Tom, how you doing? Hope you had a great newyears. Now for my question. My main stand pipe that I will have to tie into is 4 in. cast. The present drainage comes off of the cast at what looks like a 4 in. sanitary T. My present drain that ties into the cast is run out of 3 in. copper. Is it possible to connect my new pvc drain line to the 3 in. copper? If so how is this done and what do I use? Or do I have to tie directly into the cast stand pipe, or do I just need to replace all the cast? This is all taking place on an upstairs bath. The 4 in. cast main line runs from my basement up through the roof of the house, aprox. 40 ft. in length. I really dont want to disturb this line if at all possible. Thanks again Tom. Dave

speedball1

Good morning Dave, Absolutely yes! To tie the two together takes a threaded connection. First solder a 3" male threaded adaptor on to the copper line. You may then teflon tape the threads and connect a 3" PVC female adptor to the copper line. You have converted from copper to PVC and after you prime the PVC you can make your glue joint. My holiday was great. Thanks for asking. Tom

DDave

Tom, thanks for the info. Your coments for the conection of pvc to copper mentions the use of the primer. Do you have to use the primer with the multy purpose glue? direction on can say only to use a cleaner and then glue the joints, which is what I have been doing so far. Was that a big WOOPS or am I ok? Dave

speedball1

PVC primer and cleaner are the same things. The purpose of primer/cleaner is to take the glaze off the PVC and give the glue a chance to take over. If you find youself out of cleaner you may use plumbers sand cloth or steel wool to remover the glaze from the PVC joint. You're doing fine. Regards, Tom

DDave

Thanks Tom! I starting to feel like I owe you a steak dinner! Dave