What can I make with Winterstone?

- Winterstone can be used for stand-alone sculptures, wall sculptures, architectural ornamentation, and the like.  

Why choose Winterstone?

- It is easy to use by either novice or professional sculptors;

- It does not require any sophisticated or expensive tools or equipment;

- It is light and easy to handle (relative to size) not only during the sculpting process but also in the final installation;

- It allows completion of the sculpture in its final finished form within a reasonable time and cost;

- It allows the sculptor total hands-on authorship of the sculpture, from initial concept, through build-up, to finishing and patination;

- It can be readily altered or repaired should the need arise;

- It can be used in reproduction of "thin shell" sculpture resulting in lightweight, strong casts.

How can Winterstone free my sculpting process?

- Winterstone allows complete freedom of artistic expression with regards to size, shape, colour and texture.

How can Winterstone be used?

- Winterstone can be directly modelled, carved and finished into a complete and final sculpture.

Are all Winterstone mixes the same?

- There are three different Winterstone mixes - each created to meet a specific need.  Sculpting Mix is used for direct modelling and hand lay-up casting, Casting Mix is used for slush cashing, Ultra Mix is extra fine with increased toughness and bonding properties which provides a highly polishable/burnishable surface to create specific metallic effects.

Does Winterstone need to be cast or fired?

- Winterstone does not need to be cast or fired - with Sculpting Mix you can model start to finish, but if you want to make a mold, go ahead - then copies can be made with Casting Mix.

Is Winterstone Toxic?

- Winterstone is safe and easy to use.

Do I need to wear any protective clothing while working with Winterstone?

- While mixing use of a dust mask is recommended.  If mixing by hand, use of latex gloves is recommended.

Casting Methods/FAQ

What is slush casting?

- Slush casting is when a liquid medium is poured into a mold and "slushed" around to provide a thin layer with complete coverage.  Slush casting usually involves multiple pours, leaving time between the pours to allow the medium to set.

What is lay-up casting?

- Lay-up casting is when a thicker medium is hand pressed into the mold to a desired thickness usually accomplished through two layers with a fiberglass mesh sandwiched between for reinforcement.

What is dry-pack casting?

- Dry-pack casting is when a crumbly medium is hand pressed into the mold and then appropriately reinforced with fiberglas smesh and another layer of Winterstone.  This process creates a cracked surface which can be left alone or filled after de-molding with another colour Winterstone.  The effects possible through this method include limestone, marble or ancient sculpture.

What is brush-on casting?

- Brush on casting is when a brush is used to apply the liquid medium to the face coat of the mold.  This is then backed up with additional layers either brushed on, slush cast or laid-up.

Which Winterstone mix should I use to cast my sculpture from a mold?

- Which method you choose will depend on the specific sculpture, its size, complexity, ultimate location placement (indoors vs outdoors).  Which method you use will determine which Winterstone mix you use.  Casting Mix and Ultra Mix are used for slush or brush on at least the face coat.  Sculpting Mix is used for lay-up.  

Technical Bulletins



 The addition of reinforcing such as metallic or fibreglass mesh into the outermost layering of WINTERSTONE sculpture or casting results in a "composite" material with substantially increased strength characteristics.   In essence, the reinforcing complements the inherent strength of the WINTERSTONE in withstanding the many and varied stresses to which the material may be subjected.  These may be intrinsic stresses such as drying shrinkage and thermal contraction or as may develop from externally applied loadings such as from shipping, handling, erection, heavy winds, abuse from the public, etc. -- most of which are common particularly to large pieces founded in an outdoor environment.  The thin shell "composite" working in conjunction with the basic armature of the sculpture/casting must be able to withstand these stresses.

The basic armature or "skeleton" (whether of steel wire or Styrofoam) onto which the WINTERSTONE shell is built-up will vary and will depend on the size and shape of the particular design.  The appropriate accompanying exterior "composite" shell will in most cases consist of:

1.    A minimum shell thickness of approximately 3/8 inch for small pieces, 1/2 or 3/4 inch for life size, and 3/4 to 1 inch for monumental pieces.

2.    A minimum of one layer and preferably two or three layers (depending on size and outdoor conditions) of closely spaced metallic or alkali-resistant fibreglass mesh should be embedded within the outermost shell thickness.  This should be complemented with integrally mixed fiberglass chopped strand for additional strength and resistance to shrinkage stresses.

Making the sculpture totally solid in casting or excessively thick in sculpting adds weight and not necessarily strength.  Particularly in sculpture exposed to severe daily temperature fluctuations the less mass there is the less thermal stresses and possible cracking occurs between a temperature-affected surface (e.g. from hot sun) and the relatively non-affected interior. Extra care and caution should be taken throughout the whole sculpturing process in producing sculpture for abnormal "abuse" or severe outdoor conditions.  The outer "composite" shell, critical in such situations should be built-up in accordance with the recommendations noted above and the procedures outlined in the respective Technical Bulletin.

If pieces of rod, wire, or mesh are used, they should overlap to maintain continuity of strength. In all cases, the reinforcing elements should be wholly encased to be completely effective.

The foregoing is also applicable to casting with WINTERSTONE, the only difference being in the particular mix used and in the application process itself.  In "slush-casting" the initial face thickness of say 1/16” to 1/8”, should be followed up with additional build-up on the inside with a WINTERSTONE mixture incorporating chopped fibre strand (e.g. 1 to 11/2% fibreglass) in situations where hand access is not possible.  Where hand access is possible then the "lay-up" process with the recommended mix and layering of mesh can be carried out similar but reverse to that of the sculpting process.  In either case a "composite" shell of the recommended thickness is required. 

In all cases where a finished piece, sculpted or cast, hollow or solid, is to be founded in an outdoor environment a wait of at least one month is recommended for further strength development.


Mix with the LEAST amount of water to achieve reasonable working consistency

Mix only sufficient quantity to use within noted times:   Sculpting 45 minutes;   Casting 5 minutes   Ultra 45 minutes

  • Maintain and/or regain desired consistency by re-mixing/remolding in mixing pot but avoid using additional water.
  • Spritz/sponge underling layer to “damp” with water before applying fresh mixture
  • Do not over-trowel fresh mixture during application to avoid bringing-up watery paste to surface — particularly important in final surface layer
  • Try to apply mixture in relatively uniform layers to prevent possible differential drying shrinkage
  • Incorporate the recommended reinforcing elements e.g. chopped Fiberglas strand/mesh or metallic wire/mesh —reinforcing elements must be totally encased with the WINTERSTONE mixture to be totally effective
  • Do not use Aluminum rods/wires as armature or reinforcing element
  • Serrate (roughen) each layer after application of fresh mix to provide “toothing” for follow-up layers and eliminate surface contour irregularities — easily done within initial ½ -1 hour
  • To prevent premature drying of freshly applied layer & hence possible “plastic” shrinkage cracks, spritz with water or cover with plastic sheathing/bag within 1-1 ½  hours after application [N.B. incorporating 1% chopped strand (by weight) in the mixture should eliminate this potential problem]
  • Always cover the piece with plastic sheathing/bag for the initial 24 hours after which should be allowed to air dry —particularly critical for final surface layering
  • Final surface refinement i.e. smoothing/sanding should not commence before the 3rd day.