Weld Metal

Weld Metal Takeoffs That Protect the Bid

The weld metal takeoff drives the labor estimate and the bid. How to take off pounds accurately, apply efficiency losses, and close the loop job by job.

Filler metal is only 10 to 15 percent of welding cost, but the weld metal estimate drives everything else in the bid: arc hours come from pounds deposited divided by deposition rate, and labor is 70 to 85 percent of the job. Miss the takeoff by 15 percent on a job with 5,000 pounds of deposit and you have not just bought 750 extra pounds of wire; you have mispriced roughly 250 arc hours. Weld metal required is the keystone estimate of fabrication bidding, and it deserves more rigor than the margin note it usually gets.

The mechanics: weight of deposit per inch times total weld length, divided by deposition efficiency to get purchase quantity. A 1/4 inch fillet carries about 0.106 pounds per foot including typical reinforcement. Four hundred feet of it needs 42.4 pounds deposited; with gas-shielded flux-cored at 85 percent efficiency, buy 50 pounds. The Weld Metal Required calculator runs length, weight of deposit per inch, and efficiency in one pass, which keeps estimators from quietly skipping the efficiency division, the most common thousand dollar mistake in small shop bids.

Respect the square law. Fillet weld volume grows with the square of the leg size: a 5/16 fillet carries 0.166 pounds per foot, 56 percent more than 1/4, and a 3/8 carries 0.239, more than double. That is why a takeoff that assumes print sizes while the floor habitually welds one size over will miss by half. It also works in your favor: getting engineering to correctly size welds down from 3/8 to 5/16 where the design allows cuts metal, arc time, and distortion by about 30 percent in one stroke of a pen.

Groove welds hide their weight in the prep. A single-V in 1 inch plate at a 60 degree included angle carries roughly 30 to 35 percent more metal than the same joint beveled at 45 degrees. Every extra 1/16 inch of root gap adds a full-width stripe of metal down the entire joint length. On thick work, a double-V roughly halves the metal of a single-V. Take off from the actual WPS joint details, not generic ones, because a fit-up standard that allows 1/8 root gap where you priced 1/16 is a 10 to 20 percent metal overrun on its own.

Efficiency converts deposited pounds to purchased pounds, and it varies threefold. Stick runs 55 to 65 percent after stubs and slag, so 100 pounds of deposit needs 155 to 180 pounds of electrodes. Flux-cored runs 80 to 88, solid MIG 90 to 97, submerged arc near 99. Quote each job at the process actually planned for it. A bid built on MIG efficiency that gets welded with stick out of position eats a 30 to 40 percent consumables overrun, plus the schedule slip that comes with a 3 pound per hour process replacing an 8 pound one.

The failure modes repeat: measuring drawing lengths but missing weld-all-around symbols, both-sides symbols, and stitch weld conversions; ignoring floor overwelding, which audits typically find at 30 to 60 percent extra metal on fillets; forgetting reinforcement and root gap allowances; and never closing the loop, so the same estimator misses the same way for years. Keep a variance file of estimated versus actual pounds by job. After 10 jobs you have a measured correction factor for your own shop, which is worth more than any handbook table anyone ever printed.

Cadence: at job close, reconcile wire and electrode purchases against the estimate and log the variance with a reason code. Monthly, review variances over 10 percent with estimating and the floor in the same room, because half the gap is usually welding practice, not takeoff error. Quarterly, re-audit fillet sizes on the floor with a gauge, 20 welds per welder, and feed the real overweld factor back into the estimating standard. Within two quarters most shops move takeoff accuracy from plus or minus 20 percent to plus or minus 7.

World class estimating holds material takeoffs within 5 percent of actual on repeat work and 10 percent on new work, prices each job at the planned process efficiency, and carries a measured overweld factor per work center rather than a guess. Shops at that level bid with 3 to 5 points less contingency than competitors and still land on margin, which over a year of competitive fabrication bidding is the difference between a full shop and a busy shop that loses money.

Published 2026-07-02.