Q: When should I use a metal zipper instead of nylon?
Metal is the right call when the zipper is part of the product's visual language or when the opening must survive heavy, repeated side load. Denim flies, leather goods, premium bags, workwear and heritage outerwear all benefit from brass, antique brass or zinc alloy teeth. Metal also tolerates higher pull force, so a #5 metal chain often outperforms a #7 coil at a similar width.
The trade-offs are real. Metal is heavier, stiffer and less forgiving on curved seams, and the plating can corrode or wear through in chlorine, salt or aggressive detergent. Teeth can also abrade lightweight lining fabric if the chain is left exposed during washing. Aluminum is light and corrosion resistant but softer; brass is durable and takes a deep finish; zinc alloy offers cost-effective detail.
Specify the base metal, plating and nickel release compliance, not just the color name, because two visually identical antique finishes can behave very differently after twenty washes. If the garment is garment-dyed or stone-washed, confirm that the finish survives the process before bulk production.