Casting speaker cabs from resin.

[quickshift]

I want to have a go at casting some 2 way speakers from resin over the winter (it's too cold to work outside with wood and I want to make something ). This is how I thought the construction process would go but would be pleased to hear from anyone who knows about this sort of thing. The cast resin bits won’t be complicated and will be joined together by wooden mounts – sort of..

Create the internal spaces from polystyrene – make 3 copies.

Build the model of the speaker from clay over one set of polystyrene spaces.

Make a latex mould of the clay model of the speaker.

Place a set of polystyrene spaces inside the empty latex mould – using a support system to keep it in position.

Fill the latex mould with water or polystyrene beads or something so it keeps its shape.

Cover the mould in paper mache (sp?) and let it set to provide external support.

Pour out the beads / water

Fill the mould with the resin and let it set

Dissolve out the polystyrene with suitable solvent.

This is the resin I want to use unless there is anything better

An odourless two component polyurethane system which is deigned for thin sections, or castings up to 20mm thick that require very quick demould times and can be used unfilled. Does not contain hazardous solvents. Good thermal resistance. With low viscosity it produces excellent surface detail and finish. Does not shatter like polyester casts. Simulates polypropylene when fully cured.

Now there are a few questions I have.

What, if anything, is the best filler to use? These are the choices http://www.cfsnet.co.uk/acatalog/CFS...ILLERS_12.html

Will the resin dissolve polystyrene? If so, what material can I use to create the spaces that can be easily removed or dissolved? I need a material I can shape easily but the spaces won’t be that detailed.

What is the best way to keep the detail in places like the driver seats? I’ll obviously drill holes afterwards but want to reproduce the detailed shapes accurately. Is there a better material to use than latex?