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How to cast pieces with attachments
Casting and assembling the greenware of a porcelain figurine may be a challenge for you; particularly if your piece is a box, requires add-ons, stick-ons, or special timing. If you're not sure what all that means, read on; this is written just for you.
You might wonder why a manufacturer would torture you in this way (i.e. multiple molds for just one figurine); let me assure you it is avoided as much as possible in order to make molds as user friendly as possible. However, some special shapes, usually the very designs most coveted by dollmakers, (you know, the sweet delicate details that make you go ahhh) are impossible to get out of a mold without some special treatment. This treatment requires more than one mold. Think of it as "some assembly required". I will go to great detail and explain why you do each step in the hope that you will then be able to tackle any design with confidence. Use the following as a general guide. It really is as easy as 1 - 2 - 3 once you know how!
First, when you cast a piece that required assembly with a few attachments, all of the pieces need to be cast at the same time. You will want to do the attaching in the leather hard state. All the pieces should be of the same moisture for good bonding.
2. Second, you need know which pieces should be cast hollow and which should be cast solid. Any piece that is added on to the main piece will need to be vented through the main piece. This means that a hole should be made on the bigger piece corresponding to the hollow part of the piece to be added. This will allow any air, which might be in that hollow, to escape through the hole and into the air. If the air in the hollow part is not allowed to escape through a hole, it will in fact escape any way creating a hole perhaps not where you want it and possibly even blowing the attached piece off with it. If you forget to vent the arm of a figure, you might open the kiln and find it stuck to the side of a neighboring doll’s face on the same kiln shelf. So, if in doubt on your first attempt, you might want to leave a little extra room around that piece on the shelf. Once you have done one or two attaching sessions, you will be a pro and this will be unnecessary.
3. Third, you should use the same porcelain slip with which you cast the piece and a little water to "stick" everything together.
4. Work on a banding wheel or lazy Susan to be able to get to all angles of the pieces with a minimal amount of handling. You will need a feather knife, soft rounded brush (KwikClean), a small amount of the porcelain slip in which you cast the piece and a little water.
Investigate where the attached pieces will be added on, then score (crosshatch the surface to rough it up for a better bond) the area with the feather knife and create the ventilation holes. Working one piece at a time, brush the surfaces (where the two pieces will touch) lightly with water and then with porcelain. Place them carefully into position. Use the brush, and back of the feather knife to smooth the areas where the attachments come together. Fill in where necessary with more porcelain, again using the brush.
If the piece has many attachments, work from the bottom up, so that you don’t get in the way of what you are adding. Or, refer to any suggestions a specific article or worksheet may have on a specific piece.
Soft fire to cone 018 and clean as usual in the dust free cleaning technique™.
Some hints:
You might find it easier to somewhat clean the pieces around the seam lines with a damp sponge before assembly as some angles become hard to reach afterwards.
If your piece is a box, it is a good idea after the box halves are very firm, but not dry, to place them together so that they dry into a good fit.
After soft firing and cleaning, the pieces may be high fired together using a separator. Use Seeley’s Separator that comes in a small squeeze bottle. It is very easy to use. Squirt the product from the bottle onto where the two pieces will join; allow to dry, place pieces together and fire to cone 6. Brush away the residue after firing.
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