Black iron sewer

[Chuck52]

My 45 year old house has black iron sewer pipes. All seems to be in pretty good shape, but the two-inch line that drains the kitchen sink gets plugged sometimes. Hmmmm. I wonder if could be because the wife insists on putting grease down the drain and using the garbage disposal for anything that falls in the sink.....Nah.....can't be that. Anyway, there are two clean-outs on two male-female black iron fittings stacked on top of each other right above the basement floor. The clean-out plugs are brass, and they are not coming out without dynamite. I suspect that we get problems when the melted and dissolved greasy stuff hits these joints and plates out, and then traps whatever stringy stuff the wife has just dumped down the disposal. I'm thinking about replacing these fittings and the pipe above them with PVC and a nice user friendly clean-out, but I don't know how those old black iron to black iron joints were made. Are they threaded, or did they fill the joints with putty or lead or something? I certainly don't want to damage the pipe that goes into the basement floor, so I might just cut out a section of the black iron pipe and put in some PVC. That would leave me with whatever joint is collecting the crud, but with a convenient clean-out I could live with that. At present, I get up on the roof snake down the vent, because it's a straighter shot than going through the kitchen drain, and I don't have to disconnect any fittings. Last night, that didn't do the trick, but I dumped a half gallon of Liquid Plumber down the vent and after it sat all night the snake popped the crud out this morning. While that's entertaining and all, I figure the next time will be during a blizzard or something.

Chuck

 

[GrayBeard]

Chuck,
If it's cast iron pipe and fittings it's probably hub and spigot with leaded joints.
If it's threaded joint, there will be a small portion of the thread exposed against the shoulder of the fitting.
No matter what kind of joint it is, you just need to get a straight run of pipe ( 6" is plenty) as close to where you want to start your replacement and cut the existing pipe out
Then install a Fernco coupling of the appropriate pipe size to the remaining stub and go to work with whatever kind of pipe you wish to use on your new installation.
The couplings are easy to use, durable and available at most plumbing supply houses.
GrayBeard

 

[MarkLeininger]

You have one other option, and that's to destructively remove the brass plugs. You can easily drill through it and break it out in pieces, the problem you might have is that the threads on the cast iron have been so damaged over time that you'll never get a new plug to seal. Since cast iron is much quieter than PVC and it won't cost you anything to take out the brass plug, I'd do that first. If it seals great, if not you're no worse off than you are now.

Since the fittings are right above the floor, you'll either have to remove them, or cut the pipe above them and install PVC fittings with cleanouts on them. I would vote for the latter. If you're determined to get them out of the floor, they're put in with lead. You can take a drill bit that's small enough to fit into the space between the bell and the pipe and just drill the lead until it's all mostly gone, then you'll be able to pull the fittings out of the floor fitting. But now you'll have to lead in a cast iron length of pipe into the floor fitting because there's no way I know of to join PVC to the bell. Once you do that you can use a Fernco to attach PVC to the new cast iron pipe.

 

[Chuck52]

Thanks gentlemen. I think I'll probably go the way of just cutting out the section of pipe and using the Fernco fittings. When I do that, I'm going to try to figure a way to make it easy and neat to drain the pipe above the new clean-out...maybe have a valve coming off the clean-out or something.

Chuck

 

[Junkman]

I would suggest that you dump some lye powder into the pipe from the roof and then pour some boiling water down the pipe. This will clean out the grease and get things flowing. I wouldn't recommend cutting the pipe unless you absolutely have to. Remember, that this pipe didn't clog for many years and once it is properly cleaned, it will be fine for many more years. I had black cast iron hub fitting drains in my old house and they were there for at least 75 of the 125 years that the house had been standing is my guess. This is what the plumber recommended to me when the drains started to run slow. It worked and I never had another problem for the next 6 years that I lived there. Just be careful with the lye and don't inhale the fumes. Cap all the sink drains in the house with wet rags before doing this. Good luck with whatever you decide to do... If you decide to cut the pipe, see if you can borrow a hub and cast pipe cutter from a plumber to make the cut. Lot easier with the proper tools..

 

[Chuck52]

Junkman,

I suspect the half gallon of Liquid Plumber I put down the vent, which then sat for about 12 hours, did a fair job of cleaning the crud out of the pipe. The dry lye might do a good job on the horizontal runs, but I wouldn't think much of it will cling to the vertical surfaces. When the plug let go, I did work my snake up and down the pipe many times in the hope that would dislodge more of the gunk on the walls. Actually, most of the pipe should be fairly clean after the treatment I gave it. I do like the idea of keeping the old pipe intact, since, as you said, it's been working OK for 45 years. If I can get the wife to try to limit how much stuff goes down the garbage disposal (which obviously has not been there for 45 years) I may not have problems for quite a while. We're going to have the kitchen remodeled some time in the not too distant future, and at that time perhaps I can have the plumber I'll have to hire anyway see if he can open one of the clean-outs on the iron pipe.

Chuck

 

[Junkman]

If you can get the clean out loose, they make a threaded lead clean out plug. There is a 1" outer diameter that is threaded with a steel center. This is great for damaged threaded clean outs. The plumber should know just the right amount of heat to put to the pipe to get it to expand and allow the clean out to come loose. If it comes out without damage to the clean out threads, when you put it back, use some Teflon tape. Will keep things from sticking. Also, ask the wife to run the hot water after grinding with the garbage disposal. This is what we do and there is no problems with the pipes. Also, try to get her to put grease into a can that you keep in the freezer. When it is full, then just toss it. Wiping out greasy pans with a paper towel before washing also helps to keep things clean. I know that wives are hard to train, but a few can be reprogrammed when they see imminent danger in what they are doing. Just keep my name out of it. I have enough grief with my own... /forums/images/graemlins/blush.gif /forums/images/graemlins/blush.gif

 

[bgott]

If you do cut the iron pipe I would make sure it's secured first. It would be a sickening feeling to knock the cut out part out and have the upper part drop a couple of inches. The last one I did I heated a length of all thread and bent it into a U- shape and then stacked a couple of shims between the nearest studs and then U- bolted the stack to the studs before I cut it. I say "studs" because you have a double wall when they run a 4" stack up inside it. I don't know if it was secured higher up the inside of the wall by anything other than the wyes or ells but I wasn't taking any chances.

 

[GrayBeard]

If you can get your hands on a cast pipe "snapper" as junkman stated , it may make the job easier.
Just be careful, on old cast and unless you have some experience you can crack or crush the pipe.
You'll need a relatively square edge to start your new work.
I think in the first post you were talking about 2". Most any saw with a good metal cutting blade should work fine.
GrayBeard

 

[Currmudgeon]

I've cut the stuff with skillsaws, sawzalls, and a hammer and chisel. The latter is a great way to shatter the pipe. Don't ask how I know that. /forums/images/graemlins/shocked.gif

I think I'll agree with everyone who says to try to save the existing cleanouts. Brass vs iron sometimes corrodes up solid as a rock, but if you can tease the old plug out, or cut it out without buggering the threads too much, that's the way I would go.

Then clean the threads with a wire wheel and teflon tape the new plug. With clean threads and a wife who flushes grease down the drain, you should have an excuse to exercise the cleanout plugs and keep them from siezing up. /forums/images/graemlins/smirk.gif

If the threads are trashed, you may be able to do with an expanding plug. I suppose it's too much to expect the threads on a plastic cleanout to match the CI, but if they do, that's a joint that will never sieze.

I think Fernco makes a donut to allow a PVC pipe to stab into a CI bell. I know they do for ductile iron, but that has a different dimensioned bell. I think you could also make up an adequate joint with oakum and lead wool, oakum and epoxy, or oakum and butyl caulk. It's not a pressure joint after all.

Personally, I'd prefer to keep the cast iron as long as I could.