J-B Weld 37901 ExtremeHeat High Temperature Resistant Metallic Paste - 3 oz

Used this to patch a crack in my muffler on my 150cc scooter and so far it has worked perfectly! I live in North Texas and it's June, so it's pretty warm out even in the evenings, so I had no problems with cure time. Started to harden within a few minutes after application.I did have to mix up the product pretty well before it was ready, but that was easy. It doesn't come with something to stir/apply it, so I used a small spatula that came with another weld glue product.Seems to be holding well even with high temperatures. If it fails I will update this review, but so far so good!

Got this to fix a exhaust leak and to my surprise it works good but I’d say buy 2 and lay it on extra thick just in case seals great super easy to use I had mine right up near the engine so heat did nothing to it but make it stronger

Little hard to use at first but it works and does its job

this stuff works!!had a small hole in the exhaust header of my truck. about the size of a dime. I opened the package, stirred it around a bit (settled during shipment, etc.) applied it direct to the header and that was about 3 weeks ago. Still holding strong. The exhaust headers on the motor probably get up to the 700'ish degrees F at the least. So high heat, good bond, works as advertised! Also, i did sand the area to bare metal before applying, I'd recommend this just to be sure to get a good bond.

so far it is holding, will see when it actually gets hot.

I prepared all surfaces with a Dremel with and wire brush attachment. All surfaces became shiny, clean metal.First impression of the product - very small. It says 3 ounces, but that's by weight, so obviously much smaller than 3 fluid ounces. That said, it also weighed less than 3 ounces on a tested scale even with the tub included, so I feel like I've been cheated.Next point: it was a thick, dense paste, not the liquid you see on the videos. I would guess that was because the foil was damaged or not properly sealed. It was the correct color: separate tan/black before mixing and cement gray after, but mixing took quite a lot of effort, because it felt like nearly cured cement when mixing.I did each step quickly, with no time between opening, mixing, and applying, so as not to allow it to cure prematurely. Being a nearly-dry cement consistency, It didn't want to adhere at all when applying it to the clean metal. I forced it to stay on by placing wood objects to keep it in place.I waited around around 30 hours. My setup to keep things in place worked. The epoxy became completely dry, but not strong at all. The very light metal parts separated with almost no effort beyond the parts' own weight. I was attaching a very light heat shield to a vehicle floor. The heat shield had two good bolts already holding one side and middle; I was just attaching the other side where the stud had broken from the vehicle floor. The bond didn't even last long enough to give the vehicle a test drive. The epoxy was just barely stronger than a dried sand castle. Strong enough to hold its shape, but noting else. I can crumble it with my fingers despite it having been given time to dry completely.In closing, this job took a lot of time and effort, and it was quite frustrating and discouraging to see the results. I will attempt to return this to the seller. Regular JB Weld has been good stuff, but this extreme heat version turned out to be a total failure.

So i got a car with a cracked engine block, it was leaking coolant. I thought i give high heat a try, even though the coolant doesn't get that hot. Anyways, the problem with this stuff is it ONLY cures when under heat! I let it cure for 16 hours, and it came right off of the block. So i tried again and let it sit for about 36 hours, plus some time with a heat gun on it. That didn't work either!I ended up using normal JB weld and let it dry overnight. That worked.

Easy to use and works well