Bitterman:
Yeah, I don't get this. Aren't both organisations owned by the same people? Why would you go out on a limb with untested methods and materials when there is already a functional and successful version?
Roark
Yeah, they are both owned by the same people (more accurately, one is a division of the other).
However, the vacuum casting method that Forge World is simply too slow and labour-intensive to produce models in the quantities that GW require. There is simply no way they would be able to manufacture sufficient numbers of figures, using FW-style vacuum casting, to meet the demand for models and units in the main GW line. (They struggle to meet the demand for FW, which is a large part of the reason FW stuff isn't sold in any GW store except Warhammer World).
The mistake (idiocy? Stupidity? Wilful ignorance?) they made, was to instead use a cheap (ie. cheaper than metal) resin material, but continue with the same spin-casting methods they'd previously used with metal, to produce Finecast. They can happily churn out vast quantities of the stuff, so that's not a problem... but where spin-casting metal relies on the weight of the metal itself, in combination with centrifugal force, to fill the mould; Finecast resin has practically no weight to it, so it just doesn't work. Hence the huge numbers of bubbles and appalling miscasts from which Finecast suffers, and the huge numbers of detail-obscuring vents and shafts they've added to those Finecast models, in a desperate attempt to work around the problem (with indifferent success).
Of course, we all know that cheaper raw material, plus inherently and unavoidably lower quality, equals higher price. Thanks for that, GW.
So, yeah. tl;dr: even though they're the same company, GW couldn't possibly have used the materials and casting techniques that FW use, to replace the old metal material. The problem is that they
shouldn't have tried to use spin-casted Finecast, either. (The Finecast name has entirely disappeared from their website, BTW, but it's the same shoddy stuff they're using, which is disgraceful).