Visit your local home improvement or plumbing store to select a diameter of piping which feels comfortable in your grip. Have the store cut the pipe to the length you wish your barre to be, anywhere from 4 to 8 feet.
Ask the supply store to also cut two pieces of pipe to the height you have determined suits your frame, minus the dimensions of the elbow and "T" joints.
Have the supply store cut four additional lengths of pipe to 1 foot each. These will act as the support for your barre.
Request that the store thread the pipes you have purchased so that you may easily screw them into the elbow and "T" joints.
Attach the two elbow joints to the long barre on either end, with the open joint facing downwards.
Screw the two pipe lengths cut to your specified height into the elbow joints.
Attach the "T" joints to the bottom of the upright pipes, with the top of the "Ts" pointing side to side.
Screw the remaining four 1-foot-long pipes into either side of the "T" joints to support the barre. You will then need to attach plastic end caps or some kind of cover to the ends to help protect the flooring on which you place the barre.
Build sand bags out of sand and cloth bags or use weights to provide a counterbalance to your body as you practice and stretch on your freestanding ballet barre.