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Jaxmidway · Sep 3, 2007, 12:53 PM

I am planning to replace my existing waste drain from kitchen with PVC, What is the best method for cutting black cast pipe. I don't want to break or crack since I will be connecting with boots.
Much Appreciated
Jaxmidway

KISS · Sep 3, 2007, 01:57 PM

You can't crack it. Cut it with any method available, preferably power. A power hack saw is usually used when it was put up. A saws all is probably the best choice. So will a jig saw. Make sure you use the right blade. A surface grinder with a cutting wheel in it will work too.

Clearances when using the power tools will likely be the biggest problem. Remember to wear your safety glasses.

labman · Sep 3, 2007, 06:32 PM

You might wait and see what others have to say.

speedball1 · Sep 3, 2007, 06:46 PM

Originally Posted by Jaxmidway

I am planning to replace my existing waste drain from kitchen with PVC, What is the best method for cutting black cast pipe. I don't want to break or crack since I will be connecting with boots.
Much Appreciated
Jaxmidway

If you want to spend a lot of time and go through a slew of metal blades then take stupids advice and use a Saws-All. Cast iron is very hard and dense and cuts very slow.
To cut cast iron you use a set of snap cutters if the pipe's horizontal and a set of ratchet cutters if the pipe's vertical. If the pipe's in a trench use the ratchet cutters. You may rent the cutters at your local Rent-All place. If the drain line your replacing is a vertical stack don't use flexible couplings. Use a shielded coupling,(see image) It will give you better support. Good luck, Tom

Jaxmidway · Sep 3, 2007, 07:05 PM

Speedball
I appreciate your professional advice and will check out my local rental establishment.

KISS · Sep 3, 2007, 10:14 PM

It seems like I had galvanized and cast iron confused, even though it was black. I did find this thread though which suggests that SOME plumbers prefer a saws all or grinder method with the proper blade:

Award winning plumbing, kitchen, water and bath help, discussion and advice forum = Plbg.com

I do appreciate the snap cutter method. Cool. Thanks.

labman · Sep 4, 2007, 03:51 AM

In general, in forums where we have a highly experienced member, it is better to listen to their advice than go to some web site a less experienced person finds. There is a lot of nonsense out there.

iamgrowler · Sep 4, 2007, 07:24 AM

Originally Posted by labman

In general, in forums where we have a highly experienced member, it is better to listen to their advice than go to some web site a less experienced person finds. There is a lot of nonsense out there.

Actually, the link provided by Stupid should have also been considered helpful.

Bosch, Lenox and Milwaukee (just to name a few) all make tungsten carbide blades designed specifically for cutting cast iron soil pipe.

A diamond blade in an angle grinder also does a great job of cutting cast iron soil pipe, and is very handy for knocking down the lettering (never install a shielded coupling over the raised lettering on cast iron pipe) cast into older bell and spigot cast iron soil pipe.

A snap cutter is always my first choice, but there are situations where a snap cutter causes more problems than it solves.

Cast iron piping, particularly if it's been submerged in a wet crawlspace or acidic soils can be very soft, and will just be crushed if cut with a snap cutter. There are also homes out there plumbed with service weight cast iron during WWII when iron was scarce that will shatter if tapped gently with a hammer.

Before cutting cast iron soil piping, I always tap it with a wooden mallet, if it rings like a bell, I use a snap cutter, if it gives a thunking sound, I use a sawzall with a tungsten carbide blade or a angle grinder with a diamond wheel.

Jaxmidway · Sep 4, 2007, 06:37 PM

Again thanks for all the great input... I will use the wooden mallet test. The house is in North Florida, built in the 50's and the pipe in situated in a 3' crawl space under the house. 60% of the pipe is buried in a sandy soil. It's pretty dry under there though.

speedball1 · Sep 5, 2007, 11:02 AM

If space is real tight a grinder or Saws-All is the way to go but if I can get in with a set of ratchet cutters. I live in a area where we don't run into much old cast iron so I don't test cast iron with a wooden mallet. If we riun into nasty cast iron we just replace it with PVC. Growler/ keepitstupid, all good advice. When I was out in the field all my Saws-All I had was metal cutting blades and that took a lotta time and a lotta blades to get through cast iron.
Good luck, Tom