Carbon fiber cloth is prized in aerospace, automotive, and sporting goods for its unbeatable strength-to-weight ratio. Yet that same feather-light weave can quietly degrade if it sits in moist air. Below are the four most common—and costly—consequences, plus quick storage tips to keep your rolls ready for production.
1. Weakened Resin Bond
Most carbon cloth is pre-impregnated with an epoxy or thermoset resin. Moisture migrates along the fiber bundles and attacks the resin’s cross-linked network. The result? A measurable drop in interlaminar shear strength and a greater chance of delamination during lay-up or cure.
2. Swelling & Dimensional Shift
Dry carbon tow is stable, but absorbed water makes individual filaments expand. On a macro scale, the fabric can grow by tenths of a millimeter—enough to throw off precise ply orientations in aerospace skins or thin-walled bike frames.
3. Mold & Surface Contamination
Humid storage rooms are a playground for mildew and mold spores. Once colonies take hold, they discolor the cloth and leave behind acidic by-products that further degrade the resin. A musty roll is often rejected outright by quality control.
4. Corrosive Attack in Extreme Cases
While carbon itself is corrosion-resistant, the sizing or coupling agents on the fiber can react with acidic or alkaline moisture, slowly pitting the surface. Over time, this micro-roughening reduces fiber-to-resin adhesion and lowers fatigue life.
Smart Storage Checklist
• Keep rolls in a climate-controlled area below 50 % RH.
• Use sealed foil or heavy-gauge poly bags with desiccant packs.
• Store off the floor on racks, away from direct sunlight and heat sources.
• Log temperature and humidity daily—small changes today prevent expensive scrap tomorrow.
