How do I clean dirty and sticky boat fenders?
My white PVC fenders have turned into a sticky, black mess covered in exhaust soot and harbour grime. I've tried washing-up liquid, but it barely touches the dirt. What is the best way to get them looking new again without degrading the plastic?
Answer
To clean heavily soiled boat fenders, wipe them down with a dedicated marine fender cleaner or a rag soaked in acetone to cut through sticky UV-degraded plastic and exhaust soot. Once clean, you must immediately apply a marine polish or vinyl protector to seal the surface, otherwise they will attract dirt faster than before.
Initial wash and degrease
Before using harsh chemicals, remove loose surface grime, algae and salt. Set up a washing station on the pontoon or boatyard hardstanding. Fill a bucket with warm water and a heavy-duty marine degreaser, such as Star brite Hull Cleaner or a citrus-based bilge cleaner. Give the fenders a vigorous scrub with a stiff nylon brush. This step will not shift black scuff marks or the sticky residue caused by degrading PVC. It does prevent you from wasting expensive solvents on everyday dirt. Rinse them thoroughly with fresh water and let them dry completely.
Tackling sticky PVC and scuffs
When PVC fenders sit in the sun for years, the plasticisers migrate to the surface. This makes them feel tacky and acts like a magnet for diesel soot and creosote from wooden marina pilings. You need a solvent to cut through the degraded layer. Acetone is highly flammable. Work outside and keep it away from naked flames.
- Acetone: This is the boatyard favourite for restoring white fenders. Wear nitrile gloves, pour a splash of acetone onto a white cotton rag, and wipe swiftly. It melts a microscopic layer of the PVC to remove scuffs and stickiness. Do not soak the fender or scrub aggressively, as you will warp the plastic. A 1-litre tin costs about £10 and cleans a dozen fenders.
- Dedicated Fender Cleaners: Products like August Race Fender Mate or Polyform Fender Cleaner are highly effective and less aggressive than pure acetone. They cost between £15 and £20 a bottle and are formulated specifically for marine PVC.
- Magic Erasers: Melamine foam sponges work exceptionally well on minor scuffs when used with warm soapy water. They act as a micro-abrasive and will dull a glossy fender if overused.
Sealing and protecting the surface
Strong solvents like acetone strip the fender of its natural oils. This leaves a matte, porous finish that turns black again within a month if left untreated. You must seal the plastic. Apply a coat of high-quality marine wax, such as Collinite 885 Fleetwax or 3M Marine Restorer & Wax. Alternatively, use a UV spray like 303 Aerospace Protectant. Rub it in firmly with a microfibre cloth, let it haze over, and buff it off. This restores the glossy slip, blocks UV rays, and stops the fender squeaking against your gelcoat in a swell.