Rust clogged cast iron tub trap

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Old 11-30-12, 07:39 PM
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Rust clogged cast iron tub trap

Slow draining tub in 1946 house. After a round of drain cleaners, used a snake down overflow. Only got as far as trap....stopped cold. Blocked overflow and plunged. Brought back lots of rust into tub, some pieces as large as the tip of my finger, but no soap or hair. (Tub hasn't been used for about 2years do to unresolved leak, which I handled this month. ) After several rounds of this, no more rust came out, but the drain was still just as slow. Can get to trap (doesn't have a clean out drain) from the bathroom below. The obviously rusted cast iron trap is connected to brass fitting from tub and galvanized pipe to sewer line some place under the concrete basement floor. The trap seems sound...no evidence of rust through or weak walls. How can I break through this rust clog? Thanks
 
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Old 12-01-12, 06:19 AM
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When you run water in the tub how long does it take for water to back up? Is it immediate or does it take 10 or 15 seconds?

I think snaking it is about the only option. You need to mechanically remove whatever is blocking the line. I would try a small hand crank type like you can find at many home centers. They are pretty flexible and might make the bends through the trap.
 
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Old 12-01-12, 06:32 AM
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Unfortunately, I've seen 2" cast iron drains reduced in size to near a pinhole from junk. The fact that you have not used it in 2 years means that all that stuff has dried out and hardened. You'll have to gain access to the drain area after the trap either at a junction or break, clean and go back with a no-hub fitting.

If you continue to run water, maybe you can re-wet some of the blockage and make your plunging more productive. How far is the run to the nearest vent pipe where it would marry up with the toilet drain?
 
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Old 12-01-12, 06:45 AM
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Rust cllogged cast iron tub trap

Hi. Backup is about 5 seconds. I did use the hand crank snake. Snake does have a drill attachment, which I used part of the time, but after the initial breakup of a big chunk of the rust, and pulling it out with the plunger, couldn't seem to get any more to budge. This was after working on it for over an hour. Exhausting! The overflow pipe does run directly down into the trap, so the first bend the snake encounters is the trap elbow. Normally the small snake shouldn't have trouble making it through a clean trap, right? That is what makes me think the rust clog is only in the trap, not in the galvanized pipe on the other side. Any chemicals or home brews I could use to disolve the rust without harming the brass or galvanized? Thanks.
 
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Old 12-01-12, 06:55 AM
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Hi. I'm not sure how far the run is to the vent pipe. A free standing shower in the basement bath and the walls on two sides of the shower and behind the toilet hide the terminus of the tub drain run. What is a no-hub fitting? Haven't seen that term before. Thanks.
 
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Old 12-01-12, 11:12 AM
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Use of no hub fitting

How, why, and where would I use a no-hub fitting? I'm totally out of my depth on this subject. Thanks.
 
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Old 12-01-12, 01:51 PM
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The solution may be to cut the cast iron pipe, clean out and put the whole thing back together again. To put it back together again, you will need a no-hub connection to join the two sections of pipe together.
 
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Old 12-01-12, 08:11 PM
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Cast iron drain trap

Hi. There isn't a cast iron pipe, just a cast iron trap between the brass tub drain and the steel drain pipe. Not sure there is enough space at either end of the trap to cut and re-attach with a no-hub. The 'U' goes directly to the cast iron ends that fit over the drain pipes at both ends. Can I cut the steel pipe on the down side of the trap to clean out the trap and then put the steel pipe back together with the same type of no-hub connector? Thanks.
 
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Old 12-01-12, 08:35 PM
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Can I cut the steel pipe on the down side of the trap to clean out the trap and then put the steel pipe back together with the same type of no-hub connector? Thanks.
Yes you can... But IMO I would get that snake through the trap. I use this. Sometimes difficult but never failed.






 
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Old 12-01-12, 09:15 PM
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Snaking cast iron trap.

Hi. I do have a similar snake with a drill attachment which I used with a helper for over an exhausting hour -Please see first post in thread - and can try again. But again I ask:any chemical helpers or home made brews to speed this up? I did use baking soda and vinegar followed by boiling water after the regular drain openers didn't work....it seemed to help a little. Thanks.
 
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Old 12-02-12, 06:08 AM
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Pour down the drain chemicals rarely help with other types of clogs, even the ones they advertise to dissolve. If you have rust clog mechanically removing it is about the only option.

Baking soda and vinegar is how you make a grade school volcano. Any benefit you might get from the slight acidity of the vinegar is neutralized by the baking soda. Remember, you are trying to dissolve the oxidized form of iron. Think of plopping a screwdriver in a bowl of vinegar. Not much happens other than your tool smells a bit like salad dressing.
 
 

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