Tried a different binder ratio on our last sand mold job

Honestly, everyone in our shop swears by the 3% bentonite mix for greensand. Last week on a big gear pattern, I bumped it to 4% thinking it would give us a tougher mold. Ngl, the surface finish was way worse and we got more gas defects. I think the extra binder trapped too much moisture. Has anyone else messed with their binder percentage and had it backfire?

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3 Comments

patricia3176mo ago

My 5% binder test made a mold that crumbled like a bad cookie.

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wyatt_green316mo ago

Rip, that binder test sounds rough. @patricia317 you might need to bump that percentage up a bit. Crumbly molds are the worst.

4

lunakim6mo ago

Yikes, sounds like @wyatt_green31's advice would've made a real concrete cookie out of that mold!

1