Hi,

I'm trying to make carbon tube by hand layup  process. after wetting and wrapping the fabric around the mandrel i wrap peelply, perforated film and breather around it and vacuum it but after curing, the carbon fabric is wrinkled in several places. i didn't use a vacuum gauge but it did seem there was a leakage  .
what could be the reasons? what can i do to avoid this?

thanks
 

It is simply the consolidation of the vacuum causing the excess carbon to crease. Vacuum is not a great way to hand lay tubes, for this very reason. You would likely have more success with a composites heat shrink and roll wrapping the tube.

Sounds like you need to wrap the fibre tighter around the tube.  If it is not tight enough, the fibre will be able to move when the vacuum pulls down and it will compress the fibres forcing it into creases where the excess fabric is. 

What can help is to brush on the first layer of resin to the mandrel and allow it to part cure until firm but tacky before applying the fabric.  The fabric will then stick better to the resin and is less likely to move.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant