J-B Weld37901 ExtremeHeat High Temperature Resistant Metallic Paste - 3 oz

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.

(Picture is this product with more JB weld steel stick above it) Good price tag, good product, and does its job. It does really well to prevent leaks on blocks, even aluminum blocks as well, this block had a crack and was leaking oil, but after applying the extreme heat with more jb weld thats steel stick, it held up amazingly. No leaks, holds tight and strong. It was also really easy to apply, a bit messy and stinks but nothing to unusual, and dries until a few hours so its best to give it time to cure, will be using again.

Worked great on one of out gas grill burners. But, went to use it again three weeks later to glue a plant hanger and, it was dried up. Love the product but, 8 dollars for a minor repair gets pricey. Cheaper in the long run for me to buy new burners for the grill.

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!

Worked really good on cast iron bought more to fix holes and cracks

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.