Navigating These Challenging Times Together

First, we want to thank you again for your continued support during this difficult time. Like everyone else we are just trying to take things one day at a time and get through this the best we can. We'd like to share some information with you to help you stay updated with what's going on at Hatchet Hardware in the coming days.

Store Hours:
As an essential business, our shops will continue to stay open. Our teams are working incredibly hard to be here for our communities in any way that we can so please be courteous. You can find our current store hours on the locations page:
Feel free to call the shops ahead to make sure we have whatever you need before coming out and please remember that you can shop online at at any time.

Steps We're Taking:
Our offices are all currently set up to work from home to help stop the spread of COVID-19. At our warehouse and shops, we have increased efforts to disinfect high-touch and high-trafficked areas throughout the day and increased daily cleaning routines. We are also making sure all employees have up-to-date information on how to stay healthy and what preventative measures should be taken and the ability to stay home if they are feeling unwell.

You may experience delays in shipping as we are taking the necessary precautions to protect you and our team. We are still working hard to get in-stock items shipped within 24 hours. Few items may temporarily have longer fulfillment times.

Customer Service:
Our customer service team is working hard to help all customers as quickly as possible. Due to technical difficulties and a higher volume of calls you may experience interruptions. In the event this occurs, please email us at or message our chat here on the site. We apologize for any inconvenience and thank for your continued support and understanding.

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Permatex 81878 Ultra Copper High Temp RTV Silicone Gasket Maker, 3 Oz

Regular price $8.59

Free Shipping over $35

Available for store pickup from Brunswick. 3 in stock.
Available for store pickup from Troy. 2 in stock.
Available for store pickup from Waterford. 2 in stock.
Available for store pickup from Niskayuna. 3 in stock.
Available for store pickup from Palatine. 3 in stock.
This item is not available for local pickup.
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Permatex gasket makers offer significant performance advantages which include outstanding oil resistance, excellent torque retention and hi-temp, sensor-safe properties. Extended warranties, 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.

The most advanced, high temp RTV silicone gasket available. Sensor-safe, low odor, noncorrosive. Superior adhesion. Three times more oil resistant than conventional silicones; eight times more flexible than cut gaskets. Temperature range -65°F to 700°F (-54°C to 371°C) intermittent; resists auto and shop fluids and vibration.

Permatex Ultra Copper is a single component, room temperature vulcanizing gasketing compound designed to provide reliable “formed-in-place” gaskets for mechanical assemblies. This material cures on exposure to moisture in the air to form a tough, flexible, silicone rubber gasket. The product resists aging, weathering and thermal cycling without hardening, shrinking or cracking. Designed for the higher temperature environments encountered in 4-cylinder, turbocharged, and high performance engines. Permatex Ultra Copper is the most advanced high performance, high temperature (up to 700°F intermittent) RTV gasket available. OEM Specified.


  • Sensor-safe
  • Oil and gas resistant
  • Designed and recommended for post-1980 4-cylinder, turbocharged or high performance engines
  • Low odor, non-corrosive
  • Superior adhesion and flexibility
  • Can be used as a gasket maker or dressing
  • Non-flammable, Non-toxic
  • More oil resistant than conventional silicones; more flexible than cut gaskets
  • -75 to 700 degrees Fahrenheit intermittent temperature range
  • Resists auto and shop fluids and vibration
  • Carded


  • For Automotive: Exhaust manifolds/headers, valve covers, oil pans, timing covers, water pumps, thermostat housings
  • For Motorcycle: Exhaust header flanges, slip fit exhaust pipes, and muffler end caps
  • For Marine: Exhaust manifolds/headers, valve covers, oil pans, intake manifold end seals, water pumps, exhaust tubes


  • Chemical Type: Oxime silicone rubber
  • Appearance: Copper colored non-sag paste
  • Flash Point °C (°F): >93 (>200)
  • Size: 3 Oz
  • Type: High Temperature
  • Packing Type: Tube
  • V O C Content: 3 %
  • Odor Scent: Low odor
  • Form: Paste
  • Drying Time: 24 hr
  • Applicable Materials: Aluminum, Brass, Iron
  • Application Time: 2 hr
  • Standards: OEM Specified
  • Odor Scent: Mild
  • Flammability Rating: 1
  • Composition: RTV silicone, poly hydroxy, modified silicon dioxide
  • Specific Gravity: 1.05
  • Extrusion rate @ 25°C, (grams/min): >300

Typical Curing Performance:

Permatex Ultra Copper Hi-Temp RTV Silicone Gasket cures on exposure to moisture in the air. The product dries tack free in one hour and fully cures in 24 hours. Cure times will vary with temperature, humidity and gap.

Chemical / Solvent Resistance:

The product retains effective properties in contact with automotive fluids, such as motor oil, transmission fluids, alcohol and antifreeze solutions. Note: Not recommended for parts in contact with gasoline.

General Information:

This product is not recommended for use in pure oxygen and/or oxygen rich systems and should not be selected as a sealant for chlorine or other strong oxidizing materials.



2.0 lb


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