We are renovating an old house that has a septic system. The pipe to the septic is cast iron. How can we change this pipe to plastic pipe?
Actually, this is not a big problem. The cast iron pipe hub should be either cut off with a reciprocating saw with steel blade or by renting a large cutter for cast iron, if you have the room. I have done this a few times using the recip saw. Just a warning - cast iron pipe is very hard, but also very brittle. It can be broken with a hammer. Once the pipe is cut off a "mission" fitting, a rubber fitting that slips over the pipe and fastened to the pipe with stainless steel clamps, is used between the cast and the ABS or PVC. Here is a pic of one:
These fittings are the heavy duty rubber with s/s clamps not to be confused with the mj - mechanical joint couplings, which are much lighter and not approved for burial. They may need rubber bushings to match different sizes of pipe, such as 4" cast to ABS, or 4" cast to PVC.
These fittings are generically called Mission, but Fernco is also a brand in my area. Your retailer will know which one you need and the size of bushing if needed, too.
Dave(Ask Dave) (About Dave)
Hi, I'm Dave Osborne. With over 50 years experience as a journeyman carpenter, foreman and contractor in heavy construction I enjoyed working with apprentices and sharing the tricks of the trade that others shared with me. Now I get emails from Members all over the world and we include many of my answers in our Free Monthly Newsletters. Some of my answers include drawings and instructions specific to a project, but may also answer your questions. I use correct construction terminology, so you can confidently inform your building supply dealers or contractors exactly what you need.
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