Does anybody have a method for making a dome for a storage tank made out of a cardboard tube or PVC type pipe?
Certain brands of PVC end caps work great. Some are squared off, but others are dome-shaped.
Plastruct offers dished domes in various materials and diameters. I believe the smallest diameter is 2", and the largest is 6". I know that they have both acrylic and styrene versions, at a minimum.
Take thin plastic or heavy paper, cut out a circle larger than your tube, cut a straight line to the center of the circle. Overlap the 2 cuts until you get the desired height you want. Glue the overlap. I glued on strip polystyrene as ribs. The small water tower is a toilet paper roll with Japanese toothpicks glued on the outside and heavy thread for the bands. The large tower is made with 2 CD's, top and bottom with thin plastic wrapped around them to give you a perfect tube, The rest of the structure is polystyrene. The two milk tanks are 1 1/2" plastic tubing with precision board glued to each end and sanded to the shape I wanted.
Thank you all for the great suggestions...I am constructing a dairy factory and will use The methods you all described.
I use tank heads made by Plastruct. They cost a little more but they are very accurate and achieve an excellent result.