Permatex Ultra Copper RTV Silicone Gasket Maker 3 oz Tubes (2-Pack) — High-Temp, Oil-Resistant Sealant

Permatex 81878 Ultra Copper RTV Silicone Gasket Maker is a high-temperature, copper-colored silicone sealant in a 3 oz tube sold as a convenient 2-pack for creating dependable, oil- and coolant-resistant gaskets and repairs.

This two-tube package of Permatex Ultra Copper RTV is formulated to form flexible, durable gaskets where metal-to-metal seals are required and where high heat and exposure to oils or antifreeze are expected. It cures to a firm, copper-colored silicone that withstands engine temperatures and provides a reliable sealing surface without the hassle of premade gaskets. Use it for new gasket fabrication, maintenance repairs, or as a replacement where custom-fit sealing is needed.

How does this product perform under high heat and chemical exposure?

The Ultra Copper RTV is engineered for high-temperature environments and resists degradation from oil, coolant, and common automotive fluids. It remains flexible after curing, tolerating thermal cycling without cracking or shrinking, which helps maintain a long-lasting seal under repeated engine heat-up and cool-down cycles.

• Rated for elevated temperatures common in engine bays
• Resistant to oil, water, coolant and many automotive chemicals
• Thermally stable and flexible after full cure

How do I apply the 3 oz Ultra Copper RTV correctly?

Surface prep is critical: clean and dry mating surfaces, remove old gasket material, and ensure no oil or debris remains. Apply a continuous bead from the 3 oz tube, assemble parts within the recommended skin time, and allow proper cure time before exposing to fluids or full operating temperatures.

• Clean surfaces thoroughly with solvent and scrape old gasket
• Apply bead size appropriate to flange design from the 3 oz tube
• Assemble within skin time and follow Permatex cure recommendations

Will Ultra Copper RTV work for both stationary and dynamic sealing applications?

Yes — it is suitable for both static flange seals and certain dynamic applications where slight movement occurs, because cured silicone stays resilient and resists extrusion. For heavy dynamic sealing or extremely tight tolerance moving parts, check application guidelines to confirm compatibility.

• Ideal for static flanges like valve covers, oil pans, water pumps
• Acceptable for light dynamic joints with minimal movement
• Not intended for high-pressure rotating seals without verification

What are the packaging and sizing details I should know?

This listing contains two 3 oz tubes of Permatex Ultra Copper RTV (Permatex 81878), making it convenient for tackling multiple repairs or keeping a spare tube on hand. The compact 3 oz tubes fit easily in toolboxes and allow controlled bead application for precision projects.

• Two 3 oz tubes included (2-pack)
• Compact tubes for accurate bead control
• Copper-colored silicone for visible, professional-looking seals

Who is this for: Permatex 81878 Ultra Copper RTV in a 2-pack is aimed at DIY mechanics, professional technicians, and restoration enthusiasts who need a reliable, high-temperature silicone gasket maker for engines and mechanical assemblies. It’s ideal when custom-fit sealing is required, for maintenance jobs, or when keeping a spare tube ready for emergencies. If you need a copper-colored, oil- and coolant-resistant sealant that cures to a flexible gasket, this product is designed to meet those needs.