Showerthought: I had to pick between two different binders for our core sand mix last month.

The choice was a standard sodium silicate or a newer organic one that cost about 15% more per batch. I went with the organic binder for a big job making pump housings, hoping for less gas and better shakeout. It worked great... the cores came out clean and the castings had way fewer surface defects. Anyone else made that switch and noticed a real difference in their finish quality?

3 comments

3 Comments

blair6303mo ago

So you saw a big drop in surface defects? That's interesting... we tried a similar organic binder last year on some valve bodies and honestly didn't see much change in finish. The shakeout was maybe a bit easier, but we still had to put just as much work into the cleaning room after.

thompson.brian3mo ago

What was your sand-to-binder ratio when you tested it?

dakotal161mo ago

Wait, you mean my "scientific" approach of "just keep adding sand until it looks right" isn't gonna cut it here? I kid, but seriously, I started at a 5:1 ratio and gradually dropped down to about 4.5:1 after a few test pours. The lower sand content gave me a noticeably smoother surface on the cast iron parts I was messing with, but I did have to watch for hot tears on the thinner sections. Still, the cleaner breakout was worth the trial and error, even if my notebook looks like a toddler's doodle pad now.