Most swimwear fails not because of poor construction but because of poor fabric selection. The seams hold. The elastic holds. The fabric itself goes thin, loses its colour, or develops a shine that was not there when you bought it. Understanding a few basic things about how swimwear textiles are made can help you buy better and keep what you buy for longer.
Why polyamide is the standard ¶
Polyamide (often sold under the trade name nylon) has been the dominant swimwear fibre since the 1960s because it combines stretch recovery with resistance to chlorine and saltwater. A good swimwear fabric is typically 78-80% polyamide and 20-22% elastane. The elastane provides the stretch; the polyamide provides the recovery and the durability. Fabrics with a higher elastane content feel softer initially but tend to lose their shape faster.
What fabric weight tells you ¶
Swimwear fabric is measured in grams per square metre (GSM). Most mass-market swimwear uses fabric in the 180-210 GSM range. Fabrics in the 220-240 GSM range are heavier, hold their shape better under tension, and resist the thinning that happens with repeated chlorine exposure. The Kiryu mill we work with produces a 228 GSM polyamide that we have been using since the second collection. It is not the cheapest option. It is the right one.
Matte versus shiny finishes ¶
The finish of a swimwear fabric affects both its appearance and its longevity. Shiny finishes are produced by a calendering process that compresses the surface of the fabric. This looks striking when new but tends to break down with UV exposure, leaving the fabric with an uneven sheen. Matte finishes are more stable and hold their colour more consistently over time. Several clients have specifically requested matte fabric after being disappointed by shiny swimwear in photographs.
How to care for swimwear fabric ¶
Rinse in cold fresh water immediately after saltwater or chlorine exposure. Hand wash with a mild detergent, never machine wash. Dry flat in shade, never in direct sun and never in a dryer. The elastane fibres in swimwear fabric are degraded by heat, which is why tumble-dried swimwear loses its shape so quickly. These are not complicated instructions, but they make a significant difference to how long a piece lasts.
The pieces in the Pulse Mind Wave Tech summer collection use fabric from the Kiryu mill and are designed to be worn for several seasons, not one. The care card included with every order covers these points in detail.