Welding & Fabrication worked example

Tack Weld Time at 14% repositioning and fit-check allowance: a worked example

Suppose repositioning and fit-check allowance falls to 14%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate tack weld time from number of tacks, tacks per minute, and a fit-up handling allowance.

The inputs for this scenario

  • Number of tacks to place: 24 tacks (held at the documented default)
  • Tacks placed per minute: 3 tacks / min (held at the documented default)
  • Repositioning and fit-check allowance: 14 % (the input this scenario stresses; the baseline uses 20)

Working through the calculation

  • The calculation starts from the formula this tool documents: Base tack weld time = number of tacks to place รท tacks placed per minute.
  • Required tack weld time works out to 9.12 min at these inputs, and this is the headline figure for the scenario.
  • Base tack weld time works out to 8 min at these inputs.
  • Repositioning and fit-check allowance works out to 14 % at these inputs.
  • Tacks placed per minute works out to 3 pieces / min at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where repositioning and fit-check allowance sits at 20% and the headline result is 9.6 min, this scenario comes in 5% below the baseline at 9.12 min.
  • It divides the number of tacks by the tacking rate to get base arc time, then multiplies by one plus a repositioning and fit-check allowance to give realistic tack weld time. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Required tack weld time: 9.12 min (headline result)
  • Base tack weld time: 8 min
  • Repositioning and fit-check allowance: 14 %
  • Tacks placed per minute: 3 pieces / min

Run it with your numbers

  • To rerun this with your own numbers, open the live Tack Weld Time calculator, set repositioning and fit-check allowance to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.