Those were helpful links.
Applying heat gun to the side was advised (I was thinking of trying to blow the hot air THROUGH the pipe).
I like the idea of packing it with sand to prevent kinks. I think I would try to confine the sand to the 'bend area' with some kind of tampers with loose-fitting plugs.
I thought I might have to build a box of bricks around it to hold the heat in - guess not!