Materials: What Materials Are Available and How Do Their Properties Differ?
There are many materials are available to use when modelling and sculpting your work. This article discusses the potential uses of clays and waxes when modelling.
Modelling can be useful for goldsmiths as a way of planning, refining and producing their work. Producing master patterns and wax models is a part of the casting and small batch production process. Understanding the various options available will help you to select the right materials for each job. The main modelling materials can be broken down into two general groups; waxes and clays.
“Modelling can be useful for goldsmiths as a way of planning, refining and producing their work…understanding the various types of materials available will help you to select the right materials for each job.”
Modelling waxes
There are three main types of modelling wax; slush wax, dental wax and carving wax.
Slush and injection waxes are non-residual and leave no contaminating chemicals or blockages behind during melt-out from casting moulds.
Dental wax (Astynax) and blue carving wax both come in sheet form and contain stabilising resins which toughen the wax but can leave some residue behind in moulds.
Powder-filled modelling media and waxes are unsuitable for lost wax evacuation, so must be rubber moulded and converted to slush or injection waxes for casting.
See the table below for further information on slush, dental and carving waxes.
| Name | Sheet Dental Wax (Astynax) | Hard Blue Carving Wax | Slush Wax |
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Modelling clays
Modelling clays include Plastiline, Plasticine, harden-able modelling clays and resins.
Plastiline is a non-toxic, non-drying, non-hardening modelling medium composed of oils, mineral waxes and filler powders and is supplied in a variety of hardness’s to reliable and exacting quality. The grades are:
| Grade | Work temp | Hardness | |
|---|---|---|---|
| 40 | Very soft | Softens at 39 - 41 °c | ShoreA 15-19 |
| 50 | Soft | Softens at 48 - 52 °c | ShoreA 28-32 |
| 55 | Standard | Softens at 52 - 56 °c | ShoreA 48-52 |
| 60 | Hard | Softens at 56 - 58 °c | ShoreA 58-62 |
| 70 | Very hard | Softens at 58 - 60 °c | ShoreA 65-75 |
It softens well with a hair dryer or in a slow cooker, even down to a liquid and can then be applied with a spatula or palette knife to the workpiece. When in liquid state be sure to remix it as it separates out and oils float to the surface. Overheating degrades it. It is supplied in 5 kilo tubes in colours of ivory or grey.
Plasticine is an additional filled modelling clay. I have found it to be of variable quality - sometimes hard sometimes soft and it progressively hardens when held in stock. Ultimately it becomes brittle. It is sufficient to observe that other, better modelling waxes are available. So many that it is not possible to review them all here.
There are a variety of hardenable modelling media available, e.g. Super Sculpey, which after modelling can be baked in the oven. This is useful in order that subsequent layers of modelling can be applied safely without distortion of the original stratum.
Of late, car body filler resin has been used to build up models’ layer upon layer. This can be carved, filed and sanded very accurately indeed. Furthermore, the catalysing action of this mixture ensures speedy manufacture with little downtime awaiting hardening off.
Conclusion and further information
Choosing the correct materials for your project is important and the information provided here will help you to select appropriately.
There are many reputable sources of information relating to the jewellery, silversmithing and allied industries. Whether you are trying to find information on technical skills, processes, materials, makers or inspiration some resources relating to modelling can be found below:
The Goldsmiths’ Company Library relates specifically to gold and silversmithing, jewellery, assaying and hallmarking, precious metals, and the City of London and its guilds. The Library includes 8,000+ books and 15,000+ images, magazines, periodicals and journals, technical guides, films, special research collections, design drawings produced during the early and mid-twentieth century by British or UK-based craftspeople and subject files on a wide range of industry related topics. The Library is also responsible for the Company’s archives, which date back to the 14th century.
Modelling related articles include: