"MiamiCuse" wrote in message
...
I need to cut a 3" cast iron vent pipe to tie to a new PVC vent.

I am using a Milwaukee sawzall with a metal blade and it kept skidding and
wouldn't start the cut at the right place. I then used a 4-1/2" angle
grinder with a metal blade and cut a little notch and now I can engage
with the sawzall without skidding.

However after 15 minutes of cut I don't think I am making a significant
dent at all.

I used the same sawzall and cut through copper and EMT electrical conduits
like knife through butter. But this CI pipe I am not making any progress.

I can't use the angle grinder there is simply not enough room around it.

I went to HD and they recommended a "grit iron" blade. Got that and it
seems to cut a little bit, but again after 15 minutes, I am not even 10%
through the pipe. The way I am going it would take 10 hours.


Some pipe is just tougher than others. I have cut through many of them
using a 6tpi Lennox blade that I buy at the plumbing supply store with no
problems. Cutting a well baked vent stack in an attic this past summer I
even broke down and bought a Lennox diamond dust blade which eventually cut
through it. It was still a long process.

Keeping the blade lubed with a water mist from a spray bottle helped. It
still took a long darn time.

Colbyt