Silastic High Grade Silicone - Buy Jesmonite
Silastic High Grade Silicone - Buy Jesmonite

Silastic High Grade Silicone

Sale price $65.00 Regular price $1,100.00


SILASTIC™ RTV-4250-S Kit Green is a high strength silicone for detailed reproduction of surfaces and objects for prototype design and production tooling, as well as artistic and renovation applications.

Two-component material consisting of a base and a curing agent, which when mixed, cure at room or elevated temperatures by an additional reaction.


  • Outstanding release properties
  • If required the product cure can be heat accelerated
  • Fast thick section cure at room temperature
  • Medium hardness
  • High inhibition resistance
  • High tear resistance
  • Very high elasticity, for easy removal of complex replica parts
  • Very low shrinkage and good dimensional stability
  • Can be used for high temperature casting applications
  • Can be made thixotropic (nonflowable) for vertical surface replication
  • Fast RTV cure, very fast cure with even, low heat
  • Very low viscosity for easy mixing and de-airing
  • Low durometer hardness

Artistic & Creative Uses:

  • Sculpture
  • Plastic Parts
  • Rapid Prototypes
  • Crafts
  • Casting

Data sheet and user guide

Q. Which material do I need?
  • AC100 is perfect for pouring into a mould and for internal use 
  • AC200 is softer and ideal for carving 
  • AC300 can be used the same as AC100 but has a lower polymer content for cost sensitive projects 
  • AC730 is primarily a laminating material to be applied in layers. Best when a stone effect is required, for internal or external use 

Q. What else do I need?
  • It is recommended when casting something long and flat, like a table top, to use our Quadaxial Matting 
  • If casting something more intricate with curves then our Chopped Strands are recommended 
  • We highly recommend using our High Shear Mixing Blade which has been specifically designed for Jesmonite to avoid bubbles in the mix 
  • If you're using a mould made of anything other than silicone, we advise you to use our Bonda Wax Release Agent 

Q. What is the natural colour of Jesmonite?
  • AC100, AC200 and AC300 cure with a colour of off white/cream. We have a range of pigments available. 

Q. Is Jesmonite GRC (Glassfibre Reinforced Concrete)?
  • Yes Jesmonite is classified as GRC (Glassfibre Reinforced Concrete). Due to its unique polymer content, versatility, being non-combustible and having much faster curing times than other GRC's, it is classed as a premium GRC product 

Q. Can I add other materials to the mix?
  • Yes you can. However we cannot guarantee the outcome 

Q. How much material do I need?
  • This all depends on dimensions, thickness, etc. As a guide for you to be able to calculate how much you need, at 10mm thick 18kg of material will make 1sqm 

Q. Can I become a reseller?
  • Jesmonite Australasia is a standalone/independent company that promotes/sells the Jesmonite® range of products to architects, designers, manufacturers and end users. Due to the terms of our Distribution/Supplier contract, we do not sell Jesmonite® via re-sellers 

Q. Do you also manufacture?
  • There are two parts to our company;
  1. Jesmonite Australasia which handles sales and distribution of Jesmonite products
  2. HGN Design which is an approved manufacturer of Jesmonite providing a full decorative architectural moulding and glass reinforced laminates manufacturing solution

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