EXTREMEHEAT PASTE - 3 OZ
EXTREMEHEAT PASTE - 3 OZ
EXTREMEHEAT PASTE - 3 OZ
EXTREMEHEAT PASTE - 3 OZ
EXTREMEHEAT PASTE - 3 OZ
SKU: 37901

EXTREMEHEAT PASTE - 3 OZ

$11.99

Attributes

High Temperature

Use On

Automotive
Metal
Concrete
Aluminum
Ceramic

Product Details

J-B Weld ExtremeHeat Paste is formulated to allow for repairs to iron, steel and metal in high temperature environments (1000°F / 538°C). When fully cured, this metallic compound can be drilled, machined or sanded. It is great for repairing cracks, small gaps, seam connections or holes in exhaust manifolds, pipe connections, mufflers, catalytic converters, outdoor grills, fire boxes, gas and commercial furnaces and water heaters. This product is water based, non-flammable and contains no solvents or Volatile Organic Compounds (VOCs).

Get the Safety Data Sheet
For California residents only, check here for warning

Product Attributes

Set Time
1 Hour
Cure Time
24 Hours
Dry Color
Dark Gray

Surfaces

Automotive
Metal
Concrete
Aluminum
Ceramic

How to Use

Prepare

Remove dirt, debris or loose contaminants from surface. Use sand paper to roughen. For some repairs, open small cracks further with a drill or screwdriver to create a 1/8" gap.

Mix

Open J-B Weld® Extreme Heat™. Thoroughly mix product.

Apply

Use product generously, working onto surface or into hole, crack, pit or seam. Repeat as needed. Allow 2-4 hours set up, depending on temperature and current environment.

Dry

Test cure by pressing fingernail or thumbnail into repair material. If unable to penetrate, then repair is complete. If area appears slightly soft, use a non-flame heat source, such as a hair dryer, to speed cure time, or allow 24 hours before allowing high heat exposure. Repeat test until fully cured.

Frequently Asked Questions

What is the maximum temperature ExtremeHeat Paste can handle?

ExtremeHeat is rated to 1000 F / 537 C, and J-B Weld support describes that figure as intermittent exposure rather than a constant operating temperature. Older packaging listed 2400 F; after further testing J-B Weld revised the number down to 1000 F, so use the lower figure. Keep the repair out of direct flame contact, which will burn it regardless of the rating.

Is ExtremeHeat Paste an adhesive or a filler?

It is a filler, not a structural adhesive. ExtremeHeat is made to fill cracks, pits, small gaps and seams in cast iron and steel exhaust parts, not to bond two pieces together or carry a load. For broken brackets, grill legs, grate welds, muffler mounting or anything that must hold weight or resist vibration, have the part welded instead.

Will ExtremeHeat survive contact with water, oil, coolant or fuel?

No. ExtremeHeat is water based, so water, coolant, oil and fuel will soften and eventually dissolve the cured material. If the repair can get wet from rain, road spray or condensation, seal it with a couple of light coats of high-temperature spray paint. For repairs that sit in coolant, oil or fuel, use Original J-B Weld (8265S) instead.

Can I use ExtremeHeat to repair a cracked cast iron wood stove or firebox?

Yes, on cast iron, for sealing cracks and seams that are not in direct flame contact. It also works for sealing the gap where the stove pipe enters the collar. It is less reliable on sheet steel stove bodies. Because it is water based, keep water off it during and after curing, and do not light the stove until the repair has fully cured.

Is ExtremeHeat safe for grills, smokers, ovens or anything that touches food?

ExtremeHeat is non-toxic once cured, but it has not been tested or rated as food safe, so J-B Weld does not recommend it where it can contact food. That rules out oven floors, cooking pots, baking pans and grill cooking surfaces. Repairs to handles, legs and other parts away from food are different, but grease and cleaning water will still dissolve it.

How long does ExtremeHeat take to set and cure, and can I speed it up?

Allow 2 to 4 hours to set up and 24 hours for full cure before any high-heat exposure. Test it by pressing a fingernail into the repair; if you cannot dent it, it is cured. A non-flame heat source such as a hair dryer will speed the cure. Working time is roughly 15 minutes, and a few drops of water will extend it.

Reviews