Help joining soil pipe

[TriggerSlab]

Hi all. My scaffolders pulled off a section of the iron soil stack. In fairness it was in poor condition. I've just been up the ladder to have a look. There's a short section that joins at the 'Y'. I thought it was all cast iron, but looking closer it's quite badly dented, so it may be hard to cut back to a section that's properly circular. It feels metallic when I tap it. The pipe appears to be a single piece (no joins) that does a 90 degrees in to the wall. I'd prefer not to replace the through-wall bit. Questions:
- what's it made of?
- can I cut it with an angle grinder, which was the original plan?
Appreciate any thoughts and comments.

ETA: To clarify: original plan was to replace Y with a plastic Y, add a small section of new pipe, and new plastic pipe above and below, joining to better condition cast iron pipe lower down.

 

[CBW]

Judging by the rust appearance, I’d say it’s cast iron. The branch off could be cast iron or lead. Scrape the paint off it, see what colour it is underneath.

 

[TriggerSlab]

Thanks - I'm fairly certain the branch off is lead judging by the dents/deformations that you wouldn't get in cast iron. I'd only ever seen cast iron and plastic ones, so it threw me a bit. What's the best way to join it to a new plastic Y? I've bought some push-fit slip couplings and the rubber sleeves with the big jubilee clips. Any good?

 

[CBW]

You might be able to use a dc1 but might not get the lead in, so probably best with the flexseal with jubilee clips.

 

[Exedon]

That is a lead bend it will almost certainly brass section soldered to it where it fits into junction,
The lead will be easy to re round proper tool was called a plumbers dummy (still got some somewhere) but you can make do with a hammer shaft or similar
Once you have it back to round be much easier to join.
If you need to shorten it old hand saw works well.

 

[TriggerSlab]

Thanks. You folks are great. You've pointed me in the right direction. Just what I needed to know.