Cutting cast-iron soil pipe

[Ben Edgington]

In order to install a new close-coupled WC I need to shorten the existing soil-pipe by a few inches. It appears to be cast-iron (1950s).

My Collins DIY manual suggests hiring a "ratchet chain-link cutter" for this task. I seem to recall reports, however, that cast-iron can be sucessfully cut with an angle-grinder.

I have sufficient access all round for my 4.5" grinder. What are the chances of managing this, or is there a significant danger of breaking the pipe? Would regular metal-cutting discs do the job?

Thanks for your thoughts.

[robgraham]

Unless you are very hamfisted I doubt if you would break the pipe and I would think a metal-cutting disc on the angle grinder would be the ideal tool. It's the one I'd use if I was doing what you're doing.

Rob Graham

[jerrybuilt]

Yes, it can, just keep the blade moving so as not to locally heat the pipe too much. Make a "ring" around the pipe first, not going right through, and gradually deepen it 'till it goes through. You could probably use a hack-saw, too.

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[<nightjar>]

I cut up a cast-iron bath with an angle grinder, so that two people could lift the bits out. It worked fine, but definitely wear a mask. For a pipe, I would wrap a piece of wide masking tape around first, to give you a line to work to. Start with a light cut to mark the place you want to cut and keep the cutter moving. Then it is only a question of time.

Colin Bignell

[Ben Edgington]

Many thanks for your advice and others who replied. I'll give it a try later this week and let you know how hamfisted I turn out to be 8^)

[Brian S Gray]

I have watched an experienced professional cut through a cast iron soild pipe 'spur' in situ with a hacksaw to shorten it. I was very impressed as he made a clean square cut but it looked very hard work I do not think he would have done it if he could have thought of any other way in the confined space available!

[Ben Edgington]

Feedback as promised...

Despite the Collins manual's insistence that *all* old soil pipes are cast-iron, and despite it's black, cold appearance, it actually turned out to be some kind of cement (painted black). The pipe walls are thick: about 10mm or so.

Wary of asbestos (there is a lot of asbestos cement around this house) I put on a high-grade mask, damped the site down with lots of water and cut not too vigorously with a hacksaw. Five minutes later, job done.

Very relieved to get new WC installed and working perfectly 8^). Bath next.

Thanks for all the advice,