I am having to replace some leaking sections of copper pipe in my house & 1
part of the original pipe doesn't seem to want to accept solder. I have
cleaned both the pipe and the couple with sandpaper, put flux on both the
pipe and the interior of the couple, etc. but I can't seem to get it to hold
water. All of the other sections are fine--it's only at the original pipe
closest to the entrance to the house. The pipe is 3/4" copper & was probably
installed when the house was built in 1978.
Any ideas why this is happening? I have cut out & redone 3 times with the