How do I measure a zipper's length correctly?
Measure a closed zipper from top stop to bottom stop along the chain, excluding tape overhang, with about 3 mm tolerance.
Questions on specs, materials, processes and engineering.
Measure a closed zipper from top stop to bottom stop along the chain, excluding tape overhang, with about 3 mm tolerance.
Yes: a #8 or #10 coil with heavy tape, correct stitching and a matched slider handles workwear; sharp abrasion and heat are its limits.
Waterproof zippers feel stiff because of coating friction, tight slider tolerances and deeper interlock; proper slider choice and a pull tab help.
#3 and #5 zippers differ in chain width (about 4.5 mm vs 6 mm), strength, slider size and best-fit garment weight.
Bulging after washing is a shrinkage mismatch between tape and shell, or heat deformation of the teeth. Measure before and after to separate them.
The federal phthalate rule targets toys and child care articles; plasticised pulls in that scope must stay below 0.1 percent each.
Nickel release matters because prolonged skin contact can cause sensitisation, and children's skin touches a zipper all day.
Stock-color orders typically ship in 15-25 days; custom dyeing takes 25-35 days, and new tooling can exceed 40 days.
Corners concentrate stress and are where the tape is most distorted during making-up. A split at a corner usually starts in the seam.
Snagging is usually a construction issue: lining, a seam or a loose thread is caught by the slider or teeth.
Metal zippers add corrosion, plating adhesion and finish checks, with their own strength values and salt spray limits.
Check the seller's scope certificate, the shipment quantity against certified balances, and confirm the document with the issuing body.