Hi all, both photos same thing, I have tried with 2 water porcelain ratio first 0.41 liter per kg and also 0.39 liter per kg, settled for 2 days and sieved. I think at this point that the problem is in mold, It is an Italian plaster I used 1 to 1 water plaster ratio, and used soap for demolding. I noticed that bumps in the pieces are the same in every piece, so it must be a mold issue. I made a mold 70 water 100 plaster but it is too thick, pouring very difficult, I'll try with some more water (waiting mold dry)
Giorgio