The back frame will need to be at least 10' wide by 8' tall. The side frames will be the same height as the back and about 4-5 feet wide. The top frame will be whatever it takes close the 4-sided cage.
I went to a couple of hardware stores and tested the weight and strength of several types of plastic pipe, a couple of types of metal pipes, and wood rails and poles. I was surprised how well the wook compared. I had been planning on using PVC, but the wood was as strong or stronger and roughly as light and it was almost as strong as the lighter metal pipes and migh lighter than the heavier ones.
I also called a PVC manufacturer, who told me that PVC is not a good choice because of UV damage and it could be shattered by a golf ball.
I have some woodworking experience, but I could use some help with the final design. Here are the basic questions:
1. What size stock will be needed for the 10' top/bottom rails for the back frame? The only weight it will need to support is a net (probably less than 10 pounds) plus its own weight.
At the hardware store, I took a 12' piece of 1x2 or 1x3, put one end on a counter, and pushed down in the middle. It seemed strong enough. I did the same with a pole about 1" in diameter. It also seemed strong enough. I am inclined to use the 1x3, rather than the pole, because I think it will be easier to join.
I want to avoid using any additional vertical rails in the back frame. This is where the balls will hit and the net needs to be free of anything hard, which would make it wear out much faster.
2. The whole thing needs to come apart for long-term storage. If this can be done without the need for tools, that would be a plus. If not, then just a screwdriver or a wrench. What type of joinery can I use at the corners that would be strong enough and still coem apart easily?
One thought I had was a rabbet joint secured by a couple of wing nuts. I'd cut a dado half way into the end of each rail the width of the rail. They'd overlap at a right angle. Two wing nuts should hold them. If it is too wobbly, I could add diagonal pieces at each corner also secured by wing nuts.
3. The unit needs to fold flat for short-term storage, such as leaning up against the house or the side of the garage.
The sides could fold in against the back. The top could fold back or forward or be removeable.
I can use a couple of standard door/gate hinges for the sides, but they would require a screw driver to disassemble for long-term storage. Is there some type of hinge that doesn't require tools to disassemble? Would the pin-type hinge used on inside doors work?
4. It would be better if the longer rails could come apart or fold up. It would be a lot easier to store a 5-foot bundle than a 10-foot bundle. What's the best way to do that?
One idea I had was a metal plate across the cut with wing nuts to secure it to both rails. I guess I'd need a plate on both sides.
Another thought was a hinge on the bottom edge on the rail.
I'd appreciate any comments or suggestions.