I need to lengthen a solar blanket roller, to reuse it on a larger swimming pool. The roller is two aluminum tubes, about
4" diameter, end to end, linked by a third tube inside, ridged so that it touches the enclosing tubes at about 8 points. How to extend this telescopic tube sysem? Hammering on the inner tube (reached by a crowbar) earns me half an inch a time, but I am apprehensive about building up a burr on the aluminum, that would jam the tube permanently.Is there any useful trick to unstick telescopic tubing?