+x Hanaldo - 10/29/2020 12:26:25 AMYes for general pattern work for use at ambient temperature, use anything you like, at the end of the day its about having a hard shiny surface and doesn't matter too much what is underneath it.Unfortunately pre-preg makes that quite a lot more complicated, because your surface also needs to be hard wearing and temperature resistant/stable and compatible with epoxies at high temperature - which regular fillers and paints are not. The one way you could potentially do it is if you were milling the plaster of paris on a CNC. Then you could mill the plaster slightly undersized, coat it with a high temperature epoxy gelcoat or resin, and then mill it back to true size. Works in theory a little bit better than it works in practise, but you can get there. Unfortunately epoxies aren't going to polish up super nicely though, atleast not compared to other coatings, so it is still a compromise. Plus if you are using it as a mould rather than the pattern, you have to worry about the durability of the material and how stable it is going to be. It is less than ideal for sure. For pre-preg, unfortunately you're either choosing between cheap or effective. Adding heat to the equation really makes the process quite unforgiving, and personally I feel it is cheaper to do it once and do it right than to do it 2 or 3 times the 'cheap' way.