How to cut large diameter plastic pipe
Cutting plastic pipe, especially large diameters, can often result in a crooked cut. This then has a knock on effect of having to shave down the end to make it flat which then changes the length of pipe originally cut. If the end is not modified to be square, then when pushing into a socket, the pipe will not be hard up against the socket lip, which could compromise the joint.
Most fixed blade machines such as circular chop saws and band/hacksaws will only cut up to 4 or 6 inches, so how do we cut a large pipe? There are two options:
- Handsaw - Using a handsaw for diameters of over 160mm or 6 inch can be pretty tiring, especially if the pipe is a high pressure rating, which will result in a thicker wall, and more cutting required. This is definitely a two man (sorry..."person"!) job, as the pipe needs to be supported and stabilised properly to get an efficient cut. Even when the pipe os marked all teh way round, it is still very easy to end up with a crooked cut.
- Jigsaw - This is my preferred option, and I have used it on all manner of plastic pipe materials and sizes up to 500mm. To cut with a jigsaw you will need a decent jigsaw with a medium wood cutting blade attached, a marker pen or china marker pencil and a strip of thick flexible plastic (the kind of clear stuff that you get hanging in strips to form doorways in cold stores, factories etc. is ideal).
- Wrap the strip around the pipe and mark the pipe all the way round.
- Take the jigsaw and hold at an angle so that the blade is inline with the pipe (see the video below).
- Start cutting slowly, putting a small amount of pressure on the blade, Once the blade cuts through, it is then a case of just cutting round the pipe, ensuring you keep the blade at right angles to the pipe. Don't be tempted to "push" the blade too hard as this will cause it to cut at an angle. Jigsaws are best when they are allowed to go at their own speed.
Cutting pipe using a jigsaw, especially starting the cut, takes a little practice, but once you have it, I guarantee you will cut like this for the rest of your life :)