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Heads up about the new silica sand batch from the Rockford supplier, had a major binder reaction last Thursday.
We were running a standard iron pour, nothing fancy, when the molds started cracking during cooling. Lost the whole set of six engine blocks. Turns out the new sand shipment has a different clay content that messes with the sodium silicate. Our lab guy said the pH is off. Cost us a day and about $4k in scrap. Anyone else getting sand from Midwest Aggregate this month? What binder ratio are you using to compensate?
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elizabethhayes1mo ago
Just saw your post and winced. Classic case of the supplier changing the recipe without telling anyone. Our place got burned last year by a different batch that made the cores crumble like stale cake. Had to switch to a backup resin for a week. Hope your lab guy figures out the new mix fast.
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felix_lane991mo ago
Wait, are you sure it's the supplier changing the recipe? Sometimes our lab messes up the curing cycle and it looks just like a bad batch. We had that happen once, blamed the supplier, and it was totally our oven. Could your lab guy check their process logs first before chasing a new mix? Might save a lot of time.
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