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

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

Paul Lamar

  Part of how deep the sand is in the surface depends to some
extent on luck and to some extent on skill. Wet sand is a bad thing
when you pour hot metal on it.  The steam expansion causes
explosions flinging molten metal in all directions.  Dry sand
is a good thing but... too dry and you get loose sand in the cavity
(at the best)  and who knows where it will end up in terms of
depth in the surface.  Just right sand -  takes experience and
skill and I think some luck.  Then you just get the surface
skin to deal with       Bryan in Princeton B.C.

Thanks again Bryan you are always a fountain of useful info.
I have had very good luck with my foundry. I see none of that.
American International in San Fernando CA.

Paul Lamar
 
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