Why does nobody talk about sand mixing time for no-bake molds?

I spent 6 hours last Saturday fighting a batch of no-bake sand that just would not set right. Turns out I was only mixing for 90 seconds when the resin we use at Johnson Castings needs at least 4 minutes to fully activate. Has anyone else had a similar issue with their binder system taking way longer than the label says?

3 comments

3 Comments

rubyk8628d ago

Cut your mixing time in half for the first pass and then go for the full 4 minutes once the binder is actually wet. I learned that trick the hard way after ruining a batch of core sand because I was rushing. Also check your resin temperature, cold resin makes it way worse.

jamesfox28d ago

Just saved me from another cold resin disaster @rubyk86, now who's gonna fix my frozen fingers?

the_sandra26d ago

Exactly what I needed to see after spending last night hunched over a mixing tub with fingers that looked like frozen hot dogs. @rubyk86's method is the real deal though, I cut my initial mix time down to about a minute and a half and it made a huge difference in how the resin coated the sand. Still ended up with cold hands, but at least the batch didn't turn into a solid brick, so I'll call it a win.