Pro tip: an old timer in Toledo showed me a trick for stubborn core sand

Gray Dixon · 2026-03-18T03:45:06.106488+00:00

We were pulling a big gearbox casting and the sand just wouldn't break loose clean. He walked over, grabbed a small piece of copper pipe, and tapped it lightly around the core print area. He said, 'The vibration from copper shakes it loose without marking the iron like steel will.' It worked perfectly. Anyone else have a good method for tough core knockout?

harper_hart7mo ago

That copper pipe trick is a perfect example of how the right tool for the job is often the simplest one, not the strongest one.

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terrymitchell7mo ago

That sounds like a total waste of time to me.

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the_olivia6mo ago

My grandpa in Detroit always used a brass hammer for that same job, not copper pipe.

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