"Nick Mueller" wrote in message
...
Jon Elson wrote:

I'm not sure the
auto makers use them, either. Either iron or aluminum engine
blocks are usually sand-cast.

I'm sure that at least valve heads (out of aluminium) are cast in steel
moulds. Just the ports and water ways are sand cores. Sand casting is too
expensive for high volume productions.


Nick
--
The lowcost-DRO:
http://www.yadro.de

It depends on the accuracy, size and reusability desired. Plaster, rtv, sand
are common materials. For big
metal objects there are other choices in foundry practice.
There are plenty of good books out there on the processes.

Regards,

Edward Hennessey