Using a mold is a great way to replicate a hollow form. In this post, I will show you how to make a plaster mold for casting multiple clay pipes.
This solid wood pipe was carved by my partner.
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Make sure there are
no undercuts in your
template. |
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Marbles can be used to make
"key" holes, to keep the
pieces of the mold lined up
when casting the clay. |
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| Dish soap makes an effective and inexpensive resist. |
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| 2 plaster : 1 water |
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| Flick and Splatter, then pour. |
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| Hammer the bubbles out. |
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| Cure (exothermic reaction) |
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| Remove from form work |
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| Piece # 1 |
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| Make form-work for second piece |
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| Pour second piece |
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| Piece # 2 |
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| Make form-work for third piece |
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| Pour third piece |
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| Pieces # 1, 2, 3 |
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| Make form-work for fourth piece |
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| Pour fourth piece |
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| Pieces # 1, 2, 3, 4 |
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Use old bicycle inner tube's, for industrial
elastics, to hold your mold together. |
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Pour your slip and watch the plaster suck up the
moisture. If the level gets too low, top-up.
Depending on the thickness of the plaster, it will
take anywhere from 20 minutes to an hour for
an appropriate clay cast to form inside the mold.
When the cast reached the thickness you desire,
turn the mold upside-down over a pail and empty
the remaining liquid clay. Put the mold on
a rack and leave it to dry. |
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| Once clay cast is leather hard, gently remove from mold. |
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| Make sure there are no pieces of plaster lodged in clay. |
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| Patch hole where spout was and add any finishing touches. |
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| Bisque, Glaze and Fire. |
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The mold is reusable.
Make sure it is completely dried out
before making your next cast. |
Do you sell the molds?
ReplyDeleteCurrently, I do not.
DeleteHow did you get the hole from the bowl to the end of the stem? Lay a stick down or something? Also, I assume you're using a kiln to fire the final?
DeleteThanks!
Plaster molds suck water from clay slip, resulting in hollow casts. The dry pipes are fired in an electric kiln.
DeleteHello REBECCA: Love your work. Do you happen to sell molds? With MJ being legal next month would like to try my hand at slip casting. As you know, ceramics shrink a lot so would be easier to buy a mold rather than hand carving a master.
ReplyDeleteThanks
Jim
jkcorrie@mts.net
Hi Jim,
DeleteI do not sell plaster molds. I hope you find something that works for you. Thanks for your lovely comment and for stopping by.
So if i make a mold is there a certain moisture content i need in the mold? And when i cast it how do i hollow the inside?
ReplyDeleteThe plaster should be completely cured and dry before pouring the slip. Plaster molds suck water from clay slip, resulting in hollow casts.
DeleteJust stumbled on this. I like how you do the box. Way less complicated than how I was taught. Great design too
ReplyDelete