In article ,
Karl Townsend wrote:

I've got a pin hole leak in a copper pipe on my hot water heat sytem.

Murphy is my partner. So, of course, the leak is right where the pipe
goes through the floor and you can't get at it. A proper repair is
going to mean removing the radiator above, cutting out a whole section
of pipe and replacing.

To avoid this job, does anyone suggest some sort of goo to just apply
to the surface of the pipe? Other easy fix?

Karl

Ain't no easy fix if the thing is leaking where it goes through the
floor, IMHO. Be sure to protect the new pipe from abrasion in the
floor-hole. Given that you'd need to pull the pipe to get anything on
it, no point in not just replacing it - paint won't do, and if you try
to slop enough epoxy on there to hope it will stick, it won't - the area
around the hole will be dirty and the epoxy will stick everywhere else,
making the eventual removal of the pipe more difficult when it still
leaks. For an accessible leak you can clean and shut off the water for,
epoxy can work.

Radiator stop-leak (the automotive product) might just work, and might
just cause other side effects you'd rather not have in your heating
system. There may be a version intended for heating systems with less
side effects, but it's a kludge in any case, not a repair.

If accessible, a tight wrap of waterproof electrical tape can hold up
far longer than you might expect (on a well-cleaned pipe), but it's not
accessible...

--
Cats, coffee, chocolate...vices to live by