---
product_id: 1934494
title: "81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube"
brand: "permatex"
price: "2134 kr"
currency: ISK
in_stock: true
reviews_count: 8
category: "Permatex"
url: https://www.desertcart.is/products/1934494-81878-ultra-copper-maximum-temperature-rtv-silicone-gasket-maker-3
store_origin: IS
region: Iceland
---

# Max Temp 700°F 8x Flexibility 3x Oil Resistant 81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube

**Brand:** permatex
**Price:** 2134 kr
**Availability:** ✅ In Stock

## Summary

> 🔥 Seal the deal with the ultimate high-temp gasket maker! 🛠️

## Quick Answers

- **What is this?** 81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube by permatex
- **How much does it cost?** 2134 kr with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.is](https://www.desertcart.is/products/1934494-81878-ultra-copper-maximum-temperature-rtv-silicone-gasket-maker-3)

## Best For

- permatex enthusiasts

## Why This Product

- Trusted permatex brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Sensor-Safe & Low Odor:** Formulated to protect sensitive engine sensors and components with a non-corrosive, low-odor formula—ideal for modern vehicles.
- • **Superior Oil Resistance:** Three times more oil resistant than standard silicones, ensuring long-lasting seals even in the harshest automotive environments.
- • **Unmatched Heat Endurance:** Withstands extreme temps from -75°F to 700°F intermittent—engineered for high-performance engines and turbocharged setups.
- • **Universal Fit & Waterproof:** Designed for universal application on pipes and metal surfaces, providing a waterproof, durable bond that resists shop fluids and vibration.
- • **Flexibility That Outperforms:** Eight times more flexible than traditional cut gaskets, adapting perfectly to vibrations and thermal expansion without cracking.

## Overview

Permatex 81878 Ultra Copper RTV Silicone Gasket Maker is a top-tier, high-temperature sealant designed for professional-grade automotive and industrial use. It offers exceptional oil resistance, extreme flexibility, and sensor-safe adhesion, making it the go-to choice for turbocharged engines and high-performance applications. Its waterproof and low-odor formula ensures reliable, long-lasting seals under the toughest conditions.

## Description

Permatex Ultra Copper Maximum Temperature RTV Silicone Gasket Maker is the most advanced, high temp RTV silicone gasket available. Three times more oil resistant than conventional silicones and eight times more flexible than cut gaskets, it is sensor-safe, low odor, and non-corrosive with superior adhesion. Highest operating temperatures for 4-cylinder, turbocharged or high-performance engines and OEM specified, with a temperature range of -75 degrees fahrenheit to 700 degrees fahrenheit intermittent. Also resists auto and shop fluids and vibration. These gasket makers offer significant performance advantages, excellent torque retention and hi-temp, sensor-safe properties. engine sensors and new component materials such as aluminum, bi-metal alloys and high-tech plastics, have created the need for superior RTV silicone gasket makers in both OEM production and service applications. Permatex always has the right gasket maker for your application.

Review: Worked for furnace ducts - Working well on some ducting coming into and off of my furnace
Review: Great product - Use on exhaust or anyplace else you need a seal for extended high heat use!

## Features

- Most Advanced, High Temp Rtv Silicone Gasket Available.Fit Type: Universal
- Three Times More Oil Resistant Than Conventional Silicones; Eight Times More Flexible Than Cut Gaskets
- Sensor-Safe, Low Odor, And Non-Corrosive With Superior Adhesion
- Temperature Range -75F To 700F Intermittent

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0002UEOPA |
| Best Sellers Rank | #1,740 in Automotive ( See Top 100 in Automotive ) #5 in Gasket Sealers |
| Brand | Permatex |
| Color | Copper |
| Customer Reviews | 4.7 4.7 out of 5 stars (3,164) |
| Date First Available | June 3, 2025 |
| Exterior | Painted |
| Full Cure Time | 24 Hours |
| Global Trade Identification Number | 00686226818782 |
| Is Discontinued By Manufacturer | Yes |
| Item Form | Paste |
| Item Weight | 3 ounces |
| Item model number | 81878 |
| Liquid Volume | 3000 Milliliters |
| Manufacturer | Permatex |
| Manufacturer Part Number | 81878 |
| Material | Metal |
| Model | Permatex 81878 |
| National Stock Number | 8030-01-598-1435 |
| Number of Items | 1 |
| OEM Part Number | PMT81878 |
| Product Dimensions | 8 x 4 x 2 inches |
| Special Features | Forms a superior bond on oil contaminated metals and maintains outstanding oil resistance |
| Surface Recommendation | Pipe |
| UPC | 686226818782 |
| Unit Count | 3.0 Ounce |
| Water Resistance Level | Waterproof |

## Product Details

- **Brand:** Permatex
- **Color:** Copper
- **Full Cure Time:** 24 Hours
- **Item Weight:** 85 Grams
- **Liquid Volume:** 3000 Milliliters

## Images

![81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube - Image 1](https://m.media-amazon.com/images/I/81freAdVPGL.jpg)

## Questions & Answers

**Q: Can this be used on a valve cover gasket to get a better seal?**
A: Yes.  It is better than OEM gaskets in that it conforms to any warpage, dents, dings, & other incongruities, whereas OEM gaskets are designed for factory new, perfect valve covers without flaws.  Withstands 700 degrees.

**Q: Can I use this product to seal several non-moving parts of a wood burning stove instead of the standard gasketing material?**
A: This gasketting goop is absolutely incredible for sealing wood stove parts.  I’d certainly never use it on the fire box.  But it can and will hold to moving parts in high temperatures.  It lasts for several years on one application.

**Q: can I use this to seal radiator tubes to a heat exchanger in my gas furnace? Gaskets no longer available for it.**
A: Greetings! As I don't know this application, specifically, I can say that say that Ultra Copper is excellent for sealing liquid coolant surfaces in truck/auto repairs. Temperature, up to about 800*F and pressures exceeding 15 psi will remain sealed with this product. U.C. remains a pliant sealing silicone "glue", but it won't harden, as epoxy does. If you need a sealer that also hastens, look elsewhere. If this is for a flange or any flat, secured surface, you're good-to-go. NO acetic acid in this product, if that's a plus for you.

**Q: Can I spread this on outside of exhaust manifold leak like you would caulk something or does it have to go between parts?  F150 '04 V8**
A: It is too much pressure and heat to use any caulk or rtv. Even muffler cement doesn't work. You might have a lean fuel mixture to cause the problem in he first place. Exhaust bolts rust solid from heat erosion, use the right amount of points on the socket to get bolts out(6 sided bolt--6 sided socket) Copper metal exhaust gaskets work well. Mr. Gasket brand.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Worked for furnace ducts
*by N***E on December 4, 2025*

Working well on some ducting coming into and off of my furnace

### ⭐⭐⭐⭐⭐ Great product
*by P***D on December 29, 2025*

Use on exhaust or anyplace else you need a seal for extended high heat use!

### ⭐⭐⭐⭐⭐ The Only RTV for High-Heat Engine Jobs
*by M***N on October 11, 2025*

If you're working on anything high-heat, like an exhaust manifold or turbo application, this is the only gasket maker to use. The Ultra Copper RTV is a workhorse—it handles maximum temperatures without breaking down, shrinking, or leaking. It goes on smoothly, cures quickly, and forms a super durable, tight seal. I've used it on headers where standard RTV would just burn up, and this holds strong. It's the professional choice for reliability under extreme heat. Essential for engine work.

## Frequently Bought Together

- Permatex 81878 Ultra Copper Maximum Temperature RTV Silicone Gasket Maker, 3 oz. Tube
- J-B Weld 37901 ExtremeHeat High Temperature Resistant Metallic Paste - 3 oz
- Permatex 80335 Muffler and Tailpipe Sealer, 3 oz., Plastic, 1 Count (Pack of 1)

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*Product available on Desertcart Iceland*
*Store origin: IS*
*Last updated: 2026-01-25*