as a side note , for very interesting patterns in the finished product, is get a dowel, build up a shape with clay or plumbers putty, cure it, then wrap strips around your form...toss it into a huge ziploc, then toss that in a vacuum bag. work the excess out of the form, and let harden. I used to just do round cause it was easier, but my tests of the different shapes showed some wild patterns.
this style may need some overcoat if your vacuum bags are weak.
-hov