How raincoats are made

Stitching punches holes in a waterproof coat, so every seam then gets a strip of tape melted over it.

stations: 7
things upstream: 59
raw sources: 17
steps from the ground: 9

The short version

Modern raincoats are made from woven nylon or polyester fabric that is coated or laminated with a thin membrane. The pores are too small for raindrops but large enough for water vapor. Panels are cut, sewn, and the seams are sealed with tape so water cannot enter through the needle holes.

Weave the face fabric

Nylon or polyester yarn is woven into a tough, tightly packed cloth. The weave is the first barrier water meets, and it supports the membrane behind it.

Goes in
Nylon Polyester
Laminate the membrane

A thin plastic film with microscopic pores, or a polyurethane coating, is bonded to the back of the fabric. The pores let vapor pass but are far too small for liquid droplets.

Goes in
PTFE Polyurethane Adhesive
Spray the outer repellent

A durable water-repellent finish is applied to the outer face so rain beads up and falls off instead of soaking in. Without it the face fabric wets out and the coat stops breathing.
Cut the panels

Cutters cut the body, sleeve, hood and pocket pieces from the coated roll, taking care not to scratch the membrane.
Sew the seams

Panels are stitched together, and the needle holes along the seams become tiny leak paths. Zips and drawcords are added at the front and hood.

Goes in
Sewing thread Zipper
Tape every seam

A strip of thermoplastic tape is melted over each seam on the inside with heat and pressure. Gore-Tex garments are made only in certified factories, using the tape that Gore specifies.

Goes in
Adhesive
Test and pack

Factories test sample seams in water at intervals during production. Finished coats are then checked for loose threads, folded and packed.

End of the lineRaincoat

Worth repeating

Waterproof fabric is rated in millimeters of water that can stand on it before any seeps through. Mid-range fabric typically has a rating of 5,000.
Garments made from fabrics that exceed 20,000 mm have still leaked through zips, hoods and seams in rain-room testing.