PC Plumbing Epoxy Putty for potable water 57g

PC-Plumbing™ Epoxy Putty is for pipes. Use PC-Plumbing™ to stop leaks in less than 60 minutes. Pre-measured and easy to use and 2 part epoxy putty does not require tools. Hand mix and apply. NSF® approved for plumbing repairs and for contact with potable water supply pipes. 

Here are just a few specific uses (there are hundreds of other uses):

Seal leaks in copper pipes resulting from hard water
Fix freeze damaged PVC and copper pipes
Stop leaking copper elbow and tees
Fill abandoned drill holes in ductwork
Insulate electrical connections from water