[bergy]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">[/quote]The cores in the cooling cavity of the block are usually made of silica sand,when the block is machined the sand exits from the frost plug and cooling holes.They usually go on a vibrating machine to loosen the particles of sand.Theres more to the process then i mentioned.[quote]</div></div>
Good point Marshall - I'm sure that you know this, but just for discussion - The same resin core binder was used for aluminum and iron. The problem was that aluminum is poured into the mold at a much lower temperature then iron. So, the binder didn't break down (burn up) completely in the aluminum castings; thus the core wouldn't completely exit the casting during shake out. The cores that remained in cooling passages of aluminum castings caused huge problems. At Messina (Vega 390 aluminum blocks) we actually built dedicated, individual shaker fixtures to &quot;rattle&quot; the heck out of the blocks. I did my thesis in graduate school on cleaning of castings and removal of core sand (how anal is that?!).