Of course, there are a ton of "ifs" that may change the cost and utility but if a 5 gallon keg for cheap is the goal, corny is the answer. I'm all for creative thinking and stupid DIY builds. I don't think I ever bought a ready made brewing gadget yet.
The OP was looking around in the big box store for ideas so I'd assume he'd be paying retail for these parts. OK, go asking around at construction sites for some leftover 6" stuff. Scrimp on the pressure capacity by welding on some end caps for $14 each.
Eh, every way it can be spun ends up with a poor solution to a problem already solved. Maybe he had some other requirements in mind that would change the outcome but we're just speculating now. I want to understand why a 2-3 liter PET soda bottle isn't an immediate better solution.
The OP was looking around in the big box store for ideas so I'd assume he'd be paying retail for these parts. OK, go asking around at construction sites for some leftover 6" stuff. Scrimp on the pressure capacity by welding on some end caps for $14 each.
Eh, every way it can be spun ends up with a poor solution to a problem already solved. Maybe he had some other requirements in mind that would change the outcome but we're just speculating now. I want to understand why a 2-3 liter PET soda bottle isn't an immediate better solution.