silicon - but silica , an oxide of silicon usually in the

SiO2 family.

Vance

Vance, I agree with you that the castings are
infused with silica. The element used for IC
wafers is, however, indeed silicon. Great care
is used to prevent oxides when making
semiconductors until making insulating layers.
Ok off topic, sorry Paul! Bill Jepson

A> I wonder how far they are infused. I think you can grind off the
A> surface layer and castings will weld fine.

A> Paul Lamar

Don Dunbar wrote:

Hello ACRE,
As I started all this I should finish it. Vance you are right it is
silica sand used in the molds in most Aluminium sand casting. Paul you
are right if the surface is ground back it generally gets rid of it for
welding. In some cases the silica can run deep if the pour has been
too hot. The tensile of sand casting is not that good but this can be
improved through heat hardening in an oven. This was the reason that I
decided to stay with the Mazda pressure cast bell housing as its
tensile is much greater than sand casting.

--
Best regards,
 Don                            mailto:ddunbar@echidna.id.au

Not to mention it is a heck of a lot lighter weight due to the
capability of high pressure die casting thin wall sections with steel
male and female molds. Also it is not sand cast so silica infusion
would not be a problem in welding it.

Paul Lamar
 
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