You need to start with a few sheets of paper before you start cutting ali sheet. Tape a sheet of paper so that 40mm of sticks above the top of the tube line, mark the edges of the paper on the tube so you have a reference point. You need to reduce the height of the section that goes around the corner by 10-15mm and cut small accute triangle shapes in the cut down section. When you can fold the paper over the corner with out it over lapping the next triangle along you have got it correct. Remember sheets of paper are a penny a sheet, ali on the other hand is not. Don't be tempted to use a bare hammer to bend the ali over as you'll just end up with unsightly dents, use a length of pine as a dolly and work it over in 3-5deg bents back and forth untill the job is done.
|