Resin

Introduction

Resin is a naturally occurring substance which comes from certain types of coniferous trees. However the Resin that you buy for sculpture work is a synthetic product known as Thermosetting Plastic, which means it is a plastic that sets at a high temperature. Resin needs the aid of a hardener to form the liquid resin into a solid.

There are two main types of Resin; Polyester Resin and Polyurethane Resin. The most common types of Polyester Resin are General purpose Resin and Clear Casting Resin. The most common types of Polyurethane Resin are Rigid and Impact Resistant Resins. The main difference between Polyester and Polyurethane Resins is that the latter is much stronger and denser which lends itself well to smaller models which require very fine detail. For producing different effects you can use various pigments and fillers by adding them into your resin mix.

Pigments available are either opaque (cloudy) or translucent (semi-transparent). Fillers are used for either the same reason as pigments ie, for the aesthetic purpose (the look), to improve the hardness or scratch resistance or to reduce the heat (exotherm) build-up if casting very large pieces. Also available is Polyurethane Foam which is a two part resin mix and expands up to 6 times its initial volume. It is usually used as back fill for hollow casts where more strength is required.

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Techniques

Laminating with Polyester Resin

Laminating is the process of embedding Resin into Glass Fibre Mat (or as its commonly called, Chopped Strand Mat) to make Fibreglass. Fibreglass is amazingly strong and is a very adaptable medium. It is most suitable when a strong hollow or thin form is required. Make sure whatever you are Laminating over has the suitable parting agent applied to it, unless it is made from Polypropylene, Acrylic or certain types of Rubber. For this reason the best mixing bowls and measuring apparatus you can use are made from these plastics. If your mould is a Plaster waste mould you will need Scopas Parting Agent. If your mould is made from anything else you will need two parting agents; a Wax Parting Agent and a water soluble plastic or PVA Parting Agent (Please note this is not the glue PVA!).

Casting and Mould Making

Resin really is a great medium as you can either make a mould from General Purpose Resin or from Fibreglass, depending on the nature of your design or sculpture. Again, as with the Laminating process, make sure you have the appropriate parting agent on your mould when casting into it. When making a structure to cast your Resin into, use plastic where possible as that will allow your mould to come off from the structure nicely. When Mould Making, make sure your model has the appropriate Parting Agent applied to it. You may be surprised to know that you can make a model from Clay and a mould from Resin. Use Filmo'Ront Acrylic Sealer to seal the Clay.

 

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