Re: ATM - Casting Aluminum

[William E Byrd <web01@flash.net>]

Dwight Elvey wrote:

>  Even oven dried concrete has water in it that will come
> out at the temperatures used to melt aluminum. This is
> how concrete cement is made. They have a high temperature
> rolling furnace that heats the gypsum until the water
> comes out of chemical bond. When you add water, it
> recombines and makes cement. This is a fully reversible
> process. Heat it again and it turns to powder.
> Fused cement doesn't have enough relief to let the water
> out and tends to blow up.       <rest snipped>

The things you learn on this list! That's why I keep reading. 
Thanks for the explanation.
     Bill 
-- 
        Bill Byrd       web01@flash.net         San Antonio, Texas