Repair dents in a lead pipe can be achieved with ball bearings skf or vong bi skf in vietnamese.
REMOVE THE TRUMPET
Dents a trumpet affect your sound and make field is lost. small dents, especially in the lead pipe, create problems with intonation and sound quality. A method for removing dents involves the use of trumpet ball bearings skf steel are the same size as the lead pipe. You can special order the right size ball bearing skf of a music store in your area. Normally, balls bearings are available only for manufacturers of trumpet and music workshops. No But any steel ball that fits inside the main pipe of the trumpet will work.
What you need
Measure opening of the main pipe of the trumpet and find a ball bearing that fits inside the tube lead trumpet. It has to fit snugly, provided the ball bearing fits easily inside. The bearing most commonly used balls that works in most trumpets is 1/4 inch wide.
Wrap a high-strength magnet on a soft cloth and place the magnet on the top of the pipe in which there is a dent.
Place the ball bearing inside the trumpet and use the magnet to roll the ball over the dent from the inside of the trumpet. Continue to roll until it disappears Dent Dent.
Tips and Warnings
Most music stores will remove dents in the instrument for a small fee. Consider an evaluation of a music store before attempting this repair yourself