Very likely to leak, zinc in the GI pipe will be contaiminating the weld and thus you cannot get a good weld.
This depends on the size and the location of the leak. It depends because a leak on the straight piece of the pipe will differ from a leak on the joint of the pipe. It also depends on the corrosion of the pipe and the extent as to how bad it is.
Trey sharkbite coupler if it is on a straight pipe. Use a good pipe cutter the size of your pipe. Plug in the coupler. It does not require any soldering. Check for the you tube video.
Trey sharkbite coupler if it is on a straight pipe. Use a good pipe cutter the size of your pipe. Plug in the coupler. It does not require any soldering. Check for the you tube video.
Repair the pipe of fixture to stop your leak.
I have a slab leak and I'm not sure how to repair it myself. I have read about epoxy pipe lining - is this good for preventing leaks in the future?
NO!
Yes, the gasket between the overflow pipe and the tub can go bad, or it can leak around where the pipe is attached to the drain.
Because there is a leak in the pipe of the water main.
It depends on the condition of the pipe. Corrosion could cause a leak.
Detect the leak and replace that part of the pipe. It is usually better to replace the whole piece of pipe. By removing the junk plastic and replace it with quality piping such as copper DWV or NHCI
Master plumbers.