I am going to build my own caravan without using a mould.

I would like to know how I can get a reasonable finish on the outside.

I will be using a woven cloth and epoxy resin for strength on both sides. I intend to make two frames 100mm apart using PVC piping (one the outer and the other the inner). Once I have constructed both frames and achieved the shape of the caravan I desire, I will split them up into their sections, walls, ends, roof and floor to enable me to fibreglass on a horizontal level (as it would be impossible to do this on a vertical level).

I intend to use what the builders use, fibreglass mesh, to cover over the frames, both outer and inner, and then either use expanding foam or polystyrene/styrofoam between the mesh as core material. I will then fibreglass using the woven cloth and epoxy resin over the mesh on both sides.

Might seem a little mad but I am not rich but want a challenge and a caravan that will not leak, use vast amounts of gas to heat, be lightweight and aerodynamic.

My question : - how can I achieve a reasonable finish on the outside and what products should I use to do so.

thanks