Sand cast would be fine. You need a core to make the inside hole. That will be difficult without cutting the original along the parting line to make the core. Then you need to make core prints, that's plugs sticking out of the holes to locate the core. The core must not be too firm or the casting will crack as it shrinks. The core should crush by the shrinking alu.
1 Yes, you could do that. It may even work for making the core without destroying the original. There is a special silicon rubber for this. You need a vacuum stirring machine to use it.
2 No. You cast a polyester model in the silicone rubber, then you
3 place this in the sand.
The tricky part is the core. And the shrinkage that is quite a bit when casting aluminum. You could compensate by adding some putty to the critical places of your original first to make a machining and shrinkage allowance.
Oh, and don't try to cast it in 6061.
Cut up aluminum engine heads are fine raw material for such things.
And beware of the dangers of casting. Wear a full protection! Even slight moisture in a crevice of your raw material may make it explode in your face. How do I know? Well my visor is aluminized to show how! Other than a need for a new set of underwear I was fine thanks to the protection.  |