How do you intend to form the case using heat?
Im asking this as Im a mech fitter/fabricator.A method to obtain sharp bends would be:
Obtain a fluorescent light fitting to the width of your intended case,bosh the glass to reveal the filiment,that is now your heat source.
Clamp the light fitting to a work mate/bench and use a piece of steel to cover half of the fitting,looking from the top the steel and filiment should be in line,for a bigger radius move the steel to expose more filiment.
Warning this gets hot + live.
Do not scribe the material as it will split and do not allow the steel to warm up.
Have a practice with a few offcuts.