Question:

How can I make a mould?

Air bubbles

Air bubbles (pinholes) in greenware can come from air in the slip from stirring too briskly or pouring too rapidly.
Air bubbles on rims of pieces can be reduced by rocking the mold while pouring.

How to

How to Slipcast Ceramics
Slipcasting is a widespread ceramic technique, suitable to the manufacturing of multiples. A plaster mold is required.
Here's How:
If your mold consists of several pieces, tie them together with thick rubber bands or something suitable to the molds size.
Stir your slip thoroughly with a clean stick, but without introducing air bubbles into the liquid.
If you have a very large bucket of slip, pour an amount into a smaller container, which will hold enough slip to fill your mold.
Pour the slip through a sieve into your dry mold. (Straining the slip eliminates any lumps from getting through, which would otherwise stick to the wall of your pot.)
You will be able to observe the slip adhering to the mold and thickening. At this stage it is possible to gently knock the sides of the mold (let's say with the ball of your hand or with a rubber mallet) to free any air bubbles which may be trapped in the clay. These will rise to the surface.
As the clay wall thickens, water is absorbed by the plaster and the level of the slip will drop. Continue pouring small amounts of slip into the mold to top up the level to the top edge.
When you think that the correct wall thickness is reached, pour all the slip out of your mold back into your bucket. It is possible to time the period the slip stays in the mold, but this will vary in subsequent casts, depending on the moisture content of the mold.
Depending on the thickness of your clay walls and the moisture content of the mold, the ceramic object will be dry enough to remove after several hours.
As the clay will shrink, whereas the plaster will not, the ceramic form will shrink from the mold and 'pop out', if the form allows it to.

Tips:
Make sure you have enough slip to fill your mold.
Have an extra empty bucket handy.
Clay and plaster do not mix -- make sure not to get plaster into your slip!

One-piece molds.

The simplest mold to cast is the one-piece variety. There is no need to band it. It is easily drained and, in most instances, the casting comes free without difficulty.

Gang and Core

A gang mold is what the name implies, a gang of molds made into one. Chess sets are usually gang molds.
Core molds are very similar to gang molds except that they have only one pour gate that branches inside the mold

Sand Seams

After the bulk of seam lines have been removed with a tool, the next step is to sand the lines with a sander sponge.

Separation in mold

If a plate or bowl separates into two layers, either you opened the mold too soon or you drained it too soon.

Alternative

You don't have to mess with plaster to make molds. You can make your own from bisque. Fire the bisque at a high enough temperature to give it strength, but low enough that it is still porous so the clay dries and does not stick. To make a bowl mold, throw a solid piece on the wheel, smoothing the edges well with ribs, etc. When it is leather hard hollow out the inside until your edges are about 1 inch thick. Fire.

“cases”

Did you know that “cases” are the frames around a block used in the formation of ceramic molds?

Facts

A mold is like any other too in that it will wear out after prolonged use.
Molds are expensive and should be cared for properly like any other investment
If you have poured a mold a number of times and it shows wear it is possible to scribe some of the detail back by carefully carving with a sharp tool.

Ceramics Frequently Asked Questions

What precautions should I take in the studio?

How do I decorate my ware?

How do I apply Lustres?

How do I market my ceramics?

How do I apply glaze?

How do I market my ceramics?

How do I fire porcelain?

How do I cast slip?

How do I fire an electric kiln?

How do I apply glaze?

What are some stoneware glazes?

What Precautions when using dry ingredients?

How do I apply glaze?

How do I apply opaque stains ?

How do I wedge clay?

How do I apply Stains?

What is Lustre?

What should I keep in mind when designing my studio?

How do I make a coil pot

How do I decorate my ware?

How do I make molds?

What is Clay?

How do I apply glaze?

What is a decal?

How do I clean Greenware?

How do I add texture?

How do I centre my clay?

What tools do I need to start potting?

How do I start a business?

How do I best promote myself and my work?

How do I load my kiln?

What are ceramics

Where do I start?

How do I make a simple mold?

How do I fire Decals?

How can I make a mould?

What are some life quotes?

What is underglaze?

What is Porcelain

How do I care for my brushes?

How do I care for my molds?

What is Celadon?

What is the Tea Ceremony?

How do I care for my kiln?

How do I apply one-strokes?

What safety aspect should I keep in mind when working with glazes?

How do I apply Lustres?

What is Overglaze?

What are oxides?

How do I fire Bisque?

Where do I begin?

What should I remember when firing the kiln?

How do I clean brushes?

How do I slump/sag glass?

How do I apply overglazes?

How do I best publicise my business?

How do I make a simple plaster mold?

How do I care for my brushes?

Are stains safe.

How do I fire overglazes/lustres?

What is a reduction firing?

How do I doccument my work?

How do I create fine feature lines?

How and when sholuld I apply underglazes?

How do I make molds?

What is an engobe?

Are they Water or oil base stains?

How do I hold my brush?

How do I store my Materials?

Are any two kilns are exactly alike?

What is mould in clay?

What is a Pyrometric Cone?

Do I need a cone?

how do I throw clay?

Can I use sand to stop glaze running onto shelves

How do I test my glazes?

How do I apply China Paints?

Does greenware need to be dry before loading?

What are some life quotes?

What is the history of the Potter´s Wheel?

How do I fire lustre?

What is a glaze?

How do I fire lustres?

What is The History of the Way of Tea

What is Celadon (Cheong-Ja) - the Stuff of Kings?

How do I dry overglazes?

What is a glaze?

How do I Burnish?

What is an overglaze marbleizer?

Is there a trick toThrowing Porcelain?

Have you some lovely words?

What is Earthenware?

What is a glaze?

What are some stoneware glazes?

How do I paint Eyes?

How do I Recycle Clay

How do I attach wet pieces?

How do I make a teapot?

How do I make a plaster mold

What are some good tools for decoration?

What is Kiln Wash?

How do I glaze my ware?

How do I slipcast ceramics?

What are some life quotes?

how do I dry my ware?

How do I fire my ware?

How do I apply texture to my piece?

What is a Glost firing?

How do I make my own glazes?

What are some change quotes?

How do I store my tools?

What is the history of Raku?

What is Paperclay

What is a crackle glaze?

Do I need kiln wash for bisque?

How do I refire a glazed piece ?

What is reduction?

What must I remember when Raku firing?

How do I add decoration to my ceramics?

How do I care for my elements?

Does over firing produce poor colour in coloured glaze?s

How do I use my brush?

How do I care for my brushes?

How do I recycle clay?

What are some success quotes?

What is a glaze?

How do I clean Greenware?

How do I make coils?

What are some Black Firing Tips and Tricks?

What is the safest way to pack my ceramics?

What are Formulated clays?

How do I do a reduction firing?

automatic kiln sitter, should I trust it?

How do I care for my molds?

What are some tips for draining a mold?

What is a decal?

What safety measures should I take with Raku Firing?

How do I attach a bat to the wheelhead?

What tools do I need for ceramics

What are suggested plate clay weights?

What do I need to get started?

What are observation holes ?

What tools do I need to make a coil pot

How do I fire ceramic bisque ?

How do I recycle batches of clay quickly

How do I care for my molds?

How do I fire my ware?

How do I roll a slab?

How do I fire my kiln?

What is the correct firing time?

How to I prepare and make slabs?

What is Leatherhard ?

What materials are toxic in Ceramics?

How do I fire glaze?

What are slabs?

What is Korean celadon?

How do I fire Raku?

How do I make paperclay?

Can Crackle glazes be used for food?

How do I avoid S cracks in wheel thrown ware

how do I apply glazes?

How do I get the press onside?

How do I open-up the clay?

How do I fire Reds/Yellows?

What is a glaze?

How do I fire Ceramic glaze ?

Can I repair my kiln?

What are the Approx. firing times?

Ho do I avoid pitting and pinholes?

How do I make throwing ribs?

What is Stoneware?

How do I care for my molds?

How do I apply kiln wash?

What is a Stain?

What is a mold?

How do I decorate my ceramics?

How do I remove mold lines?

How do I cut the spare?

What is a ´good teapot´?

How do I Bisque fire in an electric kiln?

How do I keep a kiln log?

How do I paint Eyes?

How do I decorate my ceramics?

How do I apply crackle glazes ?

What is Primary clay?

What are some easy projects?

What is Thermal Shock?

What effects can I achieve with a brush?

What are cones?

How do I Drain small pour holes?

What is Glaze?

What is Raku?

How do I remove a stuck lid?

How do I glaze my ware?

How do I make Egyptian Paste?

How do I apply texture?

What is overglaze/lustre?

Must my kiln be level?

How do I make my own brushes?

What clay should I use?

How do I apply a decal?

How do I clean my greenware?

What is Agate ware?

How do I care for my new Kiln?

How do I make stamps?

How do I load my kiln?

How long do I fire bisque?

How do I promote my work?

can I draw directly onto a piece?

How do I increase my profile?

How do I fire different bodies?

what is porcelain?

How do I make test tiles?

What is Earthenware?

What is the humming in my new kiln?

What should I remember when firing a new kiln?

How do I mend Greenware?

how do I get the best results in glazing?

How do I prevent dirt on my greenware?

How do I accomodate Clay Storage in my studio?

How do I fire Larger pieces ?

How do I prevent sagging during firing?

How do I brush one-strokes?

How do I load my brush for applying underglaze?

How do I mend molds?

Why should I use pottery plaster?

What is the coat coverage ?

How do I prevent glazes from settling ?

How do I fire lace figurines?

What is Albany slip?

How do I create a woodtone effect?

How do I light my Gas Kiln?

What is a pyrometer?

What is a Binder?

What is a glaze?

What are some Doing well Quotes?

What is Slip casting?

What is a Rib?

What is a Bisque?

How do I care for my elements?

How do I fire porcelain?

How do I store my throwing tools?

What is the History of tea?

What is the history of Ceramics?

Why do I get black spots in my glaze?

How do I fire flat pieces?

What is Terra-Sigillata?

What are Pyrometric Cones?

What is Iron Oxide?

How do I load my kiln for a glaze firing?





Not finding the advice and tips you need on this Ceramics Tip Site? Request a Tip Now!


Guru Spotlight
Alexis Niki