Introduction
This intensive 5-day course is designed for sculptors, model-makers, prop or puppet-makers or anyone wishing to learn more about the process of creating moulds from various types of object and reproducing them as durable casts. Mouldmaking/casting is an important sculptural process in its own right (often the only way to make certain forms) irrespective of whether just one or many are needed. My emphasis during the workshops is on small-scale objects ( and I encourage participants to bring only small test objects with them) because this means that more can be experimented with in the time, and the materials and methods used are almost always applicable to larger-scale projects.
To accomplish the work of the course participants need the test-objects, including both flat one-sided and fully 3D and we can solve that in one of two ways .. or even a mixture of the two! I have my own collection of various objects which I have selected to illustrate the most common challenges when making moulds or casts. These are also of a size which I know to be manageable within the 5 days. I will be sending out photos of them on request, and anyone who wants to can use these for the mouldmaking/casting process throughout the course.
Alternatively anyone who prefers can bring suitable forms with them, whether made or found. One of these needs to be properly 3D i.e. modelled on most sides (such as a head, or a figure .. but doesn’t have to be) and the other two should be flat i.e. modelled from just one side. Full guidance on the options including size limit and complexity is given in the separate document entitled ‘Guidance for bringing test-objects’ which will be sent after application.
Throughout the five days I try to strike a comfortable balance between practical work and the delivery of essential technical knowledge. The practical emphasis of the course is on mouldmaking using a standard, general-purpose silicone rubber and then casting in a few of the most commonly used materials .. principally polyurethane resin, casting plaster and polymer-modified plaster ( aka.‘Jesmonite’, the most commonly known version ). We will be making both simple, 1-part moulds from flat objects and a more complex 2-part mould for a fully 3D object.
Making a 1-part mould just involves pouring silicone rubber as a ‘block’ around it but for the 3D objects we will be using the more advanced technique of thickening the silicone rubber to a paste which can be spread on as a thinner, more economical layer. When silicone is used in this way it needs a plaster support known as the mould jacket to keep it in shape. In addition to casting with the above materials we will also be working with fillers and colourants, and we will compare methods for both solid and hollow casting.
These processes are time-consuming enough in themselves and will collectively take up most of the 5 days but .. especially at times when we can only wait for something to harden, set or cure .. we have the chance to look at more!
We will look at the other different types of mould achievable with silicone i.e. so-called split moulds made in one go but for certain 3D objects; we will look at the alternatives to costly silicone rubber i.e. re-meltable Vinamold; liquid latex; life-casting alginate; even a ‘make your own’ rubber using bathroom sealant and cornflour; we will look at special processes such as cold casting which is a way of creating a true metal appearance using polyester resin; and aborption casting which involves filling an absorbent plaster mould with liquid clay slip to cast i.e. a bowl.
We will make time also to try press-casting in malleable materials as an alternative casting method, and finally we will look at possible methods of painting and surface treatments for castings.
All in all, this is a lot of information to take in over 5 days! To take some of the pressure off you will receive a thorough ‘tech sheet’ covering essential product info and a comprehensive CD dealing with the technical information in more detail, including step-by-step instructions for all the processes covered.
Price & other info
The cost of the course per person will stay at £400 for 2020 and this includes all of the materials used. I also provide many of the specialist tools, but participants are requested to bring a few basic things with them (see Info & equipment list sent after booking or on request)
The course takes place at my studio in Deptford, London postcode SE8 3HF, and because places are limited to 6 each course tends to fill very quickly. Payment (or at least a £100 deposit) will need to be made in advance of the course preferably by bank transfer.
DAILY SCHEDULE
Please note that each day needs to start promptly at 10.00 because there is so much to cover! Lunchtime will be 13.00 -14.00. Each day should finish by 17.30 at the latest, if all is going well, but it may be necessary to stay a little longer if we are getting behind. Usually this can be discussed in advance during the course.
Monday
10.00 Introductions Fundamental principles of mouldmaking and casting.
11.00 Making first half of full 3D mould Preparing prototype; embedding in wax/or clay; mixing and applying silicone ‘skin’ and leaving to cure. When is a ‘barrier agent’ needed?
General properties and uses of silicone rubber, types of mould. Looking at/discussing test-objects. How to decide on the type of mould needed; how to divide it, and anticipating casting difficulties.
13.00 lunch
14.00 3D mould continuing with practical work. Looking at other forms of 3D mould i.e. ‘split moulds’; block 2-piece moulds
16.00 Preparing flat objects for mouldmaking Securing object to baseboard; filling any cavities; building mould walls; mixing silicone and pouring, leaving to cure
17.30 Finish
Tuesday
10.00 Continuing with first half of full 3D mould
Preparing first half for plaster jacket. Mixing and pouring plaster, leaving to set
While waiting General properties of plaster and different types. Different ways of making ‘mould jackets’ i.e. using polymer-modified plaster and scrim; using fibreglass
Starting second half of full 3D mould ‘Unpacking’ and cleaning up first half; applying 2nd half silicone layer (after applying ‘barrier), leaving to cure
13.00 lunch
14.00 Continuing second half of full 3D mould
15.30 Continuing 1-piece moulds in silicone Unpacking and cleaning up cured moulds. Advice re taking care of moulds, extending their life.
Showing further examples of 1-piece moulds
17.30 Finish
Wednesday
10.00 Completing second half of full 3D mould making 2nd plaster jacket, leaving to set
11.30 Making test resin casts in 1-piece moulds Working with polyurethane resin; testing straight resin casting; using fillers and adding pigments
Properties of polyurethane resin; comparison with other resins such as polyester or epoxy; showing examples of resin cast forms
13.00 lunch
14.00 Demonstrating alternatives to silicone
Re-meltable Vinamold; liquid latex; life-casting alginate;
mixing silicone sealant with cornflour (‘Oogoo’)
16.00 Press-casting as an alternative casting method Using polymer clays such as Super Sculpey; Polymorph plastic
17.30 Finish
Thursday
10.00 Making test casts from 3D mould in casting plaster or resin Dismantling and preparing mould; estimating mould volume; mixing and pouring.
Further casts in 1-piece moulds if time remaining ..
13.00 lunch
14.00 Making hollow resin or plaster/polymer casts from 3D mould Mixing and applying 2-part polyurethane resin with thickening material such as Polyfibre; or layering plaster/polymer with scrim.
16.30 Demonstration of ‘cold metal’ polyester casting showing GP (general purpose) and clear casting examples
17.30 Finish
Friday
10.00 Demonstration of absorption casting Showing methods of making hollow casts in plaster moulds using clay slip or latex.
11.00 Continuing with casting in flat or 3D moulds as required
13.00 lunch
14.00 Burnishing ‘cold metal’ castings
15.00 ‘Afterwork’ Methods of painting etc. Showing examples of paint finishes and surface treatments
17.00 Closure and tidy-up.
davidneat 