Fabricated from 25 feet of 5/8 inch copper refrigeration tubing with 3/8 copper tubing on the inside. I don't remember the exact name for the elbows, but they have an extra tapped hole in them. I picked them up at Home Depot.
The tapped hole was then drilled out so that the 3/8" ID tubing would slide through it.
I used 5/8" tubing for the cold water because it was donated by Bill. Notice the foam insulation still in place. I couldn't find 5/8" fittings so I had to make a bushings and use 3/4" elbows. I recommend that you use 3/4" copper tubing if you have to purchase it.
Getting the 3/8" tubing inside the 5/8" seemed impossible. I uncoiled both pieces and laid them as straight as possible. Then I tried to slide one into the other. No such luck!
After about an hour I learned the trick. Hold the 3/8 firm in one hand, slide it into the 5/8" until it jams. Now rotate the 5/8" while keeping the 3/8" from turning all the while still applying pressure to the 3/8" tubing. It took about five minutes to get all 25 feet inserted after learning the technique. I then used a half barrel keg as a coil form to wrap the tubing around.
Remember the cold water goes in the side that the chilled wort exits. Works like a charm.
After use I flush it with 180 degree water from the liquor tun. When I'm ready to brew I boil water in the boiler and run it through for about fifteen minutes. No infections yet! Knock on wood.