To give an object thickness you use the extrude command mate. Go to editmesh>extrude and the manipulator will pop up...then grab probably the 'y' arrow and move it towards the centre this should work and you will see it getting thickiness.
Interesting pipe mate...can I ask what it is for??
cheers bullet
bullet1968
"A Darkness at Sethanon", a book I aspire to model some of the charcters and scenes