Tube bending

Can anyone elaborate on pvc tube bending ? I'm thinking going heat gun way, but the question is how to bend without deforming cross-section of the tube ?

I have certain design in my mind that asks for tight 90deg turns...

Ideas ?

#EDIT1# Design is purely esthetic, no functional purpose, besides obvious...

I'm sure some grades of PVC tubing are bendable without heat, you'd just need the correct size pipe benders.

If going the custom bent solid pipe route i'd seriously look at using copper/stainless steel piping, when done correctly it looks superb.

No, i mean traditional flex tubes, but only laid in tight 90deg turns...
(aren't clear tubing pvc ?)

PVC is a very general term there's thousands of different kinds, its like saying I want to use metal.

If you want perfect 90 angles with flex tubing the spring method would be the best bet. Thicker tubes eg between ID and OD would hold their shape better and reduce kinking.

If you can get hold of some memory plastic tubing that would be the best for staying in shape but its not as flexible.

Could you create some form of brace on the tube to create your desired angles? If using coloured tubing you could fit a metal brace to the back of the tube to hold shape whilst hiding it from view.