The 90 degree bends seem to be mandrel bent from the reduced diameter at the bend but to my surprise........inside the aluminum tube(not all) is a steel 1/2 " x
.050" tube inside which is a very sloppy fit. What is this about? Would it be to help the aluminum to not collapse but like I said it's looks mandrel bent. I am tearing it apart because I need the tube for my heli project. We don't use it and it's been in my junk pile for years. No.........I don't use present deck furniture for my projects.