Flexable Tube

Probably extrusion molded. It comes out of a "die" into a coolant tank which instantly hardens it.
Regards, Joe Agro, Jr. V8013

If it is an extrusion mold how does the spiral rib end up on it, so it can be bent and not kink?
Terry

I misread the original post. I thought he was referring to plastic tube used for runs where metal is not needed. Now that I go back and re-read it, I asume he means the metal shielded "bendable" tube that holds it's shape a bit.
I've never looked closely at those, but I assume they are metal on teh outside and something impervious on the inside? Or... Are they /\/\/\/\/\/\/ walled?
If they are /\/\/\/\/\/\/\ walled, tehy could be extruded by a die that moves in and out while the material is put into a cooling off bath or it is done post extrusion by some sort of crimping machine.
All pure guesses of course...
Now... If you want to talk about polytube, I can talk a little from experience.
Regards, Joe Agro, Jr. V8013

I have used the much bigger and much higher pressure flex tubing (used for rocket fuel and high (3000 psi) pressure gas). It is obviously corregated (not spiral) and welded on one side and encased in braid to hold the pressure and mechanically protect it.
If the plumbing pipe is spiral I might guess a rotating extrusion nozzle.