Ralph, the Poly glue is waterproof (I use it on outdoor furniture), but it does have pores in the structure - if it isn't clamped right, or the joint is bad, it forms foam, and the foam isn't as strong as the primary glue. For the turning part, I wouldn't worry about poly, but I don't know how the joint would work in a dishwasher.
Marine epoxy would probably be very good. People who have become comfortable using epoxy swear by it, and can tune the hardener/resin ratio to get various open times, etc. I am not an epoxy expert.