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Pro tip: check your flask clamp pressure before you pour
I was working on a small run of bronze plaques last week, and every single one had a weird, wavy edge on the back. I was ready to blame the sand mix or the pattern... spent two hours messing with the moisture content. Then my buddy Carl walks by, gives the flask a little wiggle, and says 'This thing's looser than my grandma's knitting.' Turns out, I'd been using the same old hand clamp for years and just cranking it down until it felt tight, but the threads were worn. I wasn't getting even pressure, so the cope was shifting a hair during the pour. Borrowed a torque wrench from the auto shop next door, set it to 25 foot-pounds, and the next cast came out perfect. How many of you actually measure your clamp force, or is it just a 'feel' thing for you too?
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pat_murray532d ago
Man, you used a torque wrench? I feel like a caveman over here. I just give the clamp a good whack with a dead-blow and call it a day. My whole system is based on vibes and the hope that nothing shifts. Probably explains the occasional mystery fin on my castings.
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wilson.olivia2d ago
Okay but come on, is this really a lab experiment? A torque wrench for a flask clamp feels like overkill. Pat_murray53 has the right idea, a good whack usually does the trick. Most of my issues come from rushing the ram-up, not the clamp. If your threads are that worn out, maybe just get a new clamp instead of bringing car tools into the foundry.
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