Solder and Flux per Sweat-Joint Takeoff
Solder for a copper rough-in from the joint count.
Example
You enter
- Joints to sweat 200
- Solder wire per joint (in) 0.75
- Solder wire diameter (in) 0.125
- Solder density (lb/in³) 0.3
- Spool weight (lb) 1
You get
- W per (in) 0.003682
- Solder to order 0.55 lb
- Spools 1
Details, formula, and sources
weight per inch = pi/4 x diameter^2 x density; solder = joints x wire per joint x weight per inch. 200 three-quarter-inch joints at about 0.75 in of 1/8 in solid wire each is 0.55 lb (one spool); a 2,000-joint job of 1 in pipe is over 7 lb, eight spools. The wire per joint is a field rule (~the pipe diameter in inches); lead-free solder runs ~0.30 lb/in^3. Flux is a separate small line.
w_per_in = (PI/4) x wire_dia_in^2 x solder_density_lb_in3; solder_lb = joints x wire_in_per_joint x w_per_in; spools = ceil(solder_lb / spool_lb).
Solder-weight identity by name (solid-wire cross-section x density x length); first-principles geometry.
The wire weight is pure geometry (a length of solid wire of known diameter and density); the field wire-per-joint rule is public practice.
Estimate. AHJ and licensed professional govern.
Field names used by the API: joints, wire_in_per_joint, wire_dia_in, solder_density_lb_in3, spool_lb, w_per_in, solder_lb, spools
- Wire per joint ~the pipe diameter in inches of 1/8 in solid wire; varies with cup depth and techniquefield rule of thumb
- Solder density ~0.30 lb/in^3 for lead-free soldersolder manufacturer