Hi there! 
So I'm part of the composites team at UCLA Formula student team and we're looking at using styrofoam as our mold. From my understanding, we need to use Duratex Styroshield to coat the styrofoam before we can start laying up onto it. Does anyone have any idea how this process typically goes and whether it is comparable to using normal duratec gray surfacing primer on high density foam. I have heard that styroshield requires a lot more work in terms of sanding to get it to the desired smoothness. 

Thank you!

Styrofoam and any polystyrene derived foams are sensitive to being dissolved by styrene and the solvents in polyester and vinylester based resin systems, so you need to seal and protect the surface first.

That is where products like styroshield come in.  Sandability can be an issue with epoxy resin.  However for most cases you could use the  epoxy to  seal the foam then coat a typical pattern coat primer or similar material on top and work that to get the smooth finish.

Also if you are hoping to reuse the mould, you might want to consider adding a couple layers of woven glass fibre to strengthen the mould further.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

To use such a pattern with pre-preg would require the whole thing to be capable of with standing the temperatures and being under vacuum.  You would almost certainly need to make a proper tool from the pattern in a high temperature tooling system.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Maybe what you could do is cheap foam female moulds, glass skinned hand finished including flange areas that could be used with vacuum infusion process in normal room temp situation.