: Usually one adds the hardener to the resin, mixes it well, and then
: adds filler material to suit one's purpose. Perhaps adding the
: filler before the hardener caused an imperfect mix.

: Et

I have made up three batches with two different resin systems (West and USComposite) and they all worked out well. I must have simply forgotten to add the hardner.

I always mix the fillers into the resin first, because it gives a longer net pot life. YMMV.