Old cast-iron drainpipes: Maintenance?

Old 10-22-05, 10:39 AM
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Old cast-iron drainpipes: Maintenance?

Re: Old cast-iron drainpipes: Maintenance?


I belong to a little brick bungalow in the midwest, built in
'54, poured-concrete foundation.

Drainpipes are cast iron (lead/oakum w/hub).

I recently had to replace a 12' near-horozontal branch
(with pvc) that had rusted thru. Was amazed at the
50 years-worth of residual slime which was holding the
drain-water, insuring that the pipes were actively
rusting 24/7, 365 days/year.

What maintenance is possible/practical to preserve old
cast-iron drainpipes?

The cleanout plug is mounted on the largest drain pipe.
I doubt it's ever been opened: it's sealed with some
kind of clay-like gook that has hardened. Doesn't
wanna budge when I put a wrench on it. I should chisel
off all the ancient sealer, drown it with Liquid Wrench,
and open it with a pipe wrench?

Any/all info/sugestions etc much appreciated.

Old 10-31-05, 08:36 AM
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I'd like this question answered too!! My building inspecter told me of a product you can apply to the pipes to reduce the rust, but i haven't actually looked into it or heard any testamonials.
Old 10-31-05, 07:01 PM
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The problem with ANY drainline is the stuff they are subjected to. Soap, grease, chemicals etc. The slope of the pipe (1/4" per foot) is what is expected to move these things down the line to the sewage plant or septic. Problem is, each time some of this stuff goes down the pipe, a little builds up on the bottom and holds liquid. Thus, the beginning of a clog....or rust on cast iron.
I am a fan of enzyme drain cleaners. Such as Draincare. Enzyme cleaners cling to and "eat" things that are in the pipes. Unlike caustic drain openers which eat a hole and then travel down the pipes. This clinging/eating action keeps the pipes running smoothly. This means that water is not likely to "pool" in the bottom of the pipes.
Pudding man, those plugs are a bear to get out. You may have to take a hammer and chisel and use the edge of the chisel to "turn" the plug by tapping it in a counterclockwise direction.
Good luck.

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