The best way to bend wood into a few partial circles , and then join them together to make a frame is through controlled application of hot water, steam and pressure. Creating this amount of hot water and pressure will require an outdoor trough or something else, that I just don't have room for.
I will probably be doing some searching on alternatives to this little problem soon. Other than the curved frame, I believe I have the rest of the door figured out, I just need to put down on paper, check my mental measurements and begin.
