What would be a good, long term product to fill the 1/4"-1/2" gap between the 4" PVC pipe I just installed and the inside rim of the cast iron bell at the stack? Here's what the deal is: I used a Fernco 4" to 4" ring and tapped that in as far as it would go. I also tapped the 4" PVC pipe in as far as it would go. Because the 4" PVC will not actually go into the inside diameter of the inside of the cast iron bell it sits face to face with it, but not perfectly. The bottom gap is exaggerated a bit since I had to slope the pipe in a bit for drainage. This does 2 things, it increases the gap at the bottom and increases the ledge fron the bottom of the cast iron creating a perfect place for water and waste to sit and pool. I am feaful that over time this will start to ooze out the bottom under the PVC pipe and past the rubber gasket. I ran some water in and it does indeed pool there. Not sure what to do, if anything. I want to be confident ptior to gluing everything up.

So, can I use a silicone caulk or some other product to fill and bridge this gap effectively or will it eventually fill itself over time from waste and use?

Thanks.

I'm not following you. Why doesn't the 4 inch pipe fit into the 4 inch fernco?? Or do I have that wrong? Sometimes (if it really all is 4 inch) you've got to file/sand the edge of the pvc pipe a little and then grease it to get it to fit in the adapter if it is one of those gaskets that fits in the bell of a pipe.

Tom

Quote:

---

Originally Posted by nervous

What would be a good, long term product to fill the 1/4"-1/2" gap between the 4" PVC pipe I just installed and the inside rim of the cast iron bell at the stack? Here's what the deal is: I used a Fernco 4" to 4" ring and tapped that in as far as it would go. I also tapped the 4" PVC pipe in as far as it would go. Due to the fact that the 4" PVC will not actually go into the inside diameter of the inside of the cast iron bell it sits face to face with it, but not perfectly. The bottom gap is exaggerated a bit since I had to slope the pipe in a bit for drainage. This does 2 things, it increases the gap at the bottom and increases the ledge fron the bottom of the cast iron creating a perfect place for water and waste to sit and pool. I am feaful that over time this will start to ooze out the bottom under the PVC pipe and past the rubber gasket. I ran some water in and it does indeed pool there. Not sure what to do, if anything. I want to be confident ptior to gluing everything up.

So, can I use a silicone caulk or some other product to fill and bridge this gap effectively or will it eventually fill itself over time from waste and use?

Thanks.

---

I don't quite understand why you couldn't get a Fernco rubber gasket to work but there are still several ways to connect PVC to cast iron. You can yarn and pour a lead and okum joint or if you don't wish to use melted lead you may yarn in okum and then caulk in "shreded lead",(lead wool) to secure it.