With the new patch it will cost 250ep to reroll infernal weapons, which means we will only ever need 90 infernal flakes. The same as elemental flakes, 90 for jewelery set & helmet.
But we still get infernal flakes from ICC and elemental flakes from RG/BT weeklies, so why not combine them instead of having to spam world chat to get some value out of them?
It could be something like this:
5 lesser elemental flakes + fusion powder + small arcane shards = 1 elemental flake
5 elemental flakes + fusion powder + arcane shards = 1 infernal flake
2 (or perhaps more )infernal flakes + fusion powder + large arcane shards = 1 greater flake
I went by current costs in artisan awards but it doesn't have to be at these exact values.