Hi all,copper pipe cant be used for brake pipe, it work hardens,it must be annealed after two years of use or it will crack/fracture. It is illegal to use as brake pipe in North America , I would suspect the law is the same in the U/K. What we do use is a special galvanized pipe that has a copper lining to prevent internal corrosion, I make new pipes most every day from this pipe for vintage jags,MG,s & triumphs. The tool we use for flaring the pipe ends is a Picavant tool from U/K it is high quality but expensive,it has dies to fit all the different flare pipe diameters, it is for sale on their web site. Now it will be O/K to use as a cooling jacket on a electric motor.pack it with sand & wrap it around something slightly smaller than the motor, it will do the job no problem. Mick B.