How to Temporarily Join 3/4″ and 1″ PVC poles.
PVC pipe can be easily cut to make poles and frames to support banners. However, it’s not very convenient to carry a long piece of pipe in the car or even down a crowded sidewalk. Here is a simple way of joining two pieces. It takes advantage of the fact that the outer diameter of 3/4 inch pipe is one inch, which is the nominal inner diameter of 1 inch pipe. Actually they don’t easily fit and come apart again without this simple modification. But, if you cut a five inch slot in the smaller pipe (as shown above) it’s easy to fit them together and once the pipe is fully inserted they fit tight and won’t easily slip apart.
Study these pictures for fabrication details and review the notes at the end for helpful hints.
In the picture above notice that I drilled two quarter-inch holes about 3/4 inch apart and made a hacksaw cut to connect them. This cut forms a “T” with the five inch slot cut from the open end. The long slot allows the smaller pipe to collapse enough to slide inside the larger pipe. The short transverse cut relieves stresses on the plastic to prevent cracking with repeated flexing.
You will find that when the pipe is inserted past the end of the long slot it begins to bind and hold securely. You may want to put a thin film of candle wax or silicone grease on the overlapping parts to make them easier to take apart later on.
When PVC pipe is assembled in this way the union is actually stronger than either piece of pipe alone. It’s also more secure than using the couplings one would attach for plumbing joints. You can make just about any length of pole you want by alternating sections of 1″ and 3/4″ pipe.
Note that PVC pipe is not rigid, so long pieces sag unless supported along their length. I’ve used poles made this way to support a small Wi-Fi antenna for my RV and to make a light-weight pole for a horizontal banner to be carried in a march.