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🔥 Fix it once, fix it extreme. The heat-proof bond that means business.
J-B Weld 37901 ExtremeHeat is a 3 oz metallic paste designed for high-temperature repairs up to 1000°F (537°C). It forms a permanent, steel-strong bond without the need for torch welding, cures fully in 24 hours, and can be drilled or sanded after curing. Ideal for repairing iron, steel, and alloy components in extreme heat environments such as exhaust manifolds, grills, and furnaces, it is non-flammable, solvent-free, and waterproof, making it a reliable and eco-conscious choice for professional-grade fixes.









| ASIN | B01IBOBY74 |
| Best Sellers Rank | #1,010 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #6 in Industrial Lubricants |
| Brand | J-B Weld |
| Brand Name | J-B Weld |
| Color | Grey |
| Compatible Material | Alloy Steel, Iron |
| Container Type | Tube |
| Customer Reviews | 4.2 out of 5 stars 12,138 Reviews |
| Full Cure Time | 24 Hours |
| Global Trade Identification Number | 00043425379016 |
| Included Components | Metallic Paste Repair Bottle 3 oz. |
| Item Form | Paste |
| Item Package Quantity | 1 |
| Item Type Name | ExtremeHeat High Temperature Resistant Metallic Paste - 3 oz |
| Item Weight | 3.04 ounces |
| Manufacturer | JBWeld |
| Material | Metal, Aluminum |
| Material Type | Metal, Aluminum |
| Model | 37901 |
| Other Special Features of the Product | Heat Resistant |
| Part Number | 37901UK |
| Special Feature | Heat Resistant |
| Specific Uses For Product | ['Repair', 'High Temperature Environments'] |
| UPC | 043425379016 043425700285 |
| Unit Count | 3.0 Ounce |
| Viscosity Level | High |
| Volume | 3 Fluid Ounces |
| Warranty Description | No Warranty |
| Water Resistance Level | Waterproof |
A**E
Great product with long-term results, if you use it correctly!
I purchased this item to repair an ash fettle in an old Vermont Castings wood burning stove, and it completely exceeded my expectations outlasting an entire season of direct fire contact. The fettle was cracked into two pieces and a prior owner had drilled two holes on either side and tried to connect it with an aluminum "bridge." The repair interfered with the door closing, so I needed to seamlessly "weld" the two cast iron sides back together. Before going through the trouble of taking it to a welder and paying to have it repaired properly, I took a chance on this J-B Weld ExtremeHeat. I used a Dremel tool with a fine grinding stone and cleaned up the two broken faces, along with about 1/4 inch of the area on either side of the crack. Following the advice of another review, I then took a cotter pin, stuck it into the chuck of my battery powered drill, and used that to thoroughly stir the J-B Weld in the container (this is a one-time use container... once opened and stirred, use it and toss the rest). After stirring for just under 2 minutes, I immediately applied it to the two surfaces, pieced them together, and then spread a little more on either side to ensure a supported bond. I then set the item on a flat piece of cardboard to cure for 2 days. (NOTE: you have to support the joint while curing, because the J-B Weld provides no structural support until completely cured. While wet, the item will just fall apart again if the pieces aren't otherwise held together.) When it was done, I replaced the fettle and lit the first fire of the season (crossing my fingers at the same time). Several months and probably 100+ fires later, the piece was still holding strong like the day I put it in. The fettle sits right against the fire, and many logs have rolled into it while it was extremely hot, with no noticeable damage whatsoever. I would absolutely recommend and use the J-B Weld ExtremeHeat again on future projects. As long as the proper preparation is done, and you follow the instructions, it's an awesome product!
M**V
Fixed exhaust leak
Worked well for sealing my exhaust fittings. Easy to apply since its a bit thick, use it all in one go cause it isn't usable afterwards.
J**N
Handy heat resistant paste for fixes
Yes, this stuff is way better than the random glues i kept grabbing at the hardware store. I got it for my dorm because my old car’s exhaust had a tiny crack and I can’t afford a shop visit right now. Mixed it, spread it on with a plastic knife, and let it cure a full day before driving. No more rattling sound or weird fumes. That alone made me really glad i bought it. I also used a bit on a busted metal fan guard and it’s holding reallly tight so far. Smells strong, so do it outside.
K**.
Litterally Saved Me Hundreds of Dollars
I purchased this as a desperate attempt at saving my 26 year old cub cadet tractor. It is a one year only engine and developed a crack in the heat that was allowing oil to spray out. A new head used on ebay runs $200-300 and to have a shop correctly weld it is a similar price. I wire brushed the crack and used this jb weld. Let it set for 24 hours and it was solid as a rock. I have mowed about 4 times since and no signs of a leak. Will keep my old mower running for a few more years.
K**D
Effective adhesive for repair work
Probably saved me a lot of money on a repair job at home. I used this J-B Weld Extreme Heat to fix a crack in my cast iron skillet. It bonded well and restored the smooth surface. I'm glad I gave it a try.
G**S
Better than the squeeze tube of J-B Weld muffler repair but still limited capabilities.
I followed the instructions on this product well and while it did perform better than the squeeze bottle J-B Weld high temperature muffler repair, this product still cracked under frequent hot-cold cycles on an exhaust system. It did last longer than the dedicated muffler repair product which is why it's getting at least the 3 stars.
R**W
does not work well
Bought this due to the high temp claim. tried it on my small 24 hp kohler exhaust pipe that 90's angles into the muffler, sealing around the pipes. Firstly it completely separates sitting in the jar for more than a day. Once stirred up it turns to the gray color of standard jb weld but the consistency is more watery and drops instead of staying in place. i allowed more than 24 hours ( 1 week) to cure before running the mower. After a lawn cutting (about 45 min) I can see half of this jb weld has cracked and fallen off, the rest can be popped off easily by hand and I tried to layer after finding it failed the first time, that didn't make a difference. I will just end up actually welding the joints vs this junk. I was really hoping that this would work since their normal jb weld stuff works well. it also it turns white once a heat cycle has been applied to it, it doesn't stay gray in color.
F**O
Great solution at a great price.
Great J-B Weld solution at a great price.
K**W
bra pris
kanon
R**I
It works.
Amazing result. Used on an old gas oven door. Unable to get parts to repair handle but this product did the trick. Very pleased.
J**A
Very good and handy product for repairing metal cracks..
I bought it to fill the gap developed in high pressure vessel..it is very good and handy in such situations..highly recommend.
T**S
Produit miracle
Reparer un coude d’echapement sur un bateau le temps d’avoir la piece de rechange.
S**I
Amazing
This glued me and my wifes marriage back together
Trustpilot
1 day ago
1 month ago