Wish I had listened to the old timer about casting temp
A retired guy at the supply house in Pittsburgh told me to run the pour a solid 50 degrees hotter than the book says. I figured he was stuck in the past, so I followed the chart instead on a batch of valve housings. 14 cracked castings later and a whole weekend scrapped, I finally get why he said what he said. Anyone else fight the urge to ignore the experienced fellas?
Man I feel this in my bones. Had an old head tell me the same thing about running aluminum hotter than the spec sheet and I brushed him off cause what does some guy in a dirty shop coat know that the engineers don't. Blew a whole run of intake manifolds with cold shuts and porosity that took me two days to clean up and remelt. The book temp is a starting point, not gospel, cause it don't know about your furnace, your humidity, or how fast you're pouring. Those guys learned the hard way back when scrapping a batch actually cost them their paycheck. Now I write down everything the old timers say and test it myself before I decide they're wrong.