mkregor got a reaction from High Bridge Pottery in New Plaster Wedging Table Contaminating My Clay
Today I opened the mold, flipped the board over and it's working beautifully -- no plaster comes off! I think it was similar to what you described High Bridge. I bet if I scraped off the top inch or so I'd have exposed solid plaster. Next time I'll definitely mix by hand.
Thanks for all the advice!