Drying Methods for Technical Fabrics

Two variables determine whether drying damages a fabric: heat level and drying method (tumble vs. line). Getting either wrong doesn't produce immediate visible damage — it produces cumulative degradation that shortens product life, kills elastic recovery, and in the case of PUL, causes irreversible delamination. Understanding the thresholds across fiber types lets you make the right call for any product in your lineup.

What Dryer Heat Settings Actually Mean

Dryer heat settings are not standardized across manufacturers, but the ranges across major brands converge closely enough to apply general guidance. These are the actual drum temperatures produced at each setting:
The table below applies across standard residential dryers. All figures reflect typical ranges — your dryer may vary. Results may vary based on dryer model, load size, and product construction.

Setting	Fahrenheit	Celsius	Safe for
Air fluff / no heat	65–85°F	18–29°C	All fabrics including PUL and elastics
Low / delicate	95–130°F	35–55°C	All fabrics including PUL and elastics
Medium / permanent press	115–140°F	46–60°C	Cotton and Zorb inserts only — not PUL or elastics
High / regular	135–160°F	57–71°C	Not recommended for any Wazoodle fabric in regular use

Key Concept: 130°F (55°C) is the maximum safe dry heat threshold for PUL fabric. Low heat stays below this ceiling and simultaneously protects elastics, bamboo viscose, and performance finishes. Low heat is the universal safe setting for any multi-component reusable product.

The Weakest-Link Rule for Multi-Component Products

When a finished product combines multiple fabric types — a cloth diaper with a PUL shell, bamboo insert, and elastic channels — the most heat-sensitive component sets the drying temperature for the entire product.

Safe Drying Temperature by Component Type

PUL (all variants): Low heat maximum — 130°F / 55°C. Dry heat above this threshold softens the polyurethane film and permanently damages waterproofing. CORE PUL's three-layer construction provides additional physical protection, but the rated threshold is the same. Do not iron PUL or expose to direct high heat from any source.
Elastics and spandex-content fabrics: Low heat strongly preferred. Repeated medium or high heat cycles progressively degrade elastic recovery — the cause of sagging leg gussets and waistband failure. Let products cool completely before stretching, stuffing, or folding after any heat drying.
Bamboo viscose: Low heat only. Bamboo viscose is a softer, more heat-sensitive fiber than cotton — medium heat causes progressive shrinkage and surface roughening over repeated cycles.
Cotton and Zorb 3D inserts (dried separately from PUL): Medium heat acceptable. When drying cotton prefolds, flats, or Zorb 3D inserts as standalone items without PUL or elastic components, medium heat is safe. High heat causes cumulative fiber weakening over many wash cycles and is not recommended for regular use.
Merino wool: Never tumble dry untreated merino. Heat combined with moisture and agitation causes irreversible felting. Lay flat to dry away from all heat sources. Superwash-treated merino only may be tumble dried on low.
Performance polyester: Low to medium heat. The fiber itself tolerates dryer temperatures well, but topical moisture-wicking finishes degrade faster with heat. Low heat extends the life of wicking performance.

Never dry a stained item on heat until you have confirmed the stain is fully removed in natural light. What appears resolved when wet may still carry residue that heat will permanently set. For stain treatment and air-drying guidance, see CA-02: Stain Removal.

Line Drying: Benefits and UV Caution

Line drying extends product life across every fabric type — no mechanical abrasion, no heat stress, no elastic fatigue. Sun drying also provides natural UV sanitization and stain removal on white and light-colored cotton items. However, UV exposure is not uniformly safe across fabric types.

Line Drying by Fabric Type

PUL fabric: Shade dry only. Direct UV exposure degrades the urethane film — causing yellowing and cracking. At high UV index, film damage can occur in as little as 10 hours of direct sun exposure. Brief sun exposure for stain removal is acceptable, but routine extended sun drying of PUL should be avoided.
Elastics and spandex: Shade preferred. UV progressively degrades elastic recovery in conventional elastane. Hang products by the body of the fabric — not by elastic edges — to avoid gravity-stretching wet elastics.
White cotton inserts and prefolds: Sun drying actively beneficial. UV provides natural bleaching and sanitization. Remove promptly when dry.
Bamboo viscose, colored fabrics: Shade or indirect sun. Extended UV exposure causes fading in dyed fabrics and can affect bamboo's surface texture over time.
Merino wool: Lay flat in shade. Never hang wool to dry — gravity and moisture weight cause stretching and distortion.

Wind stress is not a meaningful risk. Fabric movement during line drying does not cause measurable fiber damage under normal conditions. UV exposure is the primary concern for outdoor drying — manage it by choosing shade for heat-sensitive components.

For detergent and general care rules that affect how you approach drying, see General Care Principles. For drying decisions during stain treatment, see CA-02: Stain Removal.