As long as you use a slow hardener and quite a good quantity of filler powders, then you should be ok.  The danger with fillers like this is excessive exotherm if the heat does not dissipate - eg you use a small amount of bubbles and fillers.  

By sure the safest way would be to use a casting resin to make the filler paste.  It would already have the slow cure time to help avoid exotherming and can still support a lot of fillers and pigments.  A good one to go for when doing thicker casts would be our GlassCast 50 Clear Epoxy Casting Resin

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

It entirely depends what you are trying to achieve. Vast majority of epoxies are very low odour anyway. 

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Hi which type of epoxy is best for mixing with fillers please? Without lots of smelly fumes too Thanks