I've roughed out a foam plug for some new bodywork working off cad drawings. I've used celotex type low density insulation and i'm now looking to start coating and filling. I was considering covering the foam plug in a fibreglass skin and then building up the finish in layers of polyester primer filler. Can you recommend a suitable cloth and a whether I can use a polyester resin or ?. I have made the plug approx. 3mm smaller than the finished item to allow for a finished build up. ( I attach a photo pre sanding to give an idea of curvatures. Thanks

I would think about a single light layer of fibreglass, either a tissue/vale fibre glass, a light CSM or a light glass cloth.

If your foam is a ridged polyurethane then you can use polyester or epoxy resin.

If your foam is something like a polystyrene or Styrofoam then you can only use epoxy. Styrene resins will dissolve it.

Like Hanoldo said, test a bit of your foam first.




It's a bit risky to try and paint straight onto foam as you need to sand the surface, if it gets too thin then it just digs into the foam and makes a hole. Better or safer/easier to have a hard surface behind the paint.