How do I make a Life cast?

We use 3 main materials for this process, although skin-safe silicones may also be used.

Alginate: This forms a gel-like skin over the  master or model.

Mod-roc: This is used mainly in making the support jackets that accompany a skin mould.

Plaster: Primarily used as a casting material; we use this to make our master copy of the live subject.

Life casting processes are regularly used to create prosthetics and special effects prop’s for movie’s.

Many life casting materials are single-use moulds of a body part (called, waste mould making). These materials are also very restrictive in terms of the materials we may use as casting agents.

Life casting’s will always need a little finishing when removed from the mould, fortunately plaster is ideal for sculpting and will also stick to itself. We can use this to our advantage when making full body casts, as ordinarily they are made up of several separate castings which are joined together later.

Using our knowledge of these materials we can bend the rules of traditional use. For example, we know that alginate shrinks as it dries. We can use this shrinking process to miniaturize many simple forms, like a face or head.

Using material properties to suite our needs help us to create many things that are not what they appear to be. For example we can use iron powder and the water content of Plaster simulate a rusted piece of metal.


  1. -Best for most life mould making and 

  casting applications

  1. -Sets quickly, minimizing stress on

  the model

  1. -Good for prosthetic work

  2. -Is a water-based gel, made primarily

  from seaweed

  1. -Ultimate texture capture, usable on

  almost any surface

- Good for shrinking objects


  1. -Good for most life mould making and 


  1. -Sets quickly, minimizing stress on

  the model

- Available in rolls, mod-roc is basically

  bandage impregnated with plaster

  1. -Good for making supporting jackets and

  multi-part moulds

  1. -Is a water-based material, making it  

  safe and easy to work with

  1. -Good form and surface capture


  1. -Good for almost all casting applications

  2. -Sets quickly

- Readily available and very low cost

  1. -Good for re-enforcing supporting

  jackets and multi-part moulds

  especially when used with plasters


  1. -Is a water-based material, making it  

  safe and easy to work with

  1. -Good for sculpting

  2. -Comes in a wide variety of types

  3. -Good for making dipped latex skin


Alginate, Mod-roc and Plaster

What is Life Casting?

Life casting is the process of using skin safe mould making materials to capture the human form. Some of the materials in this section are capable of replicating surface texture of skin including wrinkles, finger prints and skin pores!

Life casting is a very broad discipline that takes practice and patience. Sometimes many processes and materials may be required to produce a single piece. For example producing a brass cold-metal casting of a person’s face would involve:
1. Using alginate and mod-roc to create a 
   life-casting from a model
Using plaster to cast a master copy from the alginate/mod-roc mould
Use condensation silicone or latex to make a rubber skin
Use mod-roc or fibre-glass to make a supporting jacket
Only now can we remove the plaster master from  the rubber mould and begin our cold-metal casting


If you want to do a face cast using alginate, never try it for the first time without professional guidance.

There can be a real danger of inexperienced user’s accidentally blocking the model’s airways.


Life cast, aluminium cold metal casting taken from a silicone mould


Collection of plaster life casts taken from alginate and modroc moulds


Plaster casting of pregnant torso taken from an alginate and modroc mould


Flexible foam life cast, taken from a silicone skin mould


      Plaster and iron powder casting


A positive and a negative plaster cast, taken from  alginate  moulds


Full body cast, taken from several multi-part mod-roc moulds


Full plaster head cast
            Separate plaster life castings    
             embedded in a plaster tablet
 Life casting of a torso taken from an alginate and mod-roc mould, embedded in a sculpture
 Casting of a 3 year old’s feet, taken from an alginate and tin-tray mould
  Three family members hands on a         
             sculpted plaster base


Granite chips and resin casting taken from a silicone life cast torso

Note to users:

Life casting is a process which can be as versatile as the user. Once you understand the principles of the materials and how they work nothing is impossible.

As with many materials and process’s I have described throughout this resource, life casting is one of the easiest, yet involved skill to learn. Practise plays a huge role when attempting to master these techniques.

Alginate, mod-roc, and plaster are available from:

Alec Tiranti sculpting supplies

Prices vary:

£8.00 for 500g of alginate

£10.00 for 25kg and plaster

£2.00 per roll of mod-roc


Mould shrinking using alginate repeats