TIL that old trick of using a bit of borax in the green sand mix to reduce scabbing actually works, which I doubted for a decade until my pattern guy in Toledo insisted I try it on a big gearbox casting last Tuesday.

I mixed in a half cup per hundred pounds, and the surface finish came out cleaner than any facing wash I've used, so has anyone else found a different additive that works better for gray iron?

3 comments

3 Comments

ninar681mo ago

Ever try adding a bit of wood flour instead? I've had less luck with borax on my heavier sections.

sanchez.ivan1mo ago

Wood flour is a solid shout for bulk. I remember trying to patch a rotted sill on an old shed with just sawdust and glue, made a mess that looked like wet cereal. Ended up having to chip it all out and start over with proper filler. Sometimes the old shop tricks work until they very much don't.

sarah_davis1mo ago

Man, that feeling of being proven wrong after a decade is a real trip, huh? Stubbornly doubting something that turns out to work perfectly. I totally get that mix of relief and slight annoyance. It's like when I refused to switch to a different parting compound for ages, and the new guy in the shop finally made me try it. The results were so much cleaner, just like your gearbox. Sometimes the old tricks are the best ones.