Copper Sealing Washers 330 Pcs Kit

This kit delivers 330 flat copper washers in 12 standard metric sizes: M5, M6, M8, M10, M12, M14, M16 and M20. Sizes are grouped logically — smaller diameters (M5–M10) dominate the count for high-frequency applications like oil filters and brake bleeder valves, while larger sizes (M12–M20) cater to heavy-duty uses including axle flanges, transmission fill plugs and industrial pump couplings. All washers are made from oxygen-free copper (OF-Cu), offering maximum ductility and minimal impurity content — critical for achieving full crush without fragmentation. Thickness is uniformly 1.5 mm; outer diameters scale proportionally — e.g., M12: ~22 mm OD, M16: ~28 mm OD — matching original equipment specifications across major European vehicle platforms. Their primary function is to create static, pressure-retentive seals at threaded interfaces subject to thermal cycling, vibration and fluid exposure. When compressed, copper flows laterally to fill surface imperfections, forming a continuous barrier against oil, diesel, coolant and hydraulic fluid. This mechanism is especially effective where dynamic sealing (e.g., O-rings) is impractical — such as on hot exhaust-mounted sensors or submerged gearbox breathers. Used extensively by MOT-certified garages, rail maintenance depots and municipal fleet workshops across the UK and Ireland. Also specified for marine diesel engine servicing (ISO 8504 compliant), agricultural tractor PTO shafts and compressed air distribution systems. The storage box features anti-static properties to prevent dust adhesion, and includes a removable internal tray for easy refilling or partial kit transfers to portable tool rolls.