Tried a different sand mix for a small bronze pour and it totally backfired

I was doing a small art piece at home, a bronze owl about 8 inches tall, and decided to mess with my usual green sand recipe. I added a bit more bentonite than normal, thinking it would give me a sharper finish on the feathers. Big mistake, lol. The mold held too much moisture and when I poured, it steamed like crazy and caused a bunch of tiny blow holes all over the surface. The whole piece looked like it had acne. I had to spend like three hours grinding and patching it. Learned that even a 5% change in your mix can wreck a pour if you don't dry it out right. Anyone have a good rule of thumb for how long to let a tweaked mold dry before you pour?

2 comments

2 Comments

casey48519h ago

Ever try using a hair dryer on a mold?

mason41722h ago

That bronze owl must have looked like it went through a bad teen movie phase! I once added just a tablespoon too much bentonite and my mold basically turned into a sauna, ruining a simple ingot. I've found even a small change means letting it dry for a full 24 hours longer than usual, just to be safe.