J-B Weld Hi-Temp Silicone Gasket Maker & Sealant Red 85g

J-B Weld Hi-Temp Silicone Gasket Maker & Sealant Red 85g is a high-temperature RTV silicone gasket maker and sealant designed for mechanical and automotive assemblies exposed to demanding temperatures. It provides temperature resistance up to 287°C (550°F) continuously and 343°C (650°F) intermittently, making it ideal for high-heat sealing and gasket-making applications.

The RTV (Room Temperature Vulcanizing) silicone cures when exposed to moisture in the air, forming a tough, flexible and waterproof seal on most suitable surfaces. It can be used where a durable gasket or seal is required around components exposed to heat, moisture, weathering and normal mechanical operating conditions.

J-B Weld Hi-Temp Silicone is particularly well suited to automotive repair and maintenance applications. Its ability to withstand elevated temperatures makes it useful for suitable engine and mechanical assemblies where standard silicone sealants may not provide sufficient heat resistance.

Once cured, the red silicone forms a durable seal that will not shrink or crack. It also offers excellent resistance to weathering, helping maintain the integrity of the seal over time.

The formulation is sensor safe, making it suitable for compatible automotive applications where this characteristic is required.

For anyone looking for a high-temperature RTV silicone, red gasket maker, automotive gasket sealant or heat-resistant silicone capable of handling temperatures up to 343°C intermittently, J-B Weld Hi-Temp Silicone Gasket Maker provides a specialist solution for demanding sealing applications.

Key Benefits

• High-temperature RTV silicone gasket maker

• Suitable for gasket-making and sealing applications

• Designed for mechanical assemblies

• Ideal for many automotive applications

• Withstands continuous temperatures up to 287°C / 550°F

• Withstands intermittent temperatures up to 343°C / 650°F

• RTV – Room Temperature Vulcanizing silicone

• Moisture-curing formulation

• Creates a tough seal after curing

• Forms a waterproof seal

• Suitable for most compatible surfaces

• Will not shrink after curing

• Designed not to crack

• Resistant to weathering

• Sensor-safe formulation

• Flexible silicone seal

• Ideal for demanding high-heat applications

• Red colour for easy identification

• Convenient 85g tube

How to Use

• Ensure the mechanical assembly and surfaces are cool before application.

• Remove old gasket material, sealant, oil, grease, dirt and other contaminants from the surfaces being sealed.

• Make sure the surfaces are suitably prepared before applying the silicone.

• Apply J-B Weld Hi-Temp Silicone in a continuous bead to the required gasket or sealing area.

• Ensure the bead is positioned correctly around the mating surface and any required openings.

• Assemble the components according to the equipment manufacturer's instructions.

• Remove excess uncured sealant where necessary.

• Allow the RTV silicone to cure according to the manufacturer's instructions before placing the assembly into normal service.

• Do not expose the repair to operating temperatures until the silicone has cured as directed.

• Always follow the product instructions and the mechanical or vehicle manufacturer's requirements for the specific gasket application.

Typical Applications

• Automotive repairs

• Mechanical assemblies

• High-temperature gasket making

• Replacement formed-in-place gaskets

• Engine-related sealing applications

• High-heat mechanical components

• Automotive maintenance

• Workshop repairs

• Waterproof mechanical sealing

• Applications requiring sensor-safe RTV silicone

Product Information

Brand: J-B Weld
Product: Hi-Temp Silicone Gasket Maker & Sealant
Size: 85g
Colour: Red
Type: RTV Silicone Gasket Maker & Sealant
RTV: Room Temperature Vulcanizing
Continuous Temperature Resistance: Up to 287°C / 550°F
Intermittent Temperature Resistance: Up to 343°C / 650°F
Waterproof When Cured: Yes
Sensor Safe: Yes
Shrink Resistant: Yes
Crack Resistant: Yes
Weather Resistant: Yes
Curing Method: Exposure to moisture in the air
Primary Use: High-temperature automotive and mechanical gasket making & sealing

WEEE Recycling Producer Registration Number:12889

How do I return my old product to be recycled?

You can return your old product to MyDIY. Waste Electrical and Electronic Equipment (WEEE) is taken back free of charge on a one-for-one, like-for-like basis. Waste batteries including rechargeable batteries are taken back free of charge. You are not obliged to make any purchase when returning old batteries. Each local authority must also accept household WEEE and small batteries free of charge at its recycling facilities. All WEEE and waste batteries must be recycled and should not be placed in any of your household wheelie bins. Make sure you always recycle all your old electrical goods and batteries.

What products can I recycle for free?

You can return anything that is electricaly powered or battery powered. Even your old bicycle lamps can be recycled!.

Do you take back used batteries?

Yes we do. The batteries that we accept are AA, AAA, C or D, powertool batterys and also the flat batteries that are found in watches and toys. Unfortunately we do not accept back any Industrial or car batteries.

Do I need to have made a purchase at MyDIY.ie?

No you don't. You can recycle any of the above items at our store in Inchicore Dublin 8, even if you have not made a purchase with us.

Will you collect my old product?

Yes, but we must be notafied within 14 days of purchase date. You can still arrange to have your old appliance recycled free of charge. Simply bring it back to our Inchicore store and we will ensure that it is disposed of in an environmentally friendly manner.

How much will it cost?

There is no charge to return products to any of our warehouses.

Why should I recycle with MyDIY?

We will ensure that your old product is disposed of correctly to reduce the potentially harmful effects caused on the environment and to conserve natural resources. Further information can be found on weeeireland.ie.

EMC (Environmental Management Cost) Included in the purchase price. 

Gas discharge lamps, LFLs and CFLs €0.15

LED lamps and luminaires €0.05

Large appliances €5.00

Information

Fast & Reliable Shipping with DPD

We ship all orders via DPD, one of Ireland’s most trusted couriers. With DPD’s one-hour delivery window, you won’t have to wait around all day for your MyDIY.ie order!

Delivery Times

Each product on our website is marked with an estimated delivery time. If you order multiple items, your order will arrive based on the item with the longest delivery time. For example, if you buy two next-day items and one 3-day item, the entire order will arrive in 3 days.

While most products arrive in 1-2 days, we offer over 44,000 items, so please allow 4-5 working days for some deliveries. Need it faster? Call us at 01-446692, and we'll do our best to help.

Delivery Charges

• FREE delivery for orders over €150 within Ireland.

• Orders under €150: €8.99 delivery fee.

• International delivery: Charges based on weight—contact us for a quote.

When Will I Receive My Order?

• Most orders ship on a 24-hour courier service (2 working days).

• Larger orders may take 4-5 days, and pallet deliveries require scheduling.

• Orders placed before 2 PM usually ship within 24 hours.

• Orders after 1:30 PM Friday or on weekends ship the following week.

• Busy holiday periods may cause slight delays beyond our control.

Do I Need to Be Home for Delivery?

Yes, someone must sign for deliveries due to item value. If you're not home, DPD will leave a card with re-delivery or collection instructions. After two failed attempts, your order may be returned to us, and a re-delivery fee may apply.

Damaged or Incomplete Orders

We carefully pack all orders, but if something arrives damaged or incomplete, contact us within 24 hours. Report shortages within 3 days of delivery.

International Shipping

We ship to Europe and worldwide, with charges based on weight. Liquid products cannot be shipped internationally due to regulations. Contact us for a quote—we're happy to help!

Customer Service & Returns

• Great product and quick delivery, very good staff

  5/5

  Written by: Mr Diver

  Date: 28/08/2026