tghhs wrote:Also i belive them to be safer and on a first build easier and cheaper
Cheaper, perhaps. Definetly
not safer.
1. Standard pressure rated PVC pipe has a heck of a lot bigger safety margin.
2. PVC is much more tolerant of its "history" than is a PET bottle. If you've flexed or crushed the bottle you have significantly lowered it's failure pressure.
3. Epoxy can be used safely to hold things together,
if you know what you are doing and are careful.
In the long run, properly glued PVC is going to be almost as cheap and, more importantly, a heck of a lot safer.