Quite often we are confronted with the task of cutting a PVC pipe in a tight spot that is not accessible with an ordinary saw. Most hardware stores now carry flexible wire saws for this job, but they run in the order of $10 to $20 and are usually not at hand when we need one.
A simple solution is to use a lenght of ordinary Nylon Masons Twine. Begin by cutting a slight groove in the pipe with your saw to mark where the cut will be, then wrap a lenght of masons twine around the pipe, attach any suitable object to form a handle (Piece of wood, copper or PVC pipe, screwdriver, etc.) Then rapidly see saw the string back and forth. It will cut the pipe nearly as fast as a hacksaw. When the cut is started good, cross the ends over themselves as illustrated and continue cutting. You will end up with a perfectly straight and smooth cut in short order.
The trick is to keep it moving quickly as the friction of the twine against the pipe generates heat. As it gets hot some of the bits of the PVC will stick on the string making the suface rough as if it were forming its own saw teeth. If you stop, the hot PVC will stick to the string and cause the string to stick in place.
I commonly use this method when reworking drain pipes and have successfully used it to cut pipes up to 6" diameter. When cutting pipes of 3" or larger you will probably break the string at least once, but given that a 500' roll of the twine is $2 that should not prove to be a problem.
A simple solution is to use a lenght of ordinary Nylon Masons Twine. Begin by cutting a slight groove in the pipe with your saw to mark where the cut will be, then wrap a lenght of masons twine around the pipe, attach any suitable object to form a handle (Piece of wood, copper or PVC pipe, screwdriver, etc.) Then rapidly see saw the string back and forth. It will cut the pipe nearly as fast as a hacksaw. When the cut is started good, cross the ends over themselves as illustrated and continue cutting. You will end up with a perfectly straight and smooth cut in short order.
The trick is to keep it moving quickly as the friction of the twine against the pipe generates heat. As it gets hot some of the bits of the PVC will stick on the string making the suface rough as if it were forming its own saw teeth. If you stop, the hot PVC will stick to the string and cause the string to stick in place.
I commonly use this method when reworking drain pipes and have successfully used it to cut pipes up to 6" diameter. When cutting pipes of 3" or larger you will probably break the string at least once, but given that a 500' roll of the twine is $2 that should not prove to be a problem.