Bathroom torn up and wife returning from vacation!! HELP!

[JDkimes]

In a bathroom sink drain that runs horizontal over about 15" and connects to the cast iron stack in a threaded connection.
There was a steel pipe that I'm taking out (full of corrosion and constantly plugging).
The steel pipe was 1 1/4"
Since there's no 1 1/4" ABS can I put a new ABS threaded fitting on that goes up to 1 1/2" (and then run 1 1/2" all the way back to the sink tailpiece)??
I'm concerned about the DWV necking down from 1 1/2" down to 1 1/4"

Follow up...if it's not okay to neck down, can I use PVC fittings?
(I'd prefer the ABS because another concern is the tight 90 degree turn this takes right after it goes in the wall, I'd like the sweeping 90 better)
Help wife coming home after vacation and I have the toilet and sink both in the garage)

 

[Kordts]

Get an 1-1/4" pipe x 1-1/2" hub male adapter. They make them in pvc, I would guess they come in ABS as well.

 

[Sponsor]

 

[JDkimes]

Still the problem is that I'd have a 1 1/2" going into a 1 1/4"

The cast iron threaded connection is 1 1/4, I know there's lots of adapters to hook 1 1/2" up to the 1 1/4" but then I have a bigger pipe flowing into a smaller hole. Sounds like trouble to me.

 

[Kordts]

They make 1-1/4" pvc. The lav drain is 1-1/4", so you don't need to run an 1-1/2" tubular waste. You can use 1-1/4". Or use my original idea, because, the lav drain is the same size as the stack opening.

 

[hj]

drain

You shouldn't increase the drain size, nor should you use PVC pressure fittings for a drain. Therefore, I don't know how you will do it, but a picture of what you have might give us some ideas.

 

[JDkimes]

My plan at this point is to break out (using pipe snapper) the 3x3x 1 1/4 cast iron sani-t and replace it with a no-hub sani-t 3x3x 1 1/2 (or 2") connect with steel shielded Fernco's and then run a 1 1/2" ABS drain. I don't see any other choice really.


I will use some steel strapping around the cast iron to make sure it doesn't slide down when I cut it.

Any thoughts?

 

[Jadnashua]

it might be safer if you used the clamps designed specifically to hold cast pipes...unless you have a branch you can hold, the main line would be really hard to put a strap on that would hold.

 

[Gary Swart]

CI is unbelievably heavy! You might think you had is well strapped, but one it is cut...BAM!! The whole thing can come crashing down. I say this with authority, because that's exactly what happened to me. Fortunately the build structure kept the pipe in a more or less straight line so it missed me and my helper, but it sure made a believer out of me. I'd find a 1-1/4" adaptor and use PVC and leave the CI alone.

 

[Kordts]

I would still go with a male 1-1/4" x 1-1/2" socket. You can run 1-1/2" pipe. The amount of water coming out of the 1-1/4" drain won't be magically multiplied by draining thru a couple feet of 1-1/2" pvc. You are making a mountain out of a molehill.

 

[JDkimes]

You may have been right about making mountain out of molehill but just didn't seem right to me.
In the end I bought some of the real CI clamps, dug through the insulation and put them in holding the CI secure and then cut the CI san-tee and put in an ABS sani-t using steel shielded Fernco's to tie in the ABS sani-tand and went w/ 1 1/2 on over the 20 inches at 1/4"/foot, sweeping 90 out of the wall and I'm set.
Tested it with a funnel, a hose and some pitcher of water (not a real pressure test but...) hopefully it's all good.
It's all closed up behind the drywall now.

I got a cast iron 3x3x2 san-t but because of where I had to cut it was too short.
Does it sound right.
Thanks for the advice.

 

[Mikey]

That was a lot of work; hope it continues to be watertight for you. I think Kordts had the right idea, tough. The only reason to worry about a size reduction in a waste line is it will increase the chances of a clog. However, if you're just draining a lavatory, there's almost zero probability of anything going down the drain that will cause such a clog. In the worst case, you're only 15" from the joint, so by taking the trap apart you could look down the 1 1/2" pipe and clean out any clogs with a bent coat hanger.

 

[JDkimes]

Actually that's the reason I was doing this in the first place.
It was clogging so much w/ my wife and two daughters and long hair I had to snake it out at least twice a year. I was tired of it.
I'm remodeling the bathroom and had the vanity and toilet out so wanted to take the opportunity to fix it and wanted to avoid any clogs.

I don't think there's reason to think it will leak. But I guess that's a chance. Was there something I did that would lead to one?