Copper Flat Washer Sealing Gasket Assortment Kit – M4 to M14

Copper Flat Washer & Sealing Gasket Assortment Kit

Keep your projects leak-free and fasteners secure with this versatile Copper Flat Washer Sealing Gasket Kit. Available in sets of 50, 100, or 120 pieces, this assortment covers the most common metric sizes (M4 through M14), making it the only kit you'll need for household repairs, automotive work, hydraulic systems, and more.

Why Choose Copper Washers?

Red copper is prized for its outstanding sealing capability, excellent heat resistance, superior electrical and thermal conductivity, and impressive wear resistance. These solid flat gaskets create a reliable, pressure-distributing barrier between fasteners and mating surfaces — reducing friction, preventing loosening, and isolating metal-to-metal contact.

Key Features

• Premium Red Copper Material: High hardness with strong, durable construction for long-lasting performance.
• Multi-Size Assortment: Includes M4, M5, M6, M8, M10, M12, and M14 flat washers in one convenient kit.
• Superior Sealing: Creates a tight, leak-resistant seal for hydraulic fittings, fuel lines, plumbing, and electrical connections.
• Wide Compatibility: Pairs perfectly with standard screws, nuts, and bolts of corresponding sizes.
• Broad Application: Ideal for automotive, marine, industrial machinery, household appliances, and commercial equipment.
• Compact Packaging: Neatly packaged in a 13 × 7 × 2 cm case for easy storage and access.

Size Breakdown by Kit

50-Piece Kit

• M4 × 8 × 1 mm — 10 pcs
• M5 × 9 × 1 mm — 10 pcs
• M6 × 10 × 1 mm — 10 pcs
• M8 × 12 × 1 mm — 5 pcs
• M10 × 14 × 1 mm — 5 pcs
• M12 × 16 × 1 mm — 5 pcs
• M14 × 18 × 1 mm — 5 pcs

100-Piece Kit

• M4 × 8 × 1 mm — 20 pcs
• M5 × 9 × 1 mm — 20 pcs
• M6 × 10 × 1 mm — 20 pcs
• M8 × 12 × 1 mm — 10 pcs
• M10 × 14 × 1 mm — 10 pcs
• M12 × 16 × 1 mm — 10 pcs
• M14 × 18 × 1 mm — 10 pcs

120-Piece Kit

• M4 × 8 × 1 mm — 30 pcs
• M5 × 9 × 1 mm — 30 pcs
• M6 × 10 × 1 mm — 20 pcs
• M8 × 12 × 1 mm — 10 pcs
• M10 × 14 × 1 mm — 10 pcs
• M12 × 16 × 1 mm — 10 pcs
• M14 × 18 × 1 mm — 10 pcs

Specifications

• Material: Solid Red Copper
• Available Quantities: 50, 100, or 120 pieces
• Sizes Included: M4, M5, M6, M8, M10, M12, M14
• Thickness: 1 mm
• Package Dimensions: 13 × 7 × 2 cm
• Made in: Mainland China

Applications

These copper sealing washers are widely used across many industries and DIY applications, including:

• Automotive fuel and oil system fittings
• Marine and hydraulic equipment connections
• Plumbing and pipe fittings
• Electrical appliances and panel assemblies
• Industrial machinery maintenance
• General household repairs and DIY projects

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For more information on safe use of hardware fasteners and tools in industrial and home settings, visit the OSHA Hand & Power Tools Safety Resource.

Note: Monitor brightness and lighting conditions may cause slight color variations compared to actual product. Please allow a minor tolerance in manual measurements.

Frequently Asked Questions

Q: What sizes of copper washers are included in the assortment kit?

A: The kit includes seven metric sizes — M4, M5, M6, M8, M10, M12, and M14 — all at 1 mm thickness. Each size is grouped for easy identification. Depending on the kit size you choose (50, 100, or 120 pieces), the quantity per size varies accordingly.

Q: What are copper flat washers typically used for?

A: Copper flat washers are commonly used in automotive fuel and oil line fittings, hydraulic system connections, plumbing joints, marine equipment, and electrical assemblies. Their excellent thermal and electrical conductivity, combined with strong sealing properties, make them a go-to choice for creating leak-resistant connections in demanding environments.

Q: Are these washers compatible with standard screws and bolts?

A: Yes! These copper gaskets are fully compatible with standard metric screws, nuts, and bolts of the corresponding size (M4 through M14). They provide a wider bearing surface that helps distribute load, reduce friction, and prevent fastener loosening over time.

Q: Why use copper washers instead of steel or rubber ones?

A: Copper offers a unique combination of benefits: superior heat resistance, excellent electrical and thermal conductivity, strong sealing under compression, and good wear resistance. This makes copper washers especially suitable for high-temperature or electrically sensitive applications where rubber or steel may not perform as well.