Sealing 4" Cast Iron to 4" PVC

Reply

  #1  
Old 01-16-08, 04:05 AM
M
Member
Thread Starter
Join Date: Jan 2008
Location: West of Chicago
Posts: 327
Received 0 Votes on 0 Posts
Sealing 4" Cast Iron to 4" PVC

I want to remove a cast iron elbow from my stack and replace it with a PVC elbow. I guess I am going to drill/dig out the seal, which seems to be a dark grout looking stuff. When I install the new elbow, what is the best way to seal it up again? Where can I find this "rubber doughnut"? And this gets packed into the hub, much like oakum? Any top sealer needed, like RTV silicone?
 
Sponsored Links
  #2  
Old 01-23-08, 02:09 PM
D
Member
Join Date: Jan 2007
Location: Stafford, VA 22554
Posts: 114
Received 0 Votes on 0 Posts
Sealing 4" cast iron to 4" PVC

Home Depot or Lowes have rubber boots in a "T" shape for this. Rent the tool that will score the cast iron pipe and cut it at the same time.

The stack needs to be supported (metal pipe straps) before you cut it if it is not already supported.

The boot come with clamps to make it tight around cast iron waste pipe.
 
  #3  
Old 01-23-08, 02:44 PM
Terd Herder's Avatar
Member
Join Date: Jan 2008
Location: Northern Illinois
Posts: 301
Received 0 Votes on 0 Posts
If you are going to replace a CI 90 (elbow) you will need to cut the cast iron pipe 10-12 inches from the fitting on both ends. Use service snappers. It should come out in one piece. You will not have to dig anything out of any hub.
Get a PVC elbow, and some PVC pipe, glue and primer.
Hold the PVC 90 up to the cast iron 90 that you cut out. Pre-fab an exact replica out of pvc. If you are an 1/4 inch short on each end it is ok. This will allow you to fit it in better. Technically, you should buy no-hub bands and adapters, but you should be ok with 2-4inch no-hub bands. Be sure to support the cast iron, because when you cut it, it will snap, and you dont want any shifting.

Good luck, it can be a big job depending on the setup of the pipe and certain existing conditions.
 
  #4  
Old 01-24-08, 03:32 AM
M
Member
Thread Starter
Join Date: Jan 2008
Location: West of Chicago
Posts: 327
Received 0 Votes on 0 Posts
Hey guys,
First off- Thanks alot for the replys... I will be attempting this project this weekend. We are a little behind scedual (who isn't?) but this part is fast comming!

I guess I wasn't very clear as to my situation...

The hub I am talking about is on the stack itself, and although I could cut out a section of pipe, it seems better to just remove the sideways-facing 90 and replace it. Can I still get oakum and lead?
 
  #5  
Old 01-24-08, 03:40 AM
M
Member
Thread Starter
Join Date: Jan 2008
Location: West of Chicago
Posts: 327
Received 0 Votes on 0 Posts
Sitting here thinking about it...
Would it be advisable to replace the whole stack, leaving a long CI stub in the basement floor and another stub from the bathroom ceiling? I can get into the attic to put a clamp on the pipe before it passes into the bathroom. Or should I just replace the section w/ my Tee? This option definatly gives me more flexability as to toilet placement.
 
  #6  
Old 01-24-08, 06:49 AM
M
Banned. Rule And/Or Policy Violation
Join Date: Dec 2007
Location: Chicago
Posts: 1,011
Received 0 Votes on 0 Posts
Building departments can be pretty finicky about the CI to PVC connectors they will accept, and many in my area will not pass the rubber "T" and "Y" connectors.
 
  #7  
Old 01-24-08, 07:41 AM
Terd Herder's Avatar
Member
Join Date: Jan 2008
Location: Northern Illinois
Posts: 301
Received 0 Votes on 0 Posts
Originally Posted by Michael Thomas View Post
Building departments can be pretty finicky about the CI to PVC connectors they will accept, and many in my area will not pass the rubber "T" and "Y" connectors.
Michael is right, check with the codes in your area before using connectors.

You can still get lead and oakum, but you will need a ladel, torch and caulking tools. Using friction clamps is a good idea to support it between floors. Pics would be nice.

Why are you replacing the pipe? Good luck!
 
  #8  
Old 01-24-08, 09:01 AM
M
Member
Thread Starter
Join Date: Jan 2008
Location: West of Chicago
Posts: 327
Received 0 Votes on 0 Posts
I am moving the toilet from its current location back to its orignal location (judging by the hole in the flooring right in front of the stack). They turned a bedroom into a bathroom, but created a massive, cold- as- heck bathroom w/ tons of wasted space. And deleted a bedroom in the process! So we are going back to a tiny bathroom and two bedrooms.

My stack has a tee in it, up near the flooring(in the basement). That tee has 3 elbows installed snaking around away from the toilet... I want to remove all those elbows. Now I have an empty hub (or socket) right on my stack. I want to install a PVC elbow right here for the toilet. Pics would be helpful... I'll try tonight.

I was just at Menards and found the fernco "doughnut" they advertise on their website. Fits into the hub just like oakum and lead, but its rubber and it will seal up the PVC pipe to CI hub.

It says to use soap to lube it up for installation, but I was thinking I would use RTV silicone. Lube and seal? I also plan to top the doughnut w/ the RTV. What do you all think?
 
  #9  
Old 01-24-08, 09:34 AM
Terd Herder's Avatar
Member
Join Date: Jan 2008
Location: Northern Illinois
Posts: 301
Received 0 Votes on 0 Posts
Thats also called a gasket. Check codes to see if legal. Most places only allow them underground...and use soap. In case you have to take it out, and it wont eat at the rubber. Good luck!
 
  #10  
Old 01-26-08, 08:43 AM
C
Member
Join Date: Jan 2008
Posts: 1
Received 0 Votes on 0 Posts
donut doesn't fit?

Hi I am working on a similar project. I have a ci hub I am trying to switch over to pvc. I tried the donut method with 3" and a 2" sizes. (two seperat trips to menards). The 3" was way too big, the 2" was too small, (just slid in loosly). I am pretty sure the size of the pipe on the Y outlet is 2". I don't see any mention of 2 1/2" pipe or donuts for it anywhere. So I was just thinking of giving the lead rout a try. I also read somewhere about a plastic lead replacement. What do you guys suggest? I really don't want to break into the existing 3" stack if not completly necessary. Where can I get information (and materials) on completing a lead joint?

-rob
 
  #11  
Old 01-26-08, 09:21 PM
Terd Herder's Avatar
Member
Join Date: Jan 2008
Location: Northern Illinois
Posts: 301
Received 0 Votes on 0 Posts
Pouring a lead joint is tricky...dont get burned! Dont let water get in the molten lead=burn!

Check with the library, or plumbing books. The older ones will have how to pour a joint. IMO...hire a plumber to do it! You need a torch, oakum, lead, ladle, caulking irons. Should not be more than an hours labor IMO. Good luck!
 
  #12  
Old 01-28-08, 03:50 AM
M
Member
Thread Starter
Join Date: Jan 2008
Location: West of Chicago
Posts: 327
Received 0 Votes on 0 Posts
This portion of my renov. has been slightly pushed back. But I am still planning on trying the rubber doughnut. I am connecting 4" CI hub to a 4" PVC pipe. I can't check the fit until its taken apart, unfortunatly. I figure thats its exposed, so if there is a problem down the road, I can fix it easy enuff.
 
Reply
Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: