I have an adjustable paddle and want to beef up the strength of the extension tube which is shaped as per the drawing below.

My thoughts are to laminate some carbon cloth onto the inside (can't do it on the outside for obvious reasons!) but I'm interested in the best way I might go about this.

I figure the best way is to apply resin to the cloth and roll it into a tube with a long/thin party balloon inside the tube, insert it and then pump up the balloon to expand and press the cloth onto the inside of the tube (note irregular shape!). I might need to drill a small hole at the sealed handle end of the extension to allow trapped air to escape.

Any thoughts on this or better ideas or traps for young players to be aware of ?

Thanks in advance!