The answer to 'my pipe repair smells bad' is that a smelly pipe repair is often caused by a leak or improper sealing of the repaired area. This can allow sewer gases to escape and create an unpleasant odor. The most common causes are using the wrong type of pipe sealant, not properly cleaning the pipe before repair, or not allowing enough time for the sealant to fully cure.
If you notice a foul smell after repairing a pipe, first check the repair area for any signs of leaks. If there is no visible leak, try running water through the pipe to see if the odor goes away. If the smell persists, you may need to redo the repair using the proper sealant and techniques. However, if you are not confident in your ability to properly reseal the pipe, it's best to call a professional plumber to inspect and fix the issue.