This week I am testing casting slip as part of investigating porcelain as an option for my ceramic furniture. First, I tested the casting slip to see how it fired using these furniture molds.
The tests revealed that the NS-124 Antique White Porcelain Slip by Laguna had the best surface at cone six. The table leg molds I had needed to be re-made because they were designed for press molding, not slip casting. I pressed the the table leg again, and made it in one piece to set up for molding. Here, the table leg is set up with clay to make sure that the plaster only casts one section.
After one side is cast, the mold is keyed and soaped with release agent so that the next piece can be cast. With these carvings I have to be careful not to make them too deep or complex so that the plaster doesn’t lock onto the forms.
The mold of the complete table leg is much larger and heavier than the press molds. I had to use heavy duty straps to keep it tight enough to hold the amount of slip that had to be poured in to fill it. I filled the mold with it inside a bucket just in case of a leak.
Here you can see the finished cast ready to remove from the mold. The cast will have to be cleaned up and have the seam lines removed, but this process will allow me to create detailed porcelain table legs very quickly.
The next stages of problem solving will involve creating a table top that is also slip cast and works with the legs. I will also have to deal with possible slumping of the porcelain during firing, and maybe create some firing supports to combat this. I will have to re-mold the figure heads like the dodo, and other small sprig pieces to work with the casting slip.