My uncle swore by adding a bit of borax to the green sand mix

Honestly, I thought it was just an old timer's trick when he told me about it years ago. He said it helps with mold strength and reduces scabbing on the castings, especially with our local clay. I finally tried it on a batch of about 50 small gear blanks last month. Ngl, I was shocked. The surface finish was way cleaner and we had almost zero burn-in defects. I used maybe half a cup per 100 pounds of sand, just like he said. It made me wonder what other simple tips I've been ignoring. Has anyone else tried something similar with their sand additives?

2 comments

2 Comments

nathan_patel1d ago

Nah, that sounds like a good way to mess up your whole mix. I've seen borax make the sand way too brittle.

stone.evan1d ago

Yeah, the "way too brittle" thing is such a classic over-correction. I mean, it happens with everything, like adding too much salt to food trying to fix it.