Well you're driving down the road and notice that your car is making a loud noise. And that noise is coming from your muffler / exhaust pipe. That means that you have a hole somewhere and have to fix it.
Exhaust / Muffler Leak - Quick and Easy Hole Fix
This happened to me a few weeks ago. But mine wasn't exactly the most typical hole in the muffler. If it had been a small hole in a flat part of the muffler it would have been easier to fix. Unfortunately it was right at the seam/joint of the exhaust pipe.
Here's the last time i had to fix the exhaust. This was beyond fixing and needed replacing.
Here's the new muffler i got years ago.
One option would have been to un-bolt the exhaust and mufflers from the car, grind everything down, then try to weld the pipe solid again. But i thought that i would try an easier fix that wouldn't require removing anything from the car. I decided to try JB Weld.
This is definitely the cheaper and easier fix.
Now typically JB Weld is a 2 part epoxy that you have to mix together in equal parts. You squeeze out the same amount from the red and black tubes, mix it together and apply it to the area you want fixed.
The problem with this is that the liquid is a bit too runny for what i needed. I wanted more of a putty that i could roll and mold. Fortunately there is a JB Weld putty.
It comes in a tube - still 2 parts, the putty in the center is surrounded by a second layer. You just cut off the amount you need, mix together and you have a few minutes until it hardens. It only cost around $5 and gets incredibly hard.
I do recommend using gloves because after mixing i had the putty stuck on my hands for a long time. But the putty worked pretty well, i was able to wrap it around the entire joint to seal the hole.
One problem though is that there's a lot of exhaust gas pressure when the car is running. The JB Weld did help but didn't completely fix the problem. I think it's because the gas pressure pushed the putty up in a few tiny places. So even though it hardened, it didn't really get a good fusion with the metal pipe. Again if it wasn't in such a high pressure area, or had more of a flat surface to adhere to, it would have been fine.
But using JB Weld as a first thing to try is a good way to go. If it works, great. If it doesn't work, you are only out $5 and 30 minutes of your time.