Casting Difficult Molds

[jupdyke]

Any advice on casting some more difficult molds? I have two that are bugging me recently.

1. A mold of a beer tankard that has the handle attached. I have trouble getting the slip into the handle without any air bubbles. The handle is thin and slip thickens up quickly.

2. The second mold is a large fruit bowl. It is a two part mold that doesn't require you to pour out any extra clay. The top of the mold is the inside of the bowl and the bottom of the mold is the outside of the bowl. I hope that makes sense. The issue is that the two pour holes are very small, about as big as the diameter of your finger. When I try to pour the slip in it doesn't run down into the mold very easily, and sets up and clogs the hole.

The clay distributor said that they can't get talc from their supplier in new york due to some big problem, and now the slip is a lot thicker. He said that I should not add more deflocculent because they have added as much as possible. Has anyone else heard about this?

Any advice?

josh

[username.]

Talc from New York (Nytal) was found to contain asbestos components, and the mine owner/supplier (Vanderbuilt) has been the defendant in a few lawsuits because of this. I think they stopped mining in early 2008. There are other talcs available.