Sylmasta ClearCast CPU31 Urethane Casting Resin

£100.16 inc. VAT

Urethane casting resin which is non-yellowing and resistant to UV for making water clear casts and encapsulating objects

SKU: CPU31/1.835kg Category:


ClearCast CPU31 is an optically clear, low viscosity urethane casting resin used for making water-clear casts and the encapsulation of other objects.

Each 1.83kg ClearCast Kit contains 0.83kg of Part A and 1kg of Part B. The two parts are mixed together at a ratio of 100A:120B and then poured into a mould. The resin cures, forming a robust and accurate water-clear copy.

CPU31 ClearCast is non-yellowing and resistant to UV. Vibrant colours and colour effects can be achieved by adding pigment dispersions to the resin during mixing.

It is used by resin artists and jewellery makers to encapsulate existing items, creating unique and decorative pieces of art.

Sculptors create optically clear reproductions of their work using CPU31 and it is used within the movie, television and theatre industries for creating props and special effects.

It can also be used for making prototypes, lenses and by scale model makers who wish to make clear casts of existing models or modified kit parts.

Parts cast using CPU31 have negligible shrinkage. The low viscosity of CPU31 ensures easy mixing and pouring into the mould.

CPU31 has a pot life of 8 to 10 minutes a de-mould time of 24 hours at 25°C. The recommended casting thickness of CPU31 is 2mm to 10mm.

Please note that CPU31 ClearCast should only be used with moulding rubber suitable for casting with clear urethane resin. Other rubbers might affect curing.

For polyurethane casting resins which set to beige or grey, please see Polycast G26 Casting Resin.

Benefits of CPU31 ClearCast Urethane Casting Resin

  • Sets water-clear, is non-yellowing and resistant to UV
  • Can be mixed with pigment dispersion for vibrant colour effects
  • Low viscosity for good flow ability
  • Good adhesion to wooden materials


  • Casting multiple clear casts of master items and core models
  • Resin art and jewellery making projects requiring encapsulating objects in clear material
  • Making prototypes
  • Creating props and special effects


Can I add pigments to my ClearCast Resin?
Yes. Vibrant colours and colour effects can be achieved by adding pigment dispersions. We recommend that you mix a small amount of resin with your pigments first to test the compatibility.

Data Sheets

Safety Data Sheets are available on request. Please email

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