Our cast iron waste line dates back to 1895!!!! We have replaced all the waste lines in the house with new PVC except for the short stub that goes through the foundation wall (and continues out deep underneath our yard to the street main sewer pipe).
However, the stub which consists of about 1 foot of cast iron pipe and a cast iron hub has extensive rust on the inside along with some visible on the outside. There also appears to be at least one hairline crack running through the hub with some evidence of (minor) past leakage. During our 4 years of owning the house, we haven't seen any leakage (or blockages for that matter).
Due to the expense of excavating the yard, we would like to avoid replacing the pipe for as long as possible. I know that some firms can put an epoxy condom in the pipe but that also is not cheap.
Is there any stop-gap way to "strengthen" the pipe to prevent it from cracking (or leaking further)? Can anything be done to minimize or impede further rusting?
I was thinking of something like: - Use a steel brush (or wheel) to remove the exterior rust and help identify location of hairline cracks. - Fill cracks (and other suspect areas) with JB Weld expoxy. - Spray on Rustoleum primer for heavy-rusted metal - Spray on topcoat of white paint (mostly cosmetic here)
Will the above work/help to prolong the life of the remaining cast iron pipe and lessen the risk of a more catastrophic crack developing out of the hairline crack?
Any other suggestions?