Hi All We have found that for some jobs we can reuse casting plaster,
up to 25%.For silver castings which are large and the casting temp of
below 500C. Let the old plaster stand and drain off the water,dry off
in the burnout furnace as it cools down. Place in ball mill to make
into fine powder(we have found that an electric cement mixer with
acover works very well , this can also be used for burnt low grade
scrap). When mixing plaster use less water than for 100%new.
Regards
David Sheard
PS when I get time how to make a tumbler for 20$