PVC into cast iron sewer pipe


I need to replace a short vertical section of cracked 4" cast iron sewer line. The section to be replaced is a little less than 4 feet long. The top of the cast iron above the connection is already supported so it can't drop down when I take out the bad section.
What I am thinking of doing is breaking out the bad/cracked section of cast iron, and hopefully ending up with a clean male end of the cast iron at the top, and a clean female end of the cast iron at the bottom. To connect the PVC to the cast iron at the top, I plan on using a rubber connector.
My question is about the bottom part. I would like to insert the PVC into the female cast iron fitting at the bottom and then seal that connection with something. I am thinking that since it is a vertical connection, and it is not under pressure, this should be able to work without the fitting leaking. Is there some sealant or product that will work for this?
Is the alternative to look for a rubber fitting for the bottom that is big enough on one end to go over the extra large cast iron female fitting and regular 4" size on the other end for the PVC male end?
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http://www.buyhardwaresupplies.com/?t=5&itemNumber=43544
R
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I recently replaced cast iron pipes at my in-laws with PVC. I used a metal cut-off wheel in my 4" angle grinder and it was quick and easy to make clean cuts. Then I used a rubber "Fernco" style of coupling to connect the new PVC to the existing cast iron.
In my case, the cast iron was 4" and the new PVC was 3", so I slid a long length of PVC down the inside of the cast iron and used a reducing fernco coupling. It worked great.

If possible, I'd cut the female fitting away so you just have straight pipe on each end you can connect with Fernco couplings.

Until you get a plugged sewer drain, or it otherwise backs up. Then that connection would easily let waste flow out.

I think there are rubber fittings for adapting to female fittings, but I haven't seen them locally. You would probably have to check with a plumbing supply.
Good luck,
Anthony
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be sure to support the cast iron above before removing the section to be replace.
or the entire line may move, causing a rroof leak, cast iron is very heavy
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snipped-for-privacy@aol.com wrote:
...

...
...
Read _BEFORE_ posting, maybe???? :(
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might be a proper clamp, on the other hand it might be a small strap. people underestimate the weight of cast iron.
a buddy of mine did, he cut out a 3 foot piece that had cracked. the line had a strap holdinmg it in the wall...... well the line did stay in the wall, but it dropped 3 feet, left a big hole in roof, during a big rain storm. my buddy did roof damage trying to patch the hole. and fell off the roof. fortunately it was one story.
his wife had to hire a plumber to replace the line, get a new roof, the shingles were old anyway, my friend broke some bones and was off work for 3 months. his wife took the repair money out of his retirement account. she only half joked it should of been a 3 story homer, for the life insurance money........
he was bad news, and moved away after getting divorced.........
kinda dumb guy but I felt bad for him.
better to warn the OP.
cast iron lines were built from ground up, last section dropped thru roof......
most clamps were just sraps keeping lines upright so they couldnt fall out of wall cavity during construction. no need to support the weight
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snipped-for-privacy@aol.com wrote: ...

You've got the best stories for _everything_ I've ever heard, haller; I'll give you that...
My question would be if it had that much weight sitting on the section, how did he manage to get it out?
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copy and paste from OP. did you see this?:::::
The top of the cast iron above the connection is already

===============
wrote:

be sure to support the cast iron above before removing the section to be replace.
or the entire line may move, causing a rroof leak, cast iron is very heavy
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What's the benefit to cutting the hub away? It takes more time, presents risks that needn't be there, and the hub isn't creating a problem.
R
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Just a supply issue. If you can find the coupling to adapt PVC to a cast iron hub, great. I've never seen any of those locally, but standard Fernco's are easy to find. Unless the hub is part of a cast iron Tee or something, I see no value in keeping it. Cut back to straight pipe and use a common fitting.
Anthony
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I agree that does make more sense since the OP hasn't busted out the lead joint yet. I was under the impression he'd removed it clean to the hub and could simply use a donut. The donuts are standard issue, and any chain hardware store will give you the online price delivered to a local store if that works better for you.
R
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Well, I ended up doing both ideas.
At the top end, I had broken the damaged pipe out up to the point of the remaining hub that was still leaded to the incoming pipe from above that. When I looked inside, the pipe coming down into the leaded hub was damaged, so I left the hub in place. I'll look for a rubber adapter that goes over the hub and will also connect to the PVC that I will be attaching from below. I found that type of adapter at an ACE hardware store near me.
On the bottom end, I rented a soil pipe cutter and I used that to cut off the pipe leaving about a 4-inch piece that I will connect up to the new PVC with a rubber connector.
The soil pipe cutter was so-o-o cool! It worked like a charm. Since the part of the pipe leading up to where I did the cut was damaged, there was a chance that the whole thing would break, but I lucked out and the cutoff worked perfectly.
Thanks all for your help! .
wrote:

I agree that does make more sense since the OP hasn't busted out the lead joint yet. I was under the impression he'd removed it clean to the hub and could simply use a donut. The donuts are standard issue, and any chain hardware store will give you the online price delivered to a local store if that works better for you.
R
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Thanks all. The job is getting to be bigger than I planned so I may end up just having a plumber do it. It's in a property that I just bought (it was a bank-owned foreclosure) and now that I am working on it, I am finding that a little more of the sewer line is cracked than I originally thought. The pipe is easily accessible and breaking it away has been easy. But the leaded part of cast iron fittings aren't coming off too easily, and I am concerned that I may end up cracking the remaining good sections while trying to remove them.
Does anyone know if plumbers are able to heat the lead fittings enough with a torch to melt the lead and take them apart that way? If that's what they do, I may be better off just having them do that. That would prevent damage to the rest of the sewer line.
Thanks.
P.S. The stack above is supported very well, so I don't have to worry about it dropping down. There is a L-turn above the top of the basement foundation wall, and the L is supported directly on top of the wall. So, there is no way for it to drop down.

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It is often impossible to melt the lead out of the joint depending on configuration, and you will find a drill bit and chisel will make short work of removing the lead ring. With some of today's blades or a good chain wrench, it is easier to snap off the hub and use a "no hub" clamp.
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You can use a fernco at that end also. They make them just for that application.
s

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