be welded on 120 volts with a different, larger rod.

Then run duty cycle at the amps you will actually hold

The farm guide treats duty cycle as minutes out of a 10-minute period. Twenty percent is 2 minutes welding and 8 minutes cooling, at the amperage printed beside that percentage. The Handler 140 prints 90 amps at 20 percent. At that nameplate point you do not need the square rule: 20 percent of 10 minutes is 2.0 minutes on and 8.0 minutes off.

The duty-cycle tab applies a square rule when the amps you type are not the rated amps. Use the top of the calculator’s window, 80 amps, against the published 90 amp, 20 percent pair. The function does 20 × (90 ÷ 80) squared. Ninety divided by 80 is 1.125. Squared, that is 1.265625. Times 20 is 25.3125, which the display rounds to 25 percent. Weld time is 2.5 minutes of the 10. Cool-down is 7.5 minutes. Inputs, in order: rated amps 90, rated duty 20, actual amps 80.

The first-bead story for this joint is: 1/16 inch E7018, 40–80 amps, and a 120 volt machine whose published range includes that window, with about 2.5 minutes of arc in 10 at the top of the window if the nameplate you typed was 90 amps at 20 percent. Confirm the bead on scrap. Lincoln’s note on low-hydrogen rods is to drag a short arc and not to whip it. A long arc is how 7018 picks up porosity.

A common mistake

The mistake is shopping from the plate thickness and ignoring the rod the same click selected. One-eighth inch of steel is 125 mils, and a bigger machine is an easy guess, but this run is a 1/16 inch electrode at 40–80 amps, which the Handler sheet’s 25–140 amp range on 115 volts already includes. The other direction is just as wrong: ignoring duty cycle and welding as if the percentage printed next to 90 amps still applied at 140. For this example the top of the rod window is 80, not 140, and the duty tab moves 20 percent to about 25 percent. Run the numbers for the amps you will hold, not for the number in the product name.

Limits

This is a planning path for a practice bead on mild steel you can throw away. It is not a code weld, a structural sign-off, or a credential. Pay, training, and what BLS actually says about licensing are on how to get into welding. Getting a calculator window right does not produce any of that. If the joint has to hold a trailer, a guardrail, or a pressure part, use a qualified procedure. If the metal is rusty, change the condition input before you trust the 7018 window. If it is galvanized, stop and read the fume page first.

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1/16 inch E7018 rods

Frequently asked questions

What does the stick tab return for 1/8 inch of clean steel?

Enter 125 mils and clean metal. Half of 125 is 62.5, which the function rounds to 63 and then treats as a 1/16 inch rod because 63 is at or under 66. Clean metal selects E7018, whose 1/16 inch window in the function is 40–80 amps. The power line says a 120 volt machine is OK because that window, 40–80 amps, sits inside the Handler 140’s published 25–140 amp range on 115 volts.

What is 20 percent duty cycle in minutes?

The farm guide treats duty cycle as minutes out of 10. Twenty percent is 2 minutes of welding and 8 minutes of cooling, at the amperage printed with that percentage. The Handler 140 spec sheet prints 90 amps at 20 percent.

What does the duty-cycle tab do at 80 amps on that 90 amp, 20 percent rating?

It computes 20 times (90 divided by 80) squared, which is about 25 percent: 2.5 minutes of welding and 7.5 minutes of cooling in a 10-minute period. That is the calculator’s square rule, not a second line on the Handler sheet.

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

Sources