I have a seat mold that I made a few years ago and want to make a seat from it. It is polyester resin with some fairing compound on it which still needs some sanding.
I will be molding in epoxy with layers of 6 oz and maybe some left over carbon fibre.
What is best for the release fabric? Can I use thin poly? wax paper? West release paper? What about release wax?
Also....Can I vacuum bag it with a trash bag and shop vac?
thanks

I tried vacuum bagging (with a vacuum pump setup) a seat but I found that it didn't help much, and I felt rushed for time getting the cloth layers applied and wetted out. Without the vacuum, I can apply layers and make sure I 'massage' things in place, and it's not a big deal if the first layers start to set up a bit before I'm finished. It makes for a heavier weaker layup, but on a seat I don't worry too much. BTW, if you are using carbon, IMO be sure to put a layer or two of glass on the mold first - it's easy to sand into the carbon later.

As Jay explains, get the mold as smooth as possible. Also (as I learned) make sure your fairing compound is well-adhered and is resin based. I foolishly used some (lacquer based) glazing putty to fill some small scratches and it came right off when I used the mold. When you get your mold sanded smooth, if there are pinholes in the fairing compound, I'd try painting on some resin or gelcoat to get a smooth hard surface.

Copying a commercial seat pretty well guarantees that there will be proper draft on the mold - i.e. that the mold won't try to trap your product with any 'reverse curves'. If you are using your own mold, you need to be careful about that...though with epoxy it's possible to pull the workpiece when it is still a bit flexible. Some thin (hard)wood wedges can help there- you don't want to scratch your mold with putty knives, etc..

I use PVA mold release (sprayed on with a cheap jamb gun) but I may try the Saran Wrap TM (Glad Wrap? Stretch pallet wrap?) next time.