


🔥 Fix it once, fix it for life — the heat-proof hero your toolbox deserves!
J-B Weld 37901 ExtremeHeat is a high-temperature resistant metallic paste designed for permanent repairs on iron, steel, and metal surfaces exposed to extreme heat up to 1000°F (537°C). Non-flammable and solvent-free, it cures in 24 hours to form a bond stronger than steel, ideal for exhaust systems, grills, furnaces, and more. Its high-viscosity formula is easy to apply and can be drilled or sanded once cured, delivering professional-grade durability without the need for torch welding.









| ASIN | B01IBOBY74 |
| Best Sellers Rank | #1,251 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #10 in Industrial Lubricants |
| Brand | J-B Weld |
| Color | Grey |
| Customer Reviews | 4.2 4.2 out of 5 stars (11,729) |
| Date First Available | July 12, 2016 |
| Full Cure Time | 24 Hours |
| Global Trade Identification Number | 00043425379016 |
| Is Discontinued By Manufacturer | No |
| Item Form | Paste |
| Item Package Quantity | 1 |
| Item Volume | 3 Fluid Ounces |
| Item Weight | 3.04 ounces |
| Item model number | 37901 |
| Manufacturer | JBWeld |
| Manufacturer Part Number | 37901UK |
| Material | Metal, Aluminum |
| Model | ExtremeHeat High Temperature Resistant Metallic Paste - 3 oz |
| Package Information | Tube |
| Product Dimensions | 1.57 x 1.57 x 2.05 inches |
| Special Feature | Heat Resistant |
| Special Features | Heat Resistant |
| Specific Uses For Product | ['Repair', 'High Temperature Environments'] |
| UPC | 043425379016 043425700285 |
| Unit Count | 3.0 Ounce |
| Viscosity | High |
| Viscosity Level | High |
| 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!
X**P
J-B Weld To The Rescue!
J-B Weld to the rescue! My 2004 Nissan Xterra V6 developed a leak at the exhaust manifold side of the pipe connecting the EGR valve to the exhaust manifold. The tell tale sign was smoke (like cigarette smoke) coming from the base of the pipe to the EGR valve and the smell of unburnt fuel. The ideal solution was to replace the pipe but there is no room to get to the hold down nut anchoring the pipe to the manifold. I decided to use J-B Weld 37901 to seal the leak. I had my doubts but after applying three layers of this stuff, one day at a time, there is no sign of the smoke and smell. This was not easy to apply because of the tight space but it worked well using just one finger (mechanic's gloved) tracing around the pipe connector to the manifold. It dries quickly and spreads slowly to keep the form. Time will tell if the fix will hold for at least a year. Check out the pictures.
J**M
Great product!
I used JB weld extreme heat on my outdoor wood boiler. The cast iron door had a nickel sized hole and the steel that the door closes against had deteriorated because of the hole in the door. This stuff worked with minimal effort. The steel and cast iron was cleaned to the bare metal with a wire brush on a drill to insure adhesion. The high heat has not affected the JB weld whatsoever. Highly recommended.
R**S
Not good for two strokes, but good stuff
I bought this to patch a hole in my two stroke exhaust chambers. It worked well enough in the places that were completely dry and flat. Trouble is there arent many of those places on a two stroke exhaust. I think the oil soaked into the material. This stuff dries like a cement, so not great for my vibrating racket machine, but I think it held up well for what I asked. Took about 4-5 rides to start losing it. Was worth a try, probably work fine on a normal car exhaust. Maybe better if you can wrap with fiberglass. Dries quick, seems to be water based.
J**L
Worked well
Muffler tail pipe partially broke away from the resonator. This stuff completely sealed and secured the pipe back to the resonator.
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.
K**W
kanon
R**I
Amazing result. Used on an old gas oven door. Unable to get parts to repair handle but this product did the trick. Very pleased.
C**N
Super produit, A permis de réparer une fuite de boîte de vitesses.
J**A
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
Reparer un coude d’echapement sur un bateau le temps d’avoir la piece de rechange.
Trustpilot
2 months ago
2 weeks ago