In this video I show various tips for successfully pouring ceramic and porcelain beads.
Some Tips for Slip Casting Beads and other small objects
Pour down the side of the spare to avoid hot spots (hard spots that don't take glaze well) and to avoid trapping air.
Keep the spare full so you can see the buildup of the slip around the edge. Keeping the spare full will also help avoid collapsing of the casting especially if you are trying to pour things solid.
Consider the clay body you are using when deciding how thick to pour your beads. Low fire earthenware bodies such as ceramic and terracotta have far less strength than high fire bodies like stoneware or porcelain and should be poured thicker.
Using an aquarium pump with a small glue tip on the end will help in draining a small mold. But be careful not to stab the spare with the glue tip or it will clog and not blow air.
Do not attempt to pour large beads solid. They will be very heavy and are prone to collapsing especially if they have small pour holes as the pour hole will close over before the slip in the cavity has totally absorbed creating a sort of vacuum effect that will pull the casting away from the mold edges.
If you are attempting pour a mold solid and the slip in the top of the spare has quit sucking down into the mold it is sometimes helpful to insert a long needle tool directly into the center of the pour hole. This will re-open the pour hole and allow further absorbing without collapse. Do this several times until you have a hole down the center then turn the mold over for a bit to redistribute any remaning slip in the mold. After it has set for a bit poke the hole with the needle again to insure that air can enter the mold.
If you are having difficulty draining a mold use the needle tool to open the pour hole slightly to allow you to insert the glue tip into the cavity.
Once you have drained the mold set it upside down on a raised surface to finish draining. I use an old refrigerator shelf.
After draining is complete lay the mold on its side. (seam line horizontal) This will aid in the release of the item from the mold. Some molds will release better if laid on a specific side. You may notice this after several pours. If you do mark the mold 'this side up' to remind you which way it works best.
Here is a close up view of pouring another mold that you can see the thickness of the casting better.