Stuff We Use: JB Weld Exhaust Wrap

On our never-ending quest to improve this place by listening to feedback from the B&B, we are taking a new tack with these product posts, choosing instead to focus on items we use and have purchased with our own meagre income. After all, if we’re giving you the truth about cars, we ought to give you the truth about car accessories.

This time around, we’re quite literally wrapping up a repair on an older vehicle whose exhaust system seemed just fine until it wasn’t.

As tends to happen with cars of a certain age in places like the Rust Belt and North of the 49th, an aged economy car in our fleet with 350k on the clock experienced a sudden and deafeningly loud failure. Guess the old saying of rust never sleeps is deadly accurate for wide swaths of this continent. In this case, a hole about two inches in diameter appeared right on a flange connecting the flex pipe and catalytic converter. Given its location just a short distance from the engine and ahead of not only the muffler but also the resonator and catalytic converter, the thing sounded like a derby car.

That can be a tough spot to repair thanks to its location but, thankfully, the hole was not on the catalytic converter, so messing with that infernal device wasn’t necessary. But how best to repair a hole sized about the width of two quarters on a curved section of pipe next to a flange? The old trick of cutting up cans and securing them with a couple of clamps won’t work in this case, even as a temporary fix, thanks to the shape of the area. Nor would any MacGyver’d or field expedient repair of that type for the same reason. 

Enter the solution of exhaust wraps. While it sounds like the equivalent of dubiously beneficial products like “tune up in a can” and other malarkey, this stuff can actually produce decent results. There are two general types of wrap: one is a dry wrap which is supposed to cure by way of hot exhaust temperatures, while another is wet like plaster and can cure on its own.

After trying the first kind and watching it blow to confetti in less than 24 hours, the product you see on these digital pages was picked up on eBay for about 25 bucks. The wrap itself, measuring a couple of inches wide and about six feet long, was shipped in a foil packet filled with the plaster-like goop. Kneading the unopened packet for a few minutes worked the goop into the fiber wrap, at which point it was ready to apply after removing whatever loose debris was on the area of repair.

Manipulating a soaked piece of fiber was messy, as one would expect, so JB Weld helpfully includes a pair of disposable gloves. It’s also probably not a great idea to get a lot of this stuff on yer bare hands. The soaked wrap was easy to maneuver around the damaged area, overlapping in places to assure a good cover and being creative around the flange area. The six-foot wrap was plenty for this repair. Instructions say one can either operate the engine for about 20 minutes to cure it via exhaust heat or simply let it sit for a couple of hours. We did the latter, actually letting it cure overnight. A small amount of silver tape is included to wrap around the repair during the curing process and should be removed after the wrap has hardened.

It’s been exactly two weeks since this repair and everything is holding as promised, so we’re willing to call this one a win. For the sake of 25 smackers and 25 minutes lying supine under the car, it’s a great solution (for now) compared to torching off a rusted flex pipe and welding in a new one. The rest of the exhaust system was replaced by the car’s previous owner just months before we bought the thing.

As planned, this series of posts will continue to focus on items we actually use and have bought with our own money. We hope you found this one helpful.

[Images: eBay]

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