Hey guys, I am cutting out a 4 foot section of 4" cast iron stack pipe and installing a pvc cleanout and a y section of pvc near the top. I have already installed riser clamps on top and bottom. What can I use to adapt the pvc to the cast iron? I have seen some guys say rubber donut types or with lead. The cast iron pipe is approx. 4 1/2" in diameter. Any suggestions on what to use. I have done this before on another home but a little different situation. Should I just use hub adapters? Thank you in advance , Nick

Hey guys, I am cutting out a 4 foot section of 4" cast iron stack pipe and installing a pvc cleanout and a y section of pvc near the top. I have already installed riser clamps on top and bottom. What can I use to adapt the pvc to the cast iron? I have seen some guys say rubber donut types or with lead. The cast iron pipe is approx. 4 1/2" in diameter. Any suggestions on what to use. I have done this before on another home but a little different situation. Should I just use hub adapters?? Thank you in advance , Nick
DO NOT use ruccer couplings on az vertical stack. They aren't ridged enough to support a vertical joint. Use shielded couplings,(see image) to join the PVC with the Cast iron. Good luck, Tom

Thanks for the info Tom. I'll post the results of my project when I finish. Thank You!!