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Ot- how to work patching into cast iron septic pipe.

Trboatworks

Diamond
Joined
Oct 23, 2010
Location
Maryland- USA
I have to cut out the cast 90 septic pipe and replace with PVC.
The 90 is cracked and leaking.

Any plumbing savvy folk here.

I guess I need to replace a street 90 right to where it is inserted into the bellmouth of another street 90 which is buried in grade.

Crap- literally.
I can go cry at the parts desk of a pro plumbing supply outfit but anyone know how this transition can be made up?

Are these joints lead sweated together?
I was rather thinking I was just doing a rubber clamp on collar made for iron to PVC but would need to trench further to get to straight pipe.

Maybe the best move is to cut grade back till I reach the straight pipe run and splice in there..

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Buy the interface coupling to convert from cast iron to PVC. It's just a rubber coupling that uses hose clamps to connect. Last one I used lasted 30 years and then the place was torn down,

Just cut the cast pipe in a straight section 90 degree cut, smooth the cut and bumps to prevent damage to rubber coupling. Don't over tighten the clamps.
 
Ok- so I have to get past these two street 90’s then.

The first one is as shown- vertical sweep out through wall, the second is horizontal plane turning 90 to head off property.
 
all the cast drain pipe I've ever seen used lead packing. Back in LA, at least, there were certain things that had to be done by a licensed plumber. Try that first, cause it's a shitty job. (got it in first)
 
Typically lead/oakum at the bell joint.

Have not done it myself, but watched it done and believe it can be sweat out with maap torch. But then you're stuck with the bell mouth and I believe therefore stuck with using lead/oakum to put in a new 90. Not impossible DIY but you'd need lead, oakum, a lead ladle, and this odd fireproof 1/2" thick 'string' to contain the lead at the joint while it cools. At which point maybe it's best to use a plumber or cut the slab back to a straight pipe that you can use a rubber pvc transition collar on.

And ditto Larry's comment. In the areas I've lived that would technically require a licensed plumber.
 
Did this at my dads house. House is over 150years old and Im pretty sure it was not the first time it was worked on so we may have been working on others mistakes. Pipe was not soldered but had lead packing and something call oakum. Joints want to rust together and the ends of the pipe were corroded crumbling. Had to dig back to find good pipe, then use a chain cutter aka snap tool to cut the cast iron pipe. As was stated before use the rubber hose clamp splice and replace with pvc.
 
This damn old house...
There are two or three abandoned cast septic lines in the grade plus a old clay line.
Hard clay- I think it is tough on pipe..
110 yr old house...
 
The rubber seal designed for inserting Sch.40 plastic or iron pipe
into a cast iron "hub" is called a "donut" down at the plumbing supply house.
 
If there is enough good straight of the cracked elbow to let a Fernco coupling grab there, cut off with a reciprocating saw, sand the pipe as smooth as possible and couple to PVC or ABS back to where it is convenient to splice. Fernco couplings meet code in most places.

Fernco Flexible Couplings and Adapters | Fernco - US

The bell mouth cast iron connections are made by packing oakum into the opening, then pouring in molten lead, then caulking around the joint with a dull chisel to force the lead against the cast iron joint.

If the plumbing is sound other than the crack, you could dry out, wire brush to sound metal, wrap like a mummy with fiberglass cloth and polyester or epoxy resin, cover it up.

I had a long crack in the bottom of my in basement cast iron sewer pipe due to freezing. I flushed with lots of clear water, heated with a heat gun until the crack was dry, packed with cast iron JB Weld, quickly put on hose clamps at about 8 inch centers, let set overnight. This has lasted about 10 years so far.

Last resort for you, call plumber, write check. Good luck with whatever you do.

Paul
 
Typically lead/oakum at the bell joint.

Have not done it myself, but watched it done and believe it can be sweat out with maap torch. But then you're stuck with the bell mouth and I believe therefore stuck with using lead/oakum to put in a new 90. Not impossible DIY but you'd need lead, oakum, a lead ladle, and this odd fireproof 1/2" thick 'string' to contain the lead at the joint while it cools. At which point maybe it's best to use a plumber or cut the slab back to a straight pipe that you can use a rubber pvc transition collar on.

This is not hard to do. I replaced a damaged toilet footing in my old house (60+ years old) and I needed a new cast iron flange, as it was in the lower level of a split-level and I was not about to start chipping at the foundation to make room for a PVC transition. The old one came out with a surprisingly small amount of fighting, mostly just a simple mapp plumber's torch and a pair of pliers working back and forth. The treated hemp rope is not all that hard to find, and melting lead can easily be done with the same torch you started with. A steel soup can with the rim bent out and a pair of channel locks would be fine as a ladle.

If you choose to do this, don't forget to use a cold chisel to peen the lead after pouring! This is what sets the joint, the expansion of the soft metal fills in all the gaps and induces a resilience similar to work hardening.
 
I’d like to replace/get replaced the cracked 90.

Very good info above- I will ponder a coupling on the good leg of the street 90 or maybe look at doing a insert of PVC into ‘hub’ with a ‘donut’.

Thanks for the parts names- that helps.

Wicked hard access here-!
Under concrete walk tucked into corner etc etc.
Cutting into grade to get past the horizontal street 90 a royal PITA..

Man up eh..
 
Old time plumbers will have a tool to cut iron pipe. It looks a bit like a roller chain but has cutting wheels along its length. It is wrapped around the pipe and then tightened with a handle until it fractures off. It can get into close areas fairly easily.
 
You have to get under the cut pipe and use a wire brush on the outside. It has to be fairly smooth and clean on the outside so the rubber boot can seal. If it does not seal it will leak and roots will grow into the pipe. I used an angle grinder on mine.
 
Looks like it has been cracked for a long time- there was sort of a poured over lead cast on the crack.

The crack is four inches from the socket in the hub.
Fernco wants the hub measured to within 1/32” to purchase correct donut...

D029DD7C-7977-441B-B455-80FF784A9BBA.jpg

B6F1468D-1EE7-4CC0-8952-0266A0EB5B39.jpg

The cleanout stack is a mess:

02D29907-5B18-44BC-9686-1FBF89E8EF95.jpg

Looks like the way forward is a swept plastic 90 right to that hub.
 
You can transition from the cast hub to schedule 40 by removing the 90*sweep and cleaning the hub and place your schedule 40 into the hub and pack with oakum and seal with Hercules plastiseal (if I remember correctly). You wont find a sched 40 sweep like that cast , you'll have to use a 4" 90 and a stub of straight into the cast hub. Of course, while you're there, you'll want to get some 4 x 2" directional tees and straighten that "mess" out, or..call a plumber and work out a trade...you fix his boat and he fixes your poopy pipe. PB
 








 
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