i am also a pipefitter and tubeing & instrument fitter. from my experance you can get a good idea of how it's done from a book but ( BIG BUT ) you will have to bend alot of tubeing to get good at it. there are many trick's to the trade that take time to learn. you must measure correctly to start with, you will have to consider the take-out of fitting's used. if lines are to be run side-by-side you must plan your bend's and add or subtract the o.d. of each line ( if lines are touching each other ).alway start at one end of line and never reverse the bender unless you have to. alway's use the center to center measure to make your bends. use a speed square to check your bends and adjust as needed, you will have to go past the marks on the bender ( a little )as the tube will tend to spring back a little. some things are only learned by hands on experance! bend a coat hanger like you need the tube and look at it before you make each bend. use a sharpie marker to mark where you need line up the bender on the tube. here is the easy way to do it .....example...two bend's with center of bends 12" apart in a run of tubing...mark a tube with the sharpie where where you want the first bend,place tube in bender with sharpie mark at the the two zero's on bender lined up, bend your 90 , next measure from center of that bend and place a mark at 12" and line that mark up with the 0 dagree line again and bend another 90. you can do this also on 45's. this way you do not have to add or subtract for the radius of of the bend. do not reverse the bender when you do it this way. aint it easy.
edit..the bender in the above photo has an L where on some benders there would be a 90, just depends on the brand of bender.
Last edited by fodman on Sun Dec 04, 2011 1:56 pm, edited 1 time in total.