First time cutting cast iron stack! Advice please!

[Fireboy24]

Hi there,
Have to cut into cast iron stack tomorrow to connect toilet tee. Can't replace everything above it in plastic so need to use a fernco coupling on the top cut. Was wondering if instead of doing the same on the bottom cut you can just pull the male part of the cast iron pipe up (it's a vertical pipe) out of the female coupling. Is there a upvc male connector that will go into the cast iron female connector?? Any help/guidance would be hugely appreciated! I've attached a pic of an external stack (not the one I'm working on to show the type of connections I'm working with.
also just as an aside I've gone way over the top bracketing the top and bottom of the cast iron pipe that's staying so I don't have to worry about it moving etc while I'm replacing the middle bit!

thanks in advance

p.s have bought a snap cutter. Anyone with a lot of experience cutting cast iron recommend that or angle grinder with new metal blade???!

http://www.google.co.uk/imgres?imgu...dgfgN&tbm=isch&client=safari&ved=0CEUQMygNMA0

 

[stevetheplumber]

snap cutter realy only work well on new cast and spun drain i would go with the angle grinder youll probally have to cut a window to get right throughcut the line you want as far as you can then cut again six inches up then cut down each side so you remove the front this will allow the head of the grinder to go inside the stack to cut the back
i wouldnt bother trying to get a pipe out of a joint you need a lot of heat and will ruin a good screwdriver trying to get the lead and yarn out

 

[TBServices]

Why can't you replace the top half of the stack?

 

[kirkgas]

If it's fitted properly, and being cast and old, it will probably be fitted properly it is almost impossible for you to pull it up and out the female socket, it will have a rope a lead run joint, or a rope and cement joint, either way it will be solid, I would use a timesaver branch for this and would cut it twice with a grinder, don't know fernco but I assume it's the same as timesaver, ie rubber seal with split cast outers which allow a branch to be fitted in to a fixed line,
It is possible to break the cast out of the female socket, but you need a bit of room to get in with a hammer and chisel, and you need to force a bag or something into the pipe further down than the socket so that you can vertically split the pipe inside the socket without the chunks dropping down, vertically cut down then about an inch or so further away cut down again then the rest of it will snap in on itself (that's why the bag is there, I only break the bit out the socket if I'm renewing a bigger section as it's a hassle, far easier to use the timesaver branch and with clamp either side