Cutting cast iron - is it difficult?

[IPDQKWID]

In order to get a pressure test done on an addition (two bath, laundry), I need to seal the drain piping, and this location seems to be the least disruptive. How difficult is it to cut cast iron? Would a rented soil pipe cutter be up to the job? Should I buy one?
I intend to replace this cast iron (installed some time around the last ice age, I'm sure) with PVC.
Thank you

 

[IPDQKWID]

I see in the 'similar threads' below a number of threads with the info I was seeking. Got my questions answered. The search tool didn't reveal these as easily. Snap cutter it is.

 

[Sponsor]

 

[Jeff H Young]

I don't even own snap cutter I have in past but long gone you might rent . I've borrowed, I've busted it with hammer and then cut smooth with a grinder, used a skill saw with proper blade, chop saw (not in place) , saws all with a metal blade, (they have far better blades for cutting cast iron. I've never used 10 20 bucks each I don't know but readily available. So there are a few ways to cut it.

 

[Terry]

I have used the Diablo Steel Demon's on cast and they work really well with a sawzall.
Always use eye protection when cutting.

 

[IPDQKWID]

Close to getting the DWV piping air tested. I cut out a 10" section of that cast, and put Fernco's over the cut ends. I torqued them to the required torques - should I have tried to make sure they were smooth? Is it likely that air will be leaking there?

I have a gauge and Schrader valve contraption put together, and I load the system up to 5psi, and around 7 minutes in I can see it falling. At the 15 minute mark it is down to 4psi. I need 15 minutes to pass. Some soap water at one of the cleanout plugs was bubbling ever so subtly, and I could hear it, so I taped and doped those plugs threads, and torqued her back in (not sure it was wise to dope a cleanout plug), re-loaded and same thing, drops to 4 by the 15 minute mark.
I've soaped the valve/gauge contraption (which is heavily doped) and I see no bubbles anywhere.
If I go back to the cast iron and try to beef up the seal, is there anything else I can do (like if it was threaded pipe, I'd add dope)?
Thank you for any advice - I have around 85 pipe joints on this plumbing, and I've gone to around 60 of them with soap-water and other than that cleanout plug, no leaks detected. I'm thinking the cast iron with the Fernco covering it is where it is leaking, and this is driving me nuts.

 

[IPDQKWID]

This is the cut out section of cast iron. Would you expect a Fernco Kwik-Cap torqued to 60 in-lbs to seal this pipe for an air test?

 

[Tuttles Revenge]

If you suspect the test fitting has some rough edges.. get some Hercules Griip and lightly lightly coat the inside of the band and the outside face of the pipe, wipe off any excess, let it tack up for 5-10 min then put it back together. Wear gloves and clothes you don't mind being ruined by a messy adhesive.

A soapy solution from a spray bottle will show leaks too like you would do on a threaded steel gas system.

 

[DIYorBust]

I've cut cast iron with the diablo and with the snap cutter. Neither is great fun in a small space. The snap cutter tool is too expensive for me to justify owning unless I had a real lot of cast iron to install, it can be rented.

But I'd personally hesitate to use it on really old pipe like that. If you damage that tee, or break the pipe off inside you're in for some major extra work. I'd feel more confident using the sawzall here. It takes longer, but you're really just doing one or two cuts.

One tool I asked about here a few months back is the this toledo hinged 4 wheel cutter. https://toledo-tools.com/toledo-pip...ed-pipe-cutter-fits-ridgidr-reedr-wheels.html With the correct wheels it says it can cut cast iron. The tool is much cheaper than a snap cutter, and probably makes cleaner cuts than either the sawzall or snap cutter, and I'd certainly prefer working with it in a small crawlspace over the other two options. But I never did try it. If you do keep us posted.

 

[Jeff H Young]

DIYor bust, I wouldn't consider that tool , don't think it would work very good on cast iron. ratchet snaps or a good saws all blade, grinder, or chop saw (not for position cuts)

 

[WorthFlorida]

Might be possible to use a test ball. Easier than cutting up a CI pipe.

https://www.amazon.com/Cherne-27004...ocphy=9053092&hvtargid=pla-310329660395&psc=1

 

[IPDQKWID]

Thanks for the ideas guys - I soaped the hell out of the cast iron Fernco cap, and it did not show leakage. I had my misophonic son (he hears things others cannot - not to worry, its not voices), and with all sound shut off, system loaded up with 5psi, he walked around the addition, and comes and gets me 10 min later, says he hears some 'crackling' in that set of pipes up there. Sure as shit, on the backside of one of the joints (10ft in the air), soap-water spray (Thanks Tuttle) was producing a bubble every 5 seconds. I missed that twice because I didn't wait long enough.
Currently putting on a repair coupling, and if successful, getting my air test signed off Tuesday.

 

[Casman]

I’d used a snap cutter 20 years ago during last remodel. Didn’t care for it one bit. This remodel I used 2 other methods. Both the sawzall and a 4 1/2 angle grinder with a diamond blade. Both worked equally well for the cut and each took less then 2 minutes.