RE: Thinning Epoxy Resin
You need to be very careful when thinning with solvents. The solvent must a) evaporate completely before the epoxy begins to stiffen and b) not dissolve your release system (if you're molding something).
The problem is that condition a is very rarely satisfied... resulting in measurable decreases in physical performance (strength, Tg, etc.). Also, alcohol is terrible in that it is very hygroscopic and the resulting water contamination will really cause problems with the epoxy.
If you need to reduce the working viscosity of your epoxy... just warm it up and use a slower hardener if needed.
-David