I have been making mugs with tiki faces carved in them. I have made molds that have been working so I can reproduce them fairly quickly. The problem is that the molds chip very easily, leaving holes in the mold which then create unwanted that then have to be smoothed out after the pouring and drying.
My question is: Is one plaster better or more durable than the others? I have been using pottery plaster #1. However, at my ceramics supply company that I order from I see that they have a number of different types of plaster:
Plaster, Hydrocal White with 4500psi compression strength
Ceramical Gypsum Cement with 6500psi compressions trength
Puritan Pottery Plaster with 2400psi Compression Strength
Pottery plaster #1 has a 2000psi compression strength.
I'm going to go out on a limb here and guess that the higher the compression strenght, the harder the plaster. If someone could confrim this, that would be great
Second question: Who has used a "harder" plaster for mold making and what are the disadvantages or advantages you have found?
Still kind of new to the mold making and production process and trying to avoid the years of trial and error, so any information would help a bunch.