Metal waste's

[nickelarsed]

Hello all,
Been doing some contracting work just ripping out bathrooms and putting in new for the council. Most of them still have the old copper waste pipes which go into the stack using a nut and olive. Now usually I can just connect my plastic pipe on to the metal pipe with a compression fitting, but the other day the old waste was so soft (full of flux for about thirty years) that I had to replace the whole length of pipe. Realised I have no idea how I would connect plastic pipe to an old metal stack. In the end I found a bit of scrap from the van which was in good nick and just replaced it. But is there a special fitting or method to fit plastic to an old stack? It's just one of those things that's never come up before. Thanks.

 

[PlumbBobBob]

probably a strap on boss? like this

 

[scotty plumber]

You cannot connect that to a cast stack

 

[nickelarsed]

Maybe I'm being daft but that needs to be solvent welded? These metal ones have a thread sticking out of them where the nut screws onto so I don't think I can fit a boss anyway. Thanks though

 

[scotty plumber]

The only way i can think of doing it is to cut the copper waste as close to stack as possible and connect in to it using a mc alpine coupling and re-run in 40mm plastic

 

[mountainman]

Take the old copper to iron fitting out of the CI boss and replace it with a plastic to iron fitting.
Job done!

 

[nickelarsed]

That was pretty much the way I've been going Scotty, just nearly got snookered the other day. If I hadn't had a bit in the scrap bin (gotta love these old flats) then no idea how I would have fixed it. Wondered if there was some special adaptor. Thanks for the reply

 

[nickelarsed]

Nice one mountainman so there is an adaptor. Something I'd find in a mcalpine book? Does it have a specific name?

 

[Mike Jackson]

Just ask for a 1 1/2" MI or 1 1/4" MI by solvent weld fitting. Most merchants will have them in stock.

 

[nickelarsed]

Thanks mike