Background:
1. Demo'd old (1962?) master bath shower (5'x3.5') down to the slab/studs.
2. Tried to get old cast iron shower trap out, but 2" drain line was so brittle that it broke off where it was inside the cast iron shower drain(see pic 2), which looks like it was leaded onto the 2".

So. I have a 2" cast iron pipe, a little jagged about 2" below the top of the poured slab. (see pic1)

I need to stick my PVC shower drain onto it.

My options:
1. If I clean up the jagged end of the 2" cast iron drain line, I can set the PVC shower drain onto it, but it will need some adhesive (I can already tell from other threads that you aren't gonna like this.

2. Glue a 2" pvc stub to the pvc shower drain, and use a no-hub 2"-2" rubber connector. But, I will need to/like to cut the 2" cast iron off about 4" below the foundation, which means making a hole big enough to get to get an angle grinder (or some other suggestion) into the hole to cut the cast iron, and also get a wrench or screwdriver and my hands on the strap clamps on the no-hub connector.

2.(b) If I have to dig out a bunch of concrete to get the new drain on, then what do you think about me digging out the entire 5'x3.5' section, and putting in a true zero threshold shower??

The trap:
I was thinking if I have to dig up concrete, then I may as well put in a new clean trap. I couldn't see down the 2" cast iron drain, so I started digging out the hair/soap/whatever chunks from the inside using a screwdriver and sucking it out with my shop-vac. The trap is about 2.5 FEET down... so I'm NOT going to replace the trap. I just kept digging and sucking until it was pretty clean and dragged the garden hose in through the window and sprayed in down the drain.

Thanks,

Thanks for the visual. It is always big help...

You can do this:

1. Get 2" No-Hub Coupling
2. Insert it over the existing 2" C.I. pipe
3. Cut 12" PVC ( or ABS ) pipe
4. Attach this 2" PVC / ABS nipple to the coupling
5. Take 2" Cast Iron "Instant Set" shower drain ( new one )
6. Separate the drain into the bottom shell and top shell
7. Slip bottom shell over this 12" PVC / ABS nipple until at the top of the concrete slab
8. Tighten 3 s.s. drain bolts ( part of the drain )
9. Take hack-saw and cut off rest of the upward sticking PVC / ABS nipple, flash with the drain
10. Now, it is ready for hot mop. Hot moper will install the upper shell for you in hot asphalt

You may have to cut of piece of the existing C.I. pipe so you have more space for the coupling and bottom of the drain. In case you don't have so much space - than purchase ABS shower drain at Home Depot. Its bottom part is much shallower than the C.I. drain. You simply glue the 2" nipple to it and proceed with hot mop.