Cast Iron Pipe Repair?

[Kevin]

Greetings all!

Does anyone know if something exists that can be used to repair a leaky cast iron drain stack? Basically, what I have is a nearly 40 year old cast iron pipe that has formed various pin-sized holes from which waste water leaks resulting in a rusty mess on the basement floor (it's gradual, but does accumulate over time). Before I go through the trouble of having the pipe replaced, I wanted to look into repair solutions. What I am envisioning is some sort of putty that will adhere to the pipe, is water resistant (or better yet water proof), and preferably can be painted. I've experimented with epoxy glues, but none set fast enough to prevent water from bubbling up underneath. The glue eventually fails.

The problem is that I cannot go for too long without running water through the pipe (flushing toilets, running water in sinks, and so on), so there is never enough time for the glue to dry completely (nor enough time for the pipe to dry enough to apply the glue, I figure).

Any ideas?

Thanks, Kevin

[Jack]

If you at least four minutes drying time and the area isn't hugh you probably can fix it with "J B Weld' Kwick set".. Then there was a product that I never knew the name of that would do the trick. It was and still may be used to seal aircraft tanks during WWII when they were pierced by bullets. it was self sealing. It had a brand name of "Prestone" on it.. It was a black compound putty consistence and would adhere to anything and was resistant to water, gasolene, oils etc. I think lacquer thinner was only solvent that would touch it. I've not seen it on local markets but aircraft supplies may still carry or an inproved product. It definitely would do the trick.

[dpb]

You know the real answer, of course, already... :)

As you patch one pinhole, another will break out. If the cast is this badly corroded, it's inevitable that it will finally fail in a large enough area that you may as well figure on replacement.

The bad thing is if an exposed area is this bad, that that's in the concrete and underground is probably worse. You may already have a forming cesspool under the basement floor. I'll not tell the story of what we found at the church when replacing an old urinal the valve had failed on... :(

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[Kevin]

Yeah.....

I'm already seeing this to a degree. I managed to get some of the epoxy to set in one spot blocking the leak. Not far from it you can see little beads of water starting to form.

No...please don't...I'm depressed enough already! ;-)

But, my next question would be the whole replace with PVC or cast iron again. I know this has come up before though, so I won't even bother asking it....

[dpb]

...

:) Slick! I like it... :)

In general, it's far simpler and cheaper to replace waste lines w/ plastic instead of cast.

If you can find a location upstream of this bad section that is still in pretty good shape, making the transition would be relatively simple w/ a Fernco or other coupling.

The question is where the drain goes after the floor and what it will take to do it that likely really will need looking after sooner rather than later.

One presumes given the description and problems, this is a fairly old, probably original, installation...

Good luck. You may be able to limp along for a while yet, but probably best to be planning on the replacement before too long.

[Bob F]

That might depend on how much you enjoy hearing water rush by whenever anyone upstairs flushes.

Bob

[Bert Byfield]

Out with the bad pipe, in with the PVC of about the same diameter and length, connect with rubber pipe-clamps that slide over the PVC and iron junction, tighten with a screwdriver, done.

[Kevin]

Oh yeah, I'm fully aware of how noisy PVC can be, and I'd much rather go with iron again, but....

Of course, I could just paint a mural of a waterfall on the plastic and go with a Hawaiian theme in the basement! Could be soothing!

[Kevin]

Much of the upstream pipe has already been converted to plastic (or is still the old lead stuff). When I remodel the master bathroom, I'll end up replacing the rest with PVC, which would leave only the main vertical stack to content with (mind you the master bath is a few years off, and I'd prefer to take care of the rest well before then).

The case iron is most certainly original. What gets me is that I've heard quotes of up to 100 years life for the stuff (probably in this newsgroup), yet mine is already failing (*already* is relative, mind you). Of course, I'm sure the previous owners did nothing to help the situation.

The drain pipe actually exits the house about a foot off the basement floor (and leads to a septic tank). I could conceivably dig down far enough on the outside to find it. Since the a large portion of the basement foundation is exposed on that side, I may only have to go down a couple feet. While I don't like the prospect of having to repair that, it's not totally out of the question. Could be a good project for a hot midwest summer afternoon.....

Cheers! Kevin

[N8N]

if you leave cast iron above the pvc it needs to be supported somehow BEFORE cutting...

nate

[dpb]

Actually quite similar geometry to this house. More than likely (I'd say greater than 50/50, probably like 75/25) once through the wall the cast turns into tile.

This house is 90+ and the remaining cast all seems as good as new. All except the last 8-10-ft of the main stack and exit was replaced when Dad remodeled. Local water conditions and use make for a wide variability.

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[Kevin]

Thanks Nate.

I'd say that if I replace it, no matter what I go with, I'll end up replacing all of it (that I can easily get to that is). But, most of the upper stuff is already supported by straps nailed to the joists.

I am curious, though. Did you learn this the hard way?

[James "Cubby" Culbertson]

You could weld the holes shut although as many have already said, you're better off replacing it. Cheers, cc

[Big_Jake]

Really? You good at welding CAST IRON? My dad is a retired welder, and couldn't weld cast iron, even after 37 years on the job.

JK

[dpb]

Well, yes cast _can_ be welded, but takes correct rod, heat, etc., and, like any other specialty, some training helps. Like various stainless, some are more amenable than others.

Biggest problem other than simply technique and material is if it's so thin it's leaking through the wall, it'll be no better than the patch up w/ epoxy or anything else--one spot fixed, another will soon pop up...

Just got the compressor sheave back from the machine shop today -- they welded in filler where it was hogged out from set screw having worked loose and rebored the hole and cut a new key groove -- it's cast.

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[James "Cubby" Culbertson]

Plenty of things that are cast are welded. You have to be careful with preheat and post heat, correct rod/wire, etc... but yes, with the right procedure, it's not that difficult...just time consuming. Would I bother on this application? No. The welds are only masking a small part of the problem that will surely surface in other places. Cheers, cc

[Stormin Mormon]

Rolls of duct tape, spiralled, and overlapping. Lots, and lots of duct tape.

That, or the new wide UV resistant tape at Johnstone. It was made for outdoor patches, but may work for this.

[DanG]

The big problem in replacing cast iron pipe is doing the cutting. Choices: grit edge blade in a Sawzall (slow), gasoline cut off saw with abrasive wheel (noisy, dirty, moderately dangerous), a weld cutting wheel in an offset grinder, chain cutter. If you're lucky and careful, it can be cut with a cold chisel and hammer.

The joints can all be done with no hub clamps. You've not indicated whether there are fittings involved, but even they are easy with no hub fittings and clamps.