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MOULD MAKING STARTS WITH A MODEL
Your Guide to Model Making Using Oil Based Clay

Article Contents:
 

Making A Model for Mould Making

To make a mould you need a model. Taking the time to learn about the techniques of model making and the materials used to make these models, will enable you to cast unique and different products, capable of having the design registered as a copyright.

1) What material to use to make the model

Models can be made from almost any material from plaster, wax, wood metal or clay to mention just a few. For the sculptor clay has much to recommend itself. It can be manipulated easily by hand or by using tools and produces excellent moulds for duplication of the original.

Potters or water based clay is very low cost and can be used but must be kept moist to remain plastic and workable. It also shrinks when it dries out and is very brittle and easily damaged.

Air drying clay can also be used but becomes very hard when dry. It cannot be returned to its plastic form after drying out.

Oven baked clay is similar to oil based clay in that it remains plastic and you can shape it for as long as you like. It is hardened by baking in an oven but cannot be returned to a plastic state once it has hardened.

Plastelina or oil based clay is always plastic. Unlike water based clay it does not dry out and harden. Sculpting can be carried out over as long a period as necessary without the clay drying, shrinking or losing its plasticity.

Plastelina is an economical medium hard clay excellent for beginners to start working with. However there are a variety of oil based clays available such as Klean Klay in variety of hardnesses from extra firm to soft. Both clays are sulphur free, a necessity if making the mould with silicone rubber. Aldax Plastelina can be purchased here.

plastelina non hardening clay
 

2) Tools to shape the model

Wooden Clay Tools: A set of 12 cherry wood tools are available to provide an inifinte variety of shapes to alter the clay surface and is highly recommended. Of the metal tools on the market the type with a cutting edge are to be preferred rather than the cheap wire loop tools seen in the $2.00 shops. Thin slices of clay can be removed easily using this type of tool whereas the thicker wire type is clumsy in comparison and removes far too much clay each time you use it. Click here to buy

clay tools

Armatures to support the clay: Your clay will need support if the model is large or has extended parts such as arms or legs in a figurine and for this extruded aluminium rod or wire can be used. Form the rough shape of the model and attach it to a wooden base on which to build your model.
Simply apply the clay over the armature to complete building up the shape required and then press or carve in the additional detail required.

Click here for Armature Wire on our web store

Click Here for Armature wire
Clay Extruders: An excellent tool we used to good effect in the ceramic industry is the clay extruder. Developed by Kemper in the US it extrudes a wide variety of clay shapes to ornament your model. Simply place some clay in the barrel, select a shape and insert in the barrel, press on the plunger and Hey Presto as many as 18 different shapes of clay can be extruded to make anything from flower posies to walking sticks. Click here to buy
Clay extruder
Texture Pads: The use of texture pads to save a great deal of final carving with your model, is made possible with a wide range of textures available in the form of plastic and silicone textures. These are simply pressed into the clay to leave the desired impression.
Individual textures can be made by pressing silicone putty against any required texture to make a texture mould for years of use.
 

Rolling Pins: A rolling pin is very useful for preparing even thickness slabs of clay for use on your model. For a 1cm slab use two strips of 1cm thick wood and use these to support the rolling pin and put some clay between the two strips and roll out the slab.
There are also some texture rolling pins available for giving a quick texture to your clay.

Click Here to buy

Rolling Pins and tools

3) Sculpting the Clay

You do not need an art school diploma to produce quite beautiful models from oil based clay, it is easier then you think. Try it and see and you will surprise yourself.

The clay is very forgiving, mistakes can be covered or redone if it does turn out right the first time. An excellent idea that I saw a toy soldier sculptor adopt, was to make progressive moulds of you work. Use these as templates not only for a large variety of subsequent finished figures, but also as a base for redoing the sculpt from any partially finished stage, to save redoing the sculpt from scratch.

If an armature is required fix the shaped galvanized wire it to a wooden base by making a loop in the base of the wire and screwing it to the board using a washer to ensure a firm attachment.

If it is a large figure cut some polystyrene foam to pack around the wire and reduce the amount of clay necessary. Start packing the clay around the armature using your hands to press and squeeze it into the rough shape of the model.

Now use the tools to start applying the final detail required. Clay extrusions can be added or textures can be pressed into the clay using texture pads. Little balls of clay can be added to fill out a shape and then refined with the tools.

Texture pads are ideal for cutting the amount of work required if making something like a lizard. A texture shaped like a lizards skin can be quickly pressed over the model's body to give a professional finish in a very short time.

To make a unique texture of your own, simply carve it into a block of oil based clay and make a silicone mould of the carving and there you have your new texture pad. The new silicone putty is another easy way to make a new texture. Mix the Part A with the Part B of the putty to blend together and then press up against the texture you require, say the bark of a tree set aside for 10 minutes and there is your new texture pad ready for use.

4) Finishing touches

To finish your model and give it a smooth surface use some methylated spirits on a soft artist brush and brush over any rough spots. This action will smooth the oil based clay by dissolving it.

We always spray the finished model at this stage with an acrylic sealer to give it the required matte or gloss finished surface and also to prevent the clay from sticking to any mould material such as plaster. Craft Seal Universal Sealer is an ideal sealer which can be brushed or sprayed onto the mode.

All the tools and equipment mentioned in this article can be purchased from our online store or by dropping into our factory. Click Here for more information.

  Stan Alderson Copyright 2011 Aldax Enterprises Pty Ltd       www.aldax.com.au