Working out what a rod weighs
An electrode is a cylinder of wire with a coating baked on it, and both parts can be worked out from dimensions you can measure with a caliper. A 1/8 inch core 14 inches long is 0.1718 cubic inches of wire, which at 0.2836 pounds per cubic inch is 0.0487 pounds. Add 35 percent for the coating and one electrode weighs 0.0658 pounds, which is 15.2 to the pound and 152 in a ten pound packet.
That 35 percent is the number worth measuring rather than accepting. It varies a lot between electrode types — a heavily coated iron powder electrode carries far more of its weight in the coating than a thin cellulosic one — and it is the only input that separates a rod you can count from a rod you cannot. Weigh ten, strip one back to bare wire, and the ratio falls out. Or skip all of it, count a packet, and switch the first field to the counted mode.
Three limits, and the smallest one wins
How many electrodes a welder should walk away with is set by whichever of three numbers is smallest. The quiver holds what it holds. The exposure figure on the datasheet allows so many minutes out of the oven, which at a known burn rate converts to a rod count. And the shift itself is a limit, because there is no point issuing more than the whole day needs.
At the defaults the quiver wins by a mile. Twenty electrodes at a minute and a half of arc each is half an hour of welding, while a four hour exposure figure would allow 160 of them. The clock does not start binding until somebody is carrying more than 160 rods, which nobody is. That is worth knowing because rod discipline in most small shops is discussed as though the clock were the constraint, and in practice the constraint is a leather tube on a belt. Two and a half arc hours a welder is five trips back to the oven, which is a real interruption and a real reason people overfill the quiver.
What the bin is worth
Two inches off a fourteen inch electrode is 14.3 percent of it, by length. At two welders burning 200 electrodes a shift, that is 1.88 pounds a shift in the stub bin, which at 4.50 a pound is 8.46 dollars a shift, 42.30 a week and 2,199 dollars a year across a five day week. Bringing the stub down by one inch halves it.
Nobody should chase that at the cost of running a rod down into the holder, and the length share slightly overstates it because the bare grip end carries less coating than the middle does. But it is a number most shops have never put on paper, and it is easy to check: keep the stubs for a week and weigh them.
Where the arithmetic stops
It does not know what your electrodes are, what temperature they want, how long they may be out, or whether they need an oven at all. Every one of those is a property of the electrode and of the job, printed on a datasheet and written into a procedure, and both of those outrank anything a web page could tell you. What the page does is take the hours you type in, divide by the burn rate you measured, and tell you how many rods that comes to — which is the piece of the problem that arithmetic can actually settle.
Questions people ask
How many 7018 electrodes are in a pound?
It depends on the diameter, the length and how heavily coated they are, which is why the form works it out rather than quoting a number. A 1/8 inch core 14 inches long with a coating weighing 35 percent of the core comes to 15.2 electrodes per pound. A 3/32 of the same length works out near 27, and a 5/32 near 10. Count a packet you already have and weigh it if you want the exact figure for what you buy.
How many electrodes should I take out of the oven at once?
The smallest of three numbers: what your quiver holds, what your exposure figure allows at your burn rate, and what the rest of the shift actually needs. At a 20 rod quiver, a minute and a half of arc per rod and a four hour exposure figure, the quiver is the binding one by a factor of eight. The exposure clock only starts to matter if somebody is carrying more than about 160 rods at a time.
How long can low hydrogen electrodes stay out of the oven?
That comes from the electrode manufacturer datasheet and from whatever procedure the job is being run to, and it varies by electrode type and by the conditions in the shop. This page states no exposure time and does not know yours — it takes the hours you enter and converts them into a rod count at your own burn rate. Ask whoever is responsible for the weld procedure, not a calculator.
How much welding rod does a welder use in a day?
Arc hours divided by the arc time one electrode gives. Two and a half arc hours at a minute and a half a rod is 100 electrodes, which at 15.2 to the pound is 6.6 pounds. The arc hours figure is the one people overestimate: a welder at the bench all day is rarely over three hours of actual arc, and on fit-up heavy work it can be under one.
Is the stub loss worth worrying about?
It is worth measuring once. Two inches off a fourteen inch rod is 14.3 percent by length, which for two welders at 100 rods each a shift is 1.88 pounds a shift, or 2,199 dollars a year at 4.50 a pound and five shifts a week. That is not enough to change how anyone welds, but it is enough to be worth knowing before somebody proposes a policy about it. Keep a week of stubs and weigh them.