Okay so finally got the collars and the bar is complete. I like the way it turned out - perfect for home gym use. I'm in the process of making some for a couple of local boxes but instead of tape found a reasonable source for galvanized pipe. Will be much better from a maintenance standpoint. The tape on the part of the bar where you load weights is pretty nice though to make up for the smaller diameter of the pipe (1.9"). The bumper plates fit more snugly (but not tight) and you can use standard sized collars to hold the plates on.
This one is 6' so in between the 5' and 7' I will make for the boxes. Too much waste at 6' (standard pipe length is 21'). I will make a 4.5' with the length I have leftover I'll have my daughter use it... :)