When making a mold, is there any basic theory I should know about choosing either (a) number of sprues, (b) location of sprues, or (c) thickness/shape of sprues?
Does increasing the number or thickness of sprues necessarily mean less bubbles in the finished cast? Should all of my sprues be the same thickness?
Background: I gravity cast with a two-part RTV silicone mold. I use SC 321 mostly. Sometimes SC 327.