Mark; good point about posting building tips. It happens that I just got back from the hardware store, where I was looking for an elbow for 1/4" OD nylon tubing for the pitot/static system in my Air Camper. I had it in my mind to get the standard brass compression type of fitting, but I noticed some plastic push-on fittings with a quick-release feature for a couple of bucks less. For very low pressure applications like this (NOT for fuel or brake lines), these fittings are far easier to work with than the brass ones. The package says the fittings can also be used on soft copper or aluminum OD tubing.
I'm not sure that I would use the push-on fittings for softer flexible plastic tubing, but for the stiff nylaflow tubing, they work great. The part I got is like this one: http://www.amazon.com/Watts-PL-3002-Push-Elbow-4-Inch/dp/B000BVMZ9M Oscar Zuniga Medford, OR
