I am getting ready to make my immersion wort chiller. I have 50 ft of 3/8 tubing and a tubing bender (not a spring bender). I want this to look good, and I know you only get one chance when working with tubing. My question is, how do you get the tubing riser from the bottom of the coil to go up INSIDE the finished coil? The only way I can figure is to wrap the coil around a ridgid cardboard tube with a notch cut out at the bottom so that the vertical riser goes up inside the tube, then you wrap the tubing around the tube. I'm sure if I looked long enough I could find an 8-10 inch cardboard tube, or maybe a short piece of plastic drain piping would work. Any ideas?