Gravity casting seems to be useful dealed with aluminum

 Die Aluminium Castings 'Gravity casting seems to be especially useful when dealing with aluminum and other light alloys. The basic idea behind this castingprocess is pretty much exactly what the name suggests. The metal isintroduced into the mold by the force of gravity. Most othercasting process either use natural pressure difference like thekind in certain sand casting procedures or they use forced pressurelike in centrifugal casting to get the molten metal into the mold. One of the most common uses for gravity casting is when permanentmolds are going to be used. Also called a die, the permanent moldis really only economical for those planning on using the same moldnumerous times and will need to keep the quality at a constantlevel. While some temporary molds can be repeatedly used thequality of the finished product will begin to suffer over time.With die molds the quality will remain the same. Die molds shouldbe seen as an investment. Yes, they will be more costly then othermolds; however they will outlast cheaper options for molds. WithPermanent molds, they are created using cast iron, steel, and othermetals.'