Switched from a 50/50 sand mix to 70/30 for our greensand molds last month

Always thought the extra clay in the 50/50 mix was needed for strength, but our foreman, Mike, showed me how the 70/30 mix at our Tacoma plant cuts down on gas defects. We ran a test batch on some heavy flange castings and the surface finish was way cleaner. Anyone else try adjusting their sand ratios for different jobs?

3 comments

3 Comments

the_cameron10d ago

Lol, "sweet spot is a band-aid" is a wild take from @kim_davis. Sometimes the old standard just needs a tweak for new problems, like your gas issues. Sounds like you found what works for your shop.

rowanw9110d ago

Yeah we had to tweak ours for some complex cores. That extra clay in the 50/50 can really hold moisture and cause issues. Found a sweet spot around 65/35 for our stuff.

kim_davis10d ago

That "sweet spot" sounds like a band-aid. The 50/50 mix is standard for a reason, it gives you the strength you're probably losing at 65/35.