I need to a cut a 4" cast iron sewer line and am wondering whether to
use a rental chain type cutter or buy those treated sawzall blade ?
Of course using cutoff wheel would be great if I didn't have to worry
about potential explosion from sewer gas .
a Milwaukee "AXE" blade on a sawzall will cut through cast iron pipe like
it will even cut through a cast iron tub..............3 blades and 2 hours
but the chain is always the easiest and fastest way (providing you have the
room to wrap the chain around the pipe).
I just made 2 cuts thru 4" cast iron soil pipe and 2 thru 2". I used a 4"
Makita side arm grinder on recommendation of a couple of plumbers. I was
surprised at how quickly it went. Started with a used cheap wheel and pretty
well used it up in the process. I tried a DeWalt Recip. saw with a new
hacksaw blade first and it just made a shinny place on the pipe.
I too, did this recently. I needed to move a toilet flange a
few inches to the right. I could use an offset flange which
gives you 2", however, the original flange and pipe was cast
iron in a concrete floor. I used a 3" abrasive wheel on a 6"
extender mounted in a router. I used a variac to keep the
router running at a slower speed so it wouldn't bend the
extension shaft due to small unbalances in the wheel and the
extension. Taking is slowly, I was able to make a clean cut
about 5" below the floor level. It really didn't take all that
long, maybe 10 or 15 minutes. I was then able to mount the
offset flange with appropriate iron to plastic conversion
hardware. Big job for only 2", but it was necessary for the
My inuition is warniing me about a potential fire or explosion from
the sewer gas ( methane & H2S ) if using a high speed spark
generating abrasive wheel on a circular saw or angle grinder . I
wonder if it is something to worry about .
On Wed, 28 Jan 2004 00:05:11 GMT, "rb608"
Oops, I forgot to mention, when I did it, I made a "plug" from a
bunch of plastic grocery bags. I tied a string around the
bundle and pushed it into the pipe. Did the cutting, and then
pulled out the "plug." This also prevented me from smelling the
I did it with a hacksaw because I don't own an electric. It was a lot of
work and it takes two blades for the two cuts I made to remove a section. I
don't recall if I was using the better grade blades or not.
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